Form 1 Agriculture Exams and Marking Schemes Free

NAME………………………………………………………………..ADM…………….

Class……………………………………………

JOINT EXAMINATION TERM THREE

AGRICULTURE FORM ONE

TIME: 2 HOURS

Instructions:

– This paper consists of 11 printed pages.

-This paper has three sections A,B and C.

– Answer ALL questions in sections A and B.

-Answer any TWO questions in section C.

For Examiners use:

SECTION A (ANSWER ALL THE QUESTIONS IN THIS SECTION)

1. Define the following terms. (2mks)
2. Arable farming

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1. Organic farming

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2. Name four branches of livestock farming. (2mks)

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3. State four characteristics of extensive farming system.             (2mks)

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4. List four aspects of rainfall that affect Agriculture.             (2mks)

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5. Give four constituents of soil.             (2mks)

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6. Name any four types of soil structures.             (2mks)

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7. State four ways of modifying soil P.H             (2mks)

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8. State the use of the following tools and equipments. (2mks)
9. Strip cup: ……………………………………………………………………………………….
10. Burdizzo: ………………………………………………………………………………………
11. Bolus gun: …………………………………………………………………………………….
12. Plumb bob: ……………………………………………………………………………………..
13. Give four ways of clearing land during preparations.             (2mks)

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10. Name two types of underground water sources.             (1mk)

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11. State two types of pipes used to convey water to the farm.             (1mk)

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12. List four types of irrigation systems.             (2mks)

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13. Give any four methods of drainage.             (2mks)

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14. Name any two types of organic manure.             (1mk)

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15. State four ways by which soil looses fertility.             (2mks)

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16. List four types of products a farmer can obtain from domesticated livestock. (2mks)

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17. Name two types of camel species reared in the farm.                                     (1mk)

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SECTION B (Answer ALL the questions in this section)

18. Study the diagram below and answer the questions that follow.

1. Identify the tool illustrated above.             (1mk)

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1. On the diagram label parts A,B and C.             (3mks)

A…………………………………………………………………………………………………….

B…………………………………………………………………………………………………….

C…………………………………………………………………………………………………

1. State two maintenance practices that can be done on the tool. (1mk)

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19. The diagram below illustrates a farming operation done during crop production
20. Identify the practice. (1mk)

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1. Describe how the above practice is done.             (2mks)

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1. State the importance of the practice.             (2mks)

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20. The diagram below illustrates a method of water harvesting

1. Identify the methodof water harvesting. (1mk)

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1. State factors that determine the amount of water harvested by the method above. (2mks)

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1. State the maintenance practices that should be done on part A. (2mks)

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1. State the aim of the experiment. (1mk)

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1. Identify soil types A,B,C. (3mks)

A………………………………………………………………………………………………………..

B………………………………………………………………………………………………………

C……………………………………………………………………………………………………..

1. Which of the above soil types is suitable for growing of paddy rice.             (1mk)

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SECTION C (Answer any TWO questions in this section)

22. (a) Discuss the process of water treatment. (12mks)

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(b) Describe various uses of water in the farm.                                                        (5mks)

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(c) State three reasons of treating water in the farm.                                                            (3mks)

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23. (a) Highlight five characteristics of fertile soils.             (5mks)

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(b) Describe various ways by which soil fertility can be maintained.                 (10mks)

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(c) List five factors that affect quality of farmyard manure.                                       (5mks)

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24. (a) State the importance of livestock in the farm. (5mks)

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(b) Describe the general characteristics of Dairy cattle breeds.                          (7mks)

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(c) Explain the uses of farm records.                                                                       (8mks)

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JOINT EXAMINATION

AGRICULTURE FORM ONE TERM THREE

MARKING SCHEME.

• a) Arable farming– this is the growing of crops on a cultivated land

1. b) Organic farming– this is the growing of crops and rearing of livestock without using agricultural chemicals.

• Pastoralism/mammalian livestock production

Fish farming/aquaculture

Bee keeping/apiculture

Poultry keeping

• Requires large tracts of land

Low capital investment

Low labour per unit area

Low yield per unit area

• Rainfall intensity

Rainfall amount

Rainfall distribution

Rainfall reliability

• Mineral matter

Organic matter

Soil air

Soil water

Soil living organisms.

• Single grained soil structure

Crumby Soil structure

Granular soil structure

Platy soil structure

Blocky soil structure

Prismatic soils structure

Columnar soil structure

• Lime application

Application of sulphur

Application of basic fertilizer

Application of acidic fertilizer

• Strip cup– used to check if a cow has mastitis

Burdizzo – used to castrate bulls, rams, buck or billy

Bolus guns – used to administer solid drugs through the mouth of an animal

Plumb bob – used to check if wall is vertically straight

• Slashing

Burning of vegetation cover

Tree felling

Use of herbicides

• springs

Wells

Boreholes

• Plastic pipes

Metal pipes (aluminium and galvanized iron pipes)

Hose pipes

• Surface irrigation ( flood, furrow,basin)

Overhead irrigation/ sprinkler

Sub-surface irrigation

Drip/trickle irrigation.

• Use of open ditches

Use of underground drain pipes

French drains

Cambered beds

Pumping

Planting trees e.g eucalyptus trees.

• Green manure

Compost manure

Farmyard manure

• Leaching

Soil erosion

Mono-cropping

Continuous cropping

Change in soil P.H.

Burning vegetation cover

Accumulation of salts

• Milk

Wool

Meat

Eggs

Honey

Blood.

• Dromedary

Bactrian

SECTION B

• hand saw.

1. A – toe

B – blade

C – Handle

1. Teeth setting should be done

Clean after use

Straighten blade when bent

Replace broken handle

Regular sharpening of teeth if blunt

Tighten loose nuts and screws

Oil the blade during long storage to reduce rusting

• Ridging

1. It is done by digging soil in a continuous lineand heaping it on one side to form a ridge and furrow.

1. Promotes easy harvesting of tubers

Promotes expansion of root tubers

Furrows help to conserve water

Ridges promote anchorage

Promotes production of seeds in ground nuts

• Roof water harvesting/ roof catchment.

1. Surface area of the roof

Amount of rainfall/ Intensity

1. Clean to remove dirt

Repair broken or leaking points

Place it on a strong base to resist water pressure

Paint iron sheet tanks to avoid rusting.

• To compare capillarity action in different soils

1. A- sand soil

B- Loam soil

C – Clay soil

1. soil type C

SECTION C

• Filtration at water intake – it is done by series of sieves to remove large particles

Softening of water – in the softening chamber, soda ash is added to soften water and alum (aluminium sulphate) to coagulate solid particles

Coagulation and sedimentation – the tank is open to allow aeration which removes bad smell, water stays for 36 hours to kill bilharzia worms.

Filtration – done using different sizes of gravel and a layer of sand to remove small solids

Chlorination – chlorine is added using a doser to kill micro organisms

Storage – water is stored awaiting distribution

1. Domestic use e.g cooking

Washing animal structures

Construction

Diluting chemicals

Watering plants

Watering animals

Promotes aquaculture

Washingfarm equipments

Cooling machines

Processing of farm produce.

1. To remove chemical impurities

To remove bad smell and taste

To kill disease causing micro organisms

To remove sediments of solid particles

• Good depth

Proper drainage

Good water holding capacity

Correct P.H

Adequate nutrient supply.

Free from excessive infestation of soil borne pests and diseases.

1. Control soil erosion

Crop rotation

Weed control

Minimum tillage

Inter cropping

Proper drainage

Control of soil P.H

Use of organic manure

Use of inorganic fertilizer

Avoid practise that reduce soil nutrients e.g burning of vegetation cover

1. Type of animal used

Type of food eaten

Typeof litter / bedding used

Method of storage

Age of farm yard manure

• Source of food

Source of income when sold

Provide animal power

Source of raw materials

Cultural uses e.g status symbol, medium of exchange, social ceremonies and recreational purposes.

1. Their bodies are wedge/ triangular shaped

They have a straight topline.

They have prominent milk veins

They are docile with mild temperament

They have visible pin-bone

They have well set apart hind quarters to give room for big udder

They have large stomach capacity therefore eat more and hence high milk production

They have large and well developed udder.

1. It shows the history of the farm

It helps to detect losses or thefts in a farm

Shows whether the farm is making profit or losses

Facilitates easy planning and budgeting

Makes it easy to share profit and losses during partnership

Helps to compare performance of different enterprises within a farm

Helps to settle disputes among heirs to the estate if farmer dies without leaving a will

Helps in assessment of income tax therefore reduced taxation

Helps to determine worth or value of the farm by comparing assets and liabilities

Supportsinsurance incase of death, theft or fire

Provides labour information e.g NSSF dues

Alupe University Course List, Fees, Requirements, How to Apply

SULPHUR AND ITS COMPOUNDS

 Objectives

By the end of the Chapter, the learner should be able to:

(a)  Name the sources of sulphur.

(b)  Describe the extraction of sulphur.

(c)  Describe the preparation of the allotropes of sulphur.

(d)  State the properties and uses of sulphur.

(e)  Name and describe the preparation of the oxides of sulphur.

(f)  State the properties and uses of the oxides of sulphur.

(g)  Describe the contact process for the manufacture of sulphuric acid.

(h)  Describe the properties and state the uses of sulphuric acid.

(i)   Describe the preparation and state the properties of hydrogen sulphide.

(j)  Explain pollution effects of sulphur containing compounds.

SULPHUR AND ITS COMPOUNDS

Sulphur is the second member of group VI elements. It is placed just below oxygen in the periodic table. It has an atomic number 16 hence its electron arrangement is 2.8.6.

Sulphur occurs naturally as an element in deposits in places such as Texas and Louisiana in U.S.A, Sicily in Italy, and various places in Japan.

Sulphur also occurs in combination with other elements as sulphides and sulphates. The sulphide ores include copper pyrites (CuFeS₂) and iron pyrites (FeS₂).

The sulphate ores include gypsum (CaSO₄.2H₂O)and anhydrite (CaSO₄). Petroleum gas and coal mines contain sulphur in the form of hydrogen sulphide gas.

Sulphur and its allotropes

Extraction OfSulphur: The Frasch process

The Frasch process is  employed in the extraction of Sulphur. The process is based on the low melting point of sulphur which ranges between 113 °C and 119°C. In the Frasch process, three concentric pipes of different diameters 2 cm, 8 cm, and 15 cm are sunk into the sulphur deposits underground.

Water is heated to about 170°C under pressure of about 10 atmospheres and is forced down the outermost pipe. The pressure ensures that the water remains in liquid state at such high temperature.

Hot air at a pressure of 15 atmospheres is forced down the innermost pipe. This produces a light froth consisting of a mixture of molten sulphur and water. The high pressure forces the mixture up the middle pipe.

The mixture is run into large tanks on the surface where the sulphur solidifies at 115°C, Separates from the water and is stored. Sulphur obtained this way in usually over 99% pure.

Allotropes of Sulphur

Sulphur exhibits allotropy. The main allotropes are rhombic and monoclinic sulphur

Rhombic Sulphur

Rhombic sulphur is also referred to as octahedral or α-sulphur. It is a bright yellow crystalline

solid with an octahedral shape.

(a) A crystal of rhombic sulphur.                 (b) Packing of rhombic sulphur molecules in a crystal

How to prepare Rhombic sulphur:

Place two spatulafuls of powdered sulphur in a boiling tube containing 10 cm³ of carbon(IV) sulphide. Stir and filter the contents of the tube into a dry beaker using a dry filter paper. Allow the filtrate to evaporate slowly. Use a hand lens to examine the crystals formed.

Rhombic sulphur melts at 113°C and has a density of 2.06 g/cm³. It is the stable allotrope below 96°C. Above this temperature, it slowly changes into monoclinic sulphur.

Monoclinic Sulphur

Monoclinic sulphur is also referred to as prismatic or ß – sulphur. It is a pale yellow crystalline solid. The crystals appear needle-like when observed using a hand lens. The actual shape of the crystal is a hexagonal prism.

• A crystal of monoclinic Sulphur. (b) Packing of monoclinic Sulphur molecules in a crystal

How to prepare monoclinic sulphur

Place some powdered sulphur in an evaporating dish and heat gently until the sulphur melts. Using a glass rod, stir and add more sulphur a little at a time until the dish is almost full of molten sulphur.

Remove the source of heat and allow the sulphur to cool and form a crust on the surface. Using a thin glass rod, carefully pierce two holes on widely separated points

in the crust as shown below .

Immediately pour out the molten sulphur. Remove the crust by cutting round the edge of the dish with a knife. Use a hand lens to observe the crystals that have formed on the underside of the crust.

Monoclinic sulphur has a melting point of 119°C and a density of 1.98 g/cm³. Below 96°C monoclinic sulphur gradually changes to rhombic sulphur. This temperature of 96°C is the transition temperature for rhombic and monoclinic sulphur.

The temperature at which one allotrope of an element changes to another is called the transition temperature.

Non-crystalline – (amorphous) forms of Sulphur

Include plastic, colloidal, and powdery sulphur.

Plastic sulphur is prepared by heating powdered sulphur until it boils. The boiling sulphur is then poured in a thin continuous stream into a beaker containing cold water. Long elastic yellow threads of plastic sulphur are formed.

This form of sulphur is insoluble in carbon(IV) sulphide. It turns into hard rhombic sulphur if left for a few days.

When dilute hydrochloric acid is added to a test-tube containing a dilute solution of sodium thiosulphate, Na₂S₂O₃, a yellow precipitate of colloidal sulphur is deposited.

N₂S₂O₃,(aq) + 2HCl(aq)  2NaCl(aq) + H₂O(l) + SO₂(g) + S(s)

Powdery sulphur may be prepared by saturating distilled water with hydrogen sulphide. The solution is then exposed to air. A white powder is deposited.

H₂S(g) + Water  H₂S(aq)

2H₂S(aq) + O₂(g)  2H₂O(l) + 2S(s)

Physical Properties of Sulphur

Sulphur is a yellow non-metallic element. A molecule of sulphur consists of a puckered ring of eight atoms of sulphur joined together by strong covalent bonds as shown below. .

Sulphur is soluble in organic solvents such as benzene, methyl benzene, and carbon(IV) sulphide. It does not dissolve in water.

Effect of heat on sulphur.

When the yellow powder is gently heated, it melts at 113°C to a clear amber liquid. At this temperature molten sulphur has a low viscosity, and flows easily. This liquid is made up of rings of sulphur molecules consisting of eight atoms of sulphur, S₈.

On further heating the liquid gradually darkens. At 160°C, it becomes reddish-brown, and very viscous such that the test-tube may be inverted without the liquid sulphur pouring out. These changes are due to the breaking of the S₈ rings which join to form long chains with over 100,000 atoms of sulphur. As the chains entangle with one another, the viscosity of

the liquid increases.

Long chains of sulphur atoms.                                                                     Shorter chains of sulphur atoms

Above 160°C, the liquid darkens further and becomes almost black. Near the boiling point the liquid becomes more mobile. This is due to the breaking of the long chains to shorter chains.

The liquid boils at 444°C and forms a reddish-brown vapour consisting of S₈, S₆ and S₂ molecules which cools to form a yellow sublimate. This sublimate is known as “flowers of sulphur” and consists mainly of S₈ rings.

Chemical Properties of Sulphur

Reaction of sulphur with oxygen, iron powder and  copper

Sulphur burns in oxygen with a bright blue flame forming misty fumes with a choking smell.

The gas is mainly sulphur(VI) oxide (sulphur dioxide) SO₂, with traces of sulphur(IV) oxide (sulphur trioxide, SO₃).

S(s) + O₂(g)  SO₂(g)

2S(s) + 3O₂(g)  2SO₃(g)

The moist blue litmus paper turns red indicating that the oxides produced when sulphur burns are acidic.

Sulphur combines directly with some elements to form sulphides.

• When a mixture of sulphur, and iron powder is heated, a highly exothermic reaction occurs. Once the reaction has started at one point, the glow spreads through the mixture without further heating, forming iron(II) sulphide. This is because the heat produced during the reaction is high enough to sustain the reaction.
• Hot powdered copper similarly combines with heated sulphur forming copper(I) sulphide.
• Sulphur also combines with some non-metals such as carbon and hydrogen forming non-metallic sulphides.

Carbon combines with sulphur at high temperatures to form carbon(IV) sulphide. Hydrogen combines with sulphur to form hydrogen sulphide.

Reaction of sulphur with concentrated acids

Sulphur is easily oxidised by both concentrated nitric(V) and sulphuric(VI) acids.

• When warmed with concentrated nitric(V) acid, sulphur is oxidised to sulphuric(VI) acid. The sulphate () ion in the acid forms a white precipitate with barium ions in the solution. The nitric(V) acid itself is reduced to red brown nitrogen(IV) oxide and water.

S(s) + 6HNO₃(aq)  H₂SO₄(aq) + 6NO₂(g) + 2H₂O(l)

• Concentrated sulphuric(VI) acid oxidises sulphur to sulphur(IV) oxide while the acid is reduced to sulphur(IV) oxide, and water.

S(s) + 2H₂SO,(l)  3SO₂(g) + 2H₂O(l)

Concentrated hydrochloric acid does not react with sulphur because it is not an oxidising agent.

Uses of Sulphur

• Manufacture of sulphuric(VI) acid.
• As a fungicide.
• In the manufacture of bleaching agent used to bleach wood pulp in the paper industry.
• Vulcanisation (hardening) of rubber.
• Used in smaller quantities in the manufacture of dyes, and fireworks..

The Compounds of Sulphur

Sulphur forms several compounds. The common compounds include the oxides, sulphuric acid and hydrogen sulphide

Oxides of Sulphur

Sulphur forms two oxides namely sulphur(IV) oxide, SO₂, and sulphur(VI) oxide SO₃.

Sulphur(IV) Oxide, SO₂

Laboratory preparation of sulphur (IV) oxide.

Sulphur(IV) oxide is prepared in the laboratory by the action of dilute hydrochloric acid on a suitable sulphite such as sodium sulphite.

Na₂SO₃(s) + 2HCl(aq)  SO₂(g) + 2NaCl(aq) + H₂O(l)

The gas may also be prepared by the action of concentrated sulphuric(VI) acid on copper turnings. The reaction should be carried out in a fume cupboard.

Cu(s) + 2H₂SO₄(aq)  SO₂(g) + 2H₂O(l) + CuSO₄(aq)

Sulphur(IV) oxide is dried by passing it through concentrated sulphuric(IV) acid and collected by downward delivery. The gas jar is confirmed to be full of the gas when the paper soaked in orange potassium chromate(VI) turns green.

Physical Properties of Sulphur(IV) Oxide

Sulphur(IV) oxide is a colourless poisonous gas with a characteristic irritating, and choking smell.

It has a boiling point of –10°C and is readily liquefied under pressure.

Discussion Questions

1. Give a reason why sulphur(IV) oxide is collected by downward delivery.

It is denser than air, hence can be collected by downward delivery.

2. Explain the observation made when a test-tube full of sulphur(IV) oxide is inverted in a trough of water.

When a test-tube full of the gas is inverted in a trough of water, the water level rises rapidly inside the test-tube. This shows that the gas is soluble in water.

3. Explain the observation made when:

(a)  A damp litmus paper was dropped into a test-tube containing sulphur(IV) oxide gas.

When a moist blue litmus paper is dropped into a test-tube containing sulphur(IV) oxide, it turns red showing that the gas is acidic. The gas has no effect on dry litmus. The solution of the gas in water is sulphuric(IV) acid. This is a weak dibasic acid.

SO₂(g) + H₂O(l)  H₂SO₃(aq)

The acid is responsible for the change in colour of the moist litmus.

• Sodium hydroxide solution is added to sulphur(IV) oxide.

When sodium hydroxide solution is added to sulphur(IV) oxide gas, neutralisation occurs. The sulphuric(IV) acid formed reacts with sodium hydroxide forming a salt and water. During the reaction between the acid and sodium hydroxide, two types of salts are formed, a normal and an acid salt.

Chemical Properties of Sulphur (IV) Oxide

Bleaching Action of Sulphur(IV) Oxide

Sulphur(IV) Oxide is a bleaching agent. It bleaches by reduction. This property is applied in paper industries to bleach paper.

Discussion Questions

1. State and explain what is observed when coloured flowers are dropped in a gas jar containing Sulphur (IV) oxide.

When coloured flowers are dropped into a gas jar containing sulphur(VI) oxide, the flowers are bleached. Sulphur(IV) oxide combines first with the moisture, forming sulphuric(IV) acid. The sulphuric(IV) acid then combines with oxygen from the dye to form sulphuric(VI) acid. When the dye loses oxygen it becomes colourless. In this reaction, the dye undergoes reduction while the sulphuric(IV) acid is oxidised.

SO₂(g) + H₂O(l)  H₂SO₃(aq)

H₂SO₃(aq) + Dye  H₂SO₄(aq) + Colourless material.

2. Give a reason why newsprint paper turns brown after some time.

During the manufacture of paper, reducing agents such as sulphuric(IV) acid are used to bleach the materials. When such paper is exposed to the atmosphere in the presence of sunlight, the oxygen removed during bleaching is restored. This explains why newsprint paper turns brown after sometime.

Reducing Action of Sulphur(IV) Oxide

Sulphur(IV) oxide is a strong reducing agent. The reducing property is only displayed when the gas is in aqueous state.

Discussion Questions

1. Explain the observations made when sulphur(IV) oxide gas is reacted with:

(i)  Acidified potassium chromate(VI) solution.

Acidified potassium dichromate(VI) turns from orange to green when reacted with sulphur(IV) oxide. The chromium(VI) ion in the dichromate () is reduced to chromium(III) ion.

This is a test for Sulphur (IV) Oxide

(ii)  Acidified potassium manganate(VII) solution

The colour of acidified potassium manganate(VII) turns from purple to colourless when reacted with sulphur(IV) oxide. This is because the manganese(VII) ion in the manganate ion () is reduced to manganese(II) ion.

(iii) Acidified bromine water followed by a few drops of barium chloride solution.

Red brown acidified bromine water is decolourised when reacted with sulphur(IV) oxide. The bromine water is reduced to hydrobromic acid as the sulphur(IV) oxide is oxidised to sulphate.

2. Explain the observations made when:

(i)   Concentrated nitric(V) acid is added to a test-tube full of sulphur(IV) oxide, followed by barium chloride solution.

When concentrated nitric(V) acid is added to a test-tube containing sulphur(IV) oxide gas brown fumes of nitrogen(IV) oxide are given off.

The nitric(V) acid is reduced to nitrogen(IV) oxide while the sulphuric(IV) acid is oxidised to sulphuric(VI) acid. When a solution of barium chloride is added to the mixture, a white precipitate of barium sulphate is formed indicating the presence of sulphate,  ions.

(ii)  Sulphur(IV) oxide is reacted with a hot solution of iron(II) chloride.

When warm iron(III) chloride solution is added to sulphur(IV) oxide the yellow colour changes to green. Sulphur(IV) oxide reduces yellow iron(III) ions, Fe³⁺(aq) to pale green iron(II), Fe²⁺(aq) ions.

(iii) Sulphur (IV) Oxide is reacted with hydrogen peroxide

Similarly, hydrogen peroxide is reduced to water.

(Iv) A burning splint is lowered into a gas jar containing Sulphur (IV) oxide.

When a burning splint is lowered into a test-tube containing sulphur(IV) oxide, it is put off showing that the gas does not support combustion or burn. However, in the presence of a catalyst, the gas is oxidised to sulphur(VI) oxide.

Oxidising Action of Sulphur(IV) Oxide

Sulphur (IV) Oxide also acts as an Oxidising agent. It oxidises burning magnesium to magnesium oxide and hydrogen sulphide to Sulphur.

Discussion Questions

Explain the observations made when burning magnesium is lowered into a gas jar of sulphur(IV) oxide.

When burning magnesium is lowered into a gas jar of sulphur(IV) oxide, it continues to burn for some time. White fumes of magnesium oxide, and yellow specks of sulphur are formed.

Burning magnesium continues to burn in sulphur(IV) oxide because the heat produced by the burning magnesium decomposes the sulphur(IV) oxide to sulphur and oxygen. The magnesium combines with the oxygen to form magnesium oxide.

In this reaction, sulphur(IV) oxide is an oxidising agent, supplying oxygen to magnesium.

Explain the observations made when a gas jar of dry hydrogen sulphide gas is inverted over a test-tube containing Sulphur(IV) Oxide and a few drops of water added.

When a gas jar of dry hydrogen sulphide gas is inverted over a test-tube containing dry sulphur(IV) oxide, there is no observable change. When a few drops of water are added into each gas jar and the mixture is shaken, a yellow deposit of sulphur is produced.

2H₂S(g) + SO₂(g)  3S(s) + 2H₂O(l)

The reaction only takes place when the gases are moist. Sulphur(IV) oxide acts as an oxidising agent.

Sulphur (VI) Oxide, SO₃

Preparation of Sulphur (VI) Oxide (SO₃)

In the laboratory, sulphur(VI) oxide is prepared by reacting sulphur(IV) oxide with oxygen in the presence of a platinum catalyst..

Lab Preparation of Sulphur Trioxide, SO₃

Equation for the reaction taking place,

2SO₂(g)+ O₂(g)  2SO₃(s)

Other Methods

Decomposing of sodium hydrogen sulphate.

Discussion Questions

1. State the purpose of the following in the set up.

(a)  Concentrated sulphuric(VI) acid.

Sulphur(IV) oxide and oxygen gases are dried by passing them through concentrated sulphuric(VI) acid

(b)  Freezing salt ice mixture.

The sulphur(VI) oxide is cooled by the freezing salt-ice mixture and it solidifies.

(c)  Anhydrous calcium chloride.

Since sulphur(VI) oxide is deliquescent, calcium chloride is used to keep it free from moisture

1. Write an equation for the reaction that takes place in the combustion tube.

2SO₂(g)+ O₂(g)  2SO₃(s)

1. Comment on the method of collection of sulphur(VI) oxide.

The sulphur(VI) oxide is cooled by the freezing salt-ice mixture and it solidifes. This allows it to be collected as illustrated.

Test for Sulphate and Sulphite ions.

The addition of bariumchloride on sodium sulphate and sodium sulphite is used to test for sulphate and sulphite ions.

Test

To 2 cm³ of sodium sulphate in a test-tube:

(i)  Add 2 cm³ of barium chloride(or nitrate) solution.

(ii)  To the mixture in(i) above add 2 cm³ of dilute hydrochloric acid (or dilute nitric(V) acid).

Repeat procedure (i) and (ii) using 2 cm³ solution of sodium sulphite.

Discussion Questions

1. State the observations made when barium chloride solution is added to:

(a)  Sodium sulphate solution and barium sulphite solutions.

When barium chloride solution is added to sodium sulphate and sodium sulphite solutions, a white precipitate is formed in each case. The white precipitates are barium sulphate and barium sulphite respectively.

2. Why is the acid added to the mixture?

The acid is  added to distinguish between the sulphate and sulphite ions.

When dilute hydrochloric acid is added to the mixture containing barium sulphate precipitate, the precipitate does not dissolve.

However, when dilute hydrochloric acid is added to the mixture containing barium sulphite precipitate, the precipitate dissolves. This is the test for sulphite ions.

BaSO₃(s) + 2HCl(aq)  BaCl₂(aq) + SO₂(g) + H₂O(l)

BaSO₃(s) + 2H⁺(aq)  Ba²⁺(aq) + SO₂(g) + H₂O(l)

Uses of Sulphur(VI) Oxide

Sulphur(VI) oxide is used:

• As a major raw material in the large scale manufacture of sulphuric(VI) acid.
• To make calcium hydrogen sulphite, Ca(HSO₃)_2, used to bleach wood pulp in the manufacture of paper.
• As a fumigant.
• As a preservative in jam and fruit juices.

Sulphuric (VI) acid

Large Scale Manufacture of Sulphuric(VI) Acid

Sulphuric(IV) acid is manufactured by the contact process shown below.

The raw materials for its manufacture are sulphur(IV) oxide and air.

Sulphides or sulphur are burnt in air to produce sulphur(IV) oxide.

• Burning of sulphur is the most convenient method of producing sulphur(IV) oxide.

S(s) + O₂(g)  SO₂(g)

The sulphur(IV) oxide contains dust particles as impurities.

• The impurities reduce the surface area of the catalyst, thus impairing its efficiency. These impurities are said to poison the catalyst.
• The dust impurities are removed by electrostatic precipitation.

The mixture of gases is passed through concentrated sulphuric(VI) acid in order to dry it.

After purification, the gaseous mixture is pre-heated in the heat exchanger to attain suitable reaction temperature before being passed into the catalytic chamber.

In the catalytic chamber, sulphur(IV) oxide and oxygen react to form sulphur(VI) oxide.

Either platinum or vanadium(V) oxide may be used as catalyst.

• However, the vanadium(V) oxide(V₂O₅) is preferred because it is cheaper and less easilypoisoned.

For maximum yield of sulphur(VI) oxide in the contact process, low temperature and high pressure are necessary.

• However, at low temperature the reaction is slow while high pressure is expensive tomaintain. A temperature of 450°C and pressure of 2 to 3 atmospheres are used and are referred to as optimum conditions.

The sulphur(VI) oxide is not dissolved directly in water because the excessive heat generated could boil the acid to produce a mist of fine droplets of sulphuric(VI) acid in air. Hence, the gas is dissolved in concentrated sulphuric(VI) acid to form oleum (H₂S₂O₇).

• Sulphuric(VI) acid is obtained by diluting oleum with water.

H₂S₂O₇(1) + H₂O(l)  2H₂SO₄(l)

During the contact process, not all the sulphur(IV) oxide is converted into sulphur (VI) oxide: only 98% conversion of sulphur(IV) oxide to sulphur(VI) oxide occurs.

• Sulphur(IV) oxide is a pollutant, passing the exhaust gases through chimneys lined with calcium hydroxide reduces the amount of sulphur(IV) oxide released to the atmosphere. This is referred to as scrubbing the gas.

Ca(OH)₂(aq) + SO₂(g)  CaSO₃(s) + H₂O(l)

• In some industries, filters fitted with strong alkalis are installed to remove any traces of acid or mist from exhaust gases.

Properties of Sulphuric(VI) acid

Concentrated sulphuric(VI) acid is a colourless oily liquid.

It has a density of 1.84 g/cm³ and boils at 338°C.

It is very soluble in water. It dissolves with evolution of heat (exothermic reaction)

Concentrated sulphuric(VI) acid is hygroscopic. This property makes the acid a suitable drying agent for gases which do not react with it. The acid readily removes water from hydrated salts.

Concentrated sulphuric(VI) acid is a strong dehydrating agent.

A dehydrating agentis a substance which is capable of removing chemically combined water or the elements of water from a compound.

The process of removing water or its elements from a compound is called dehydration.

The acid dehydrates alcohols to to alkenes, methanoic acid to carbon(II) oxide and sugar to carbon. The sugar crystals are charred to a black mass when concentrated sulphuric (VI) acid is added to it.

Hot concentrated sulphuric(VI) acid is a strong oxidising agent.It oxidises metals such as copper and non metals such as carbon and sulphur.

It is also a less volatile acid and displaces more volatile acids from their salts.

Discussion Questions

1. Explain why the acid should be added to water and not water to acid.

If water is added to the acid, fumes are produced since the reaction is quite exothermic. For this reason, dilution of the concentrated acid should always be carried out by adding small portions of the acid slowly to a large volume of water with constant stirring.

2. Explain the observation made when concentrated sulphuric(VI) acid was added to:

(a)  Copper(II) sulphate crystals.

When the acid is added to blue crystals of copper(II) sulphate pentahydrate, CuSO₄.5H₂O, a white powder of the anhydrous salt is formed.

• Sugar crystals.

When concentrated sulphuric(VI) acid is added to sugar crystals, the crystals are charred to a black mass.

(c) Methanoic acid and ethanol

Methanoic acid is dehydrated to form carbon(II) oxide.

The acid also dehydrates alcohols to alkenes.

3. Explain the observations made when concentrated sulphuric(IV) acid was reacted with:

(a)  Copper and zinc metals

When copper or zinc metal is added to concentrated sulphuric(IV) acid, a gas is produced which turns acidified potassium chromate(VI) solution from orange to green and decolourises acidified potassium manganate(VII) solution.

Cu(s) + 2H₂SO₄(l)  CuSO₄(aq) + SO₂(g) + 2H₂O(l)

Zn(s) + 2H₂SO₄(l)  ZnSO₄(aq) + SO₂(g) + 2H₂O(l)

(b)  Carbon and Sulphur powder.

Hot concentrated sulphuric(VI) acid  oxidises non-metals such as sulphur and carbon.

S(s) + 2H₄SO₄(l)  3SO₂(g) + 2H₂O(l)

C(s) + 2H₂SO₄(l)  2SO₂(g) + CO₂ (g) + 2H₂O(l)

4. Explain the observation made when concentrated sulphuric(VI) acid was added toPotassium nitrate crystals and Sodium chloride.

Concentrated sulphuric(IV) acid is a less volatile acid. It displaces more volatile acids from their salts.

KNO₃(s) + H₂SO₄(l)  HNO₃(g) + KHSO₄(s)

NaCl(s) + H₂SO₄(l)  HCl(s) + NaHSO₄(s)

Reactions of Dilute Sulphuric(VI) Acid

Reactions with metals

When dilute sulphuric(VI) acid is added to magnesium or zinc, an effervescence occurs as a colourless gas which produces a ‘pop’ sound when a burning splint is applied is produced. The reaction between magnesium and dilute sulphuric acid is more vigorous than that of zinc and dilute sulphuric(VI) acid.

Mg(s) + H₂SO₄ (aq)  MgSO₄(aq) + H₂(g)

Zn(s) + H₂SO₄(aq)  ZnSO₄(aq) + H₂(g)

Copper is below hydrogen in the reactivity series of the metals. It does not therefore displace hydrogen from dilute sulphuric(VI) acid.

The reactions between metals high in the reactivity series such as potassium and sodium with dilute acids are very violent and should never be attempted. The vigour of the reaction decreases as you go down the reactivity series.

Reactions with carbonates.

Effervescence occurs when dilute sulphuric(VI) acid is added to the carbonates of zinc, sodium and copper. The colourless gas produced forms a white precipitate with lime water showing that it is carbon(IV) oxide.

ZnCO₃(s) + H₂SO₄(aq)  ZnSO₄(aq) + H₂O(l) + CO₂(g)

Na₂CO₃(s) + H₂SO₄(aq)  Na₂SO₄(aq) + H₂O(l) + CO₂(g)

CuCO₃(s) + H₂SO₄(aq)  CuSO₄(aq) + H₂O(l) + CO₂(s)

The reaction between calcium carbonate and dilute sulphuric (VI) acid stops soon after it starts. This is because the calcium sulphate produced during the reaction is insoluble.

CaCO₃(s) + H₂SO₄(aq)  CaSO₄(s) + H₂O(l) + CO₂(g)

The insoluble calcium sulphate forms a coating on the sulphate calcium preventing further contact with the acid. As a result the reaction stops. Lead(II) carbonate behaves in a similar manner.

Reaction with metal oxides and hydroxides

When dilute sulphuric(VI) acid reacts with a metal oxide or hydroxide, a salt and water are formed. However, those metal oxides whose sulphates are insoluble react only for a short while.

Thus, the reaction between dilute sulphuric(VI) acid, and lead(II) oxide stops almost immediately. This is due to the formation of an insoluble layer of lead(II) sulphate which effectively prevents further contact between the acid and the oxide.

2NaOH(aq) + H₂SO₄(aq)  Na₂SO₄(aq) + 2H₂O(l)

Uses of Sulphuric(VI) acid

1. Manufacture of fertilisers.
2. Processing of metal ores.
3. Manufacture of detergents.
4. Manufacture of plastics.
5. Manufacture of dyes and paints.
6. Used in lead acid accumulators

Hydrogen Sulphide (H₂S)

Hydrogen sulphide is a gaseous compound of sulphur which is very poisonous. It occurs naturally in some deposits mixed with natural gas.

Preparation and properties of hydrogen sulphide

The set-up below can be used to prepare hydrogen sulphide.

.

Hydrogen sulphide is formed when dilute hydrochloric acid is added to iron(II) sulphide.

FeS(s) + 2HCl(aq)  FeCl₂(aq) + H₂S(g)

However, any metal sulphide, and dilute acid can be used to prepare hydrogen sulphide gas.

The gas is collected over warm water since it dissolves in cold water.

The gas can be dried by passing it through a U-tube packed withanyhydrous calcium chloride.

The gas cannot be dried using concentrated sulphuric(VI) acid because it would be oxidised to sulphur.

3H₂S(g) + H₂SO₄(l)  4S(s) + 4H₂O(l)

Physical properties of hydrogen sulphide

Hydrogen sulphide is a colourless gas with a characteristic smell of rotten eggs. It is very poisonous. It is slightly soluble in cold water. It is denser than air.

Chemical properties of hydrogen sulphide

(a) Reaction with water

Hydrogen sulphide dissolves in water to form a weak acidic solution of H₂S(aq).

Aqueous hydrogen sulphide is a weak dibasic acid. It forms two types of salts, the hydrogen sulphides, and the sulphides, e.g., sodium hydrogen sulphide (NaHS) and sodium sulphide (Na₂S).

(b) Reaction with Oxygen

Hydrogen sulphide burns in air with a pale blue flame. In a limited supply of air, sulphur and water are formed.

2H₂S(g) + O₂(g)  2S(s) + 2H₂O(g)

In excess air, sulphur(IV) oxide and water are formed.

2H₂S(g) + 3O₂(g)  2SO₂(g) + 2H₂O(g)

(c) Reactions of hydrogen sulphide as a reducing agent

Hydrogen sulphide is a strong reducing agent and is readily oxidised to sulphur, which is precipitated as a yellow solid. Red-brown bromine water is reduced by hydrogen sulphide forming colourless hydrogen bromide solution and a yellow precipitate of sulphur.

Br₂(aq) + H₂S(g)  2HBr(aq) + S(s)

Yellow iron(III) chloride in solution is reduced to green iron(II) chloride.

H₂S(g) + 2FeCl₃(aq)  2FeCl₂(aq) + S(s) + 2HCl(aq)

Acidified purple potassium manganate(VII) solution is reduced to a colourless manganese(II) solution.

Similarly, acidified orange chromate(VI) is reduced to green chromium(III) ions solution.

A solution of hydrogen peroxide is reduced to water, and a yellow precipitate of sulphur is formed.

H₂O₂(aq) + H₂S(g)  2H₂O(l) + S(s)

Brown fumes of nitrogen(IV) oxide are produced and pale yellow sulphur is deposited when hydrogen sulphide is bubbled into dilute nitric(V) acid.

2HNO₃(aq) + H₂S(g)  2NO₂(g) + 2H₂O(l) + S(s)

Dilute sulpharic(VI) acid is reduced to sulphur by hydrogen sulphide.

H₂SO₄(aq) + 3H₂S(g)  4S(s) + 4H₂O(T)

(d) Reaction with aqueous metallic ious

Hydrogen sulphide reacts with some metal ions in solution to form precipitates of metal sulphides. When bubbled through aqueous copper(II) sulphate, a black precipitate of copper(II) sulphide is formed.

Cu²⁺(aq) + S^2-(aq) CuS(s)

Other metal sulphides are precipitated as shown by the following ionic equations.

Zn²⁺(aq) + S^2-(aq)  ZnS(s)

Pb²⁺(aq) + S^2-(aq) PbS(s)

Fe²⁺(aq) + S^2-(aq) FeS(s)

Most sulphides are insoluble in water except those of sodium, potassium and ammonium. When equal volumes of equimolar hydrogen sulphide and sodium hydroxide solutions are reacted, sodium hydrogen sulphide, an acid salt is formed.

NaOH(aq) + H₂S(aq) NaHS(aq) + H₂O(l)

When excess sodium hydroxide is used sodium sulphide, a normal salt is formed.

2NaOH(aq) + H₂S(aq)  Na₂S(aq) + 2H₂O(l)

Pollution of the Atmosphere by Compounds of Sulphur

Sulphur compounds especially sulphur(IV) oxide and hydrogen sulphide, are among the major atmospheric pollutants. Sulphur(IV) oxide is usually emitted into the atmosphere when sulphur containing fuels are burnt. Some sulphur(IV) oxide is also emitted during the extraction of metals such as copper and in the manufacture of sulphuric(VI) acid. In the atmosphere sulphur(IV) oxide dissolves in water to form sulphuric(IV) acid.

SO₂(g) + H₂O(l)  H₂SO₃(aq)

The sulphuric(IV) acid is then oxidised by atmospheric oxygen to sulphuric(VI) acid, which comes down as acid rain or acid fog. These have serious environmental effects. These include:

• Stunted growth in plants due to loss of chlorophyll from plants’ leaves.
• Death of plants as a result of defoliation.
• Destruction of aquatic life in acidified lakes.
• Corrosion of stone work on buildings.
• Corrosion of metallic structures.
• Leaching of minerals in the soil.
• Irritation of the respiratory system

Review Exercises

1. 2006 Q 6

In an experiment to study the properties of concentrated sulphuric acid, a mixture of the acid and wood charcoal was heated in a boiling tube.

• Write the equation of the reaction that took place in the boiling tube. (1 mark)

• Using oxidation numbers, show that reduction and oxidation reactions took place in the boiling tube.                                                 (2 marks)

2. 2006 Q 16

When hydrogen sulphide gas was bubbled into an aqueous solution of iron (III) chloride, a yellow precipitate was deposited.

• State another observation that was made.          (1 mark)

• Write an equation for the reaction that took place.           (1 mark)

• What type of reaction was undergone by hydrogen by hydrogen sulphide in this reaction?                                                                                                                                      (1 mark)

3. 2006 Q 27 P1

Study the flow chart below and answer the questions that follow.

• Name reagent z.                                                                              (1mark)

• Describe the process which takes place in step 2.             (1mark)

• Identify the white solid.             (1mark)

4. 2006 Q 4 P2

• The diagram below shows some processes that take place during the industrial manufacture of sulphuric acid.

• Write the equation for the reaction in which sulphur dioxide gas is produced.                                         (1 mark)
• Why is it necessary to keep the gases pure and dry?     (1 mark)

• Describe the process that takes place in chamber G.     (1 mark)

• Name the gases that escape into the environment. (1 mark)

• State and explain the harmful effect on the environment of one of the gases named in (iv) above                             (1 mark)

• Give one reason why it is necessary to use a pressure of 2-3 atmospheres and not more.             (1 mark)

• (i) Complete the table below to show the observations made when concentrated sulphuric acid is added to the substances shown.      (2 marks)

(ii) Give reasons for the observations made using:

1. iron fillings  (1 mark)
2. Crystals of white sugar. (1 mark)

• Name one fertilizer made from sulphuric acid. (1 mark)

• Suggest a reason why BaSO₄(a pigment made from sulphuric acid) would be suitable in making paint for cars.                                  (1 mark)

5. 2007 Q 30 P1

Below is a sketch of a graph showing the change in viscosity? (Ease of flow) with temperature when solid sulphur is heated.

Describe what happens to the sulphur molecules when sulphur is heated from 150 °C to about 200 °C.                                                                                                           (2 marks)

6. 2008 Q 8 P1

• State the observation made at the end of the experiment when a mixture of iron powder and sulphur is heated in a test tube.                                (1 mark)
• Write an equation for the reaction the product in (a) above and dilute hydrochloric acid.                                           (1 mark)
• When a mixture of iron powder and sulphur is heated, it glows more brightly than that of iron fillings and sulphur. Explain this observation.                               (1 mark)

7. 2008 Q 9 P1

Zinc reacts with both concentrated and dilute sulphuric (VI) acid. Write equations for the two reactions.                                                                                                         (2 marks)

8. 2008 Q 30 P1

Crude oil contains sulphur.  What would be the effect to the environment of using fuel containing sulphur?                                                                                                             (1 mark)

9. 2009 Q 22 P1

A student added very dilute sulphuric (VI) acid to four substance and recorded the observations shown in the table below.

For which tests are the observations wrong? Explain.                          (3 marks)

10. 2010 Q 11 P1 ,2016 Q26 P1

Hydrogen sulphide is a highly toxic and flammable gas. It is normally prepared in a fume chamber.

• Name two reagents that can be used to prepare hydrogen sulphide in the laboratory.                             (1 mark)
• One of the uses of hydrogen sulphide is to produce sulphur as shown in the following equation;

2H₂S(g) + SO₂(g)   3S(s) + 2H₂O(l)

Identify the reducing agent in this reaction and give a reason for your answer.                                                                                                                                                      (1 mark)

• Other than production of sulphuric (IV) acid, state one commercial use of sulphur.                             (1 mark)

11. 2011 Q 17 P1

The set up below was used to prepare a gas and study some of its properties.

Study it and answer the questions that follow:

• State and explain the observations made in the.
  1. tube labelled A;    (1 mark)
  2. beaker labelled B.                                                                   (1 mark)
• State one precaution that should be taken when carrying out this experiment.                                         (1 mark)

12. 2011 Q 1 P2

The flow chart below shows some of the processes involved in large scale production of sulphuric (VI) acid. Use it to answer the questions that follow.

• Describe how oxygen is obtained from air on a large scale.               (3 marks)

• (i) Name substance A.                                                                                  (1 mark)

(ii) Write an equation for the process that takes place in the absorption

chamber                                                                                                          (1 mark)

• Vanadium (V) Oxide is a commonly used catalyst in the contact process.
• Name another catalyst which can be used for this process.                       (1 mark)
• Give two reasons why vanadium (V) Oxide is the commonly used catalyst.                                                                                                                                             (2 marks)

• State and explain the observation made when concentrated sulphuric acid is added to crystals of copper (II) sulphate in a beaker.                            (2 marks)

• The reaction of concentrated sulphuric (VI) acid with sodium chloride produces hydrogen chloride gas. State the property of concentrated sulphuric (VI) acid illustrated in this reaction.                                                                                              (1 mark)

• Name four uses of sulphuric (VI) acid.                                              (2 marks)

13. 2012 Q18 P1

Acidified potassium manganate (VII) solution is decolourised when sulphur (IV) oxide is bubbled through it. The equation for the reaction is given below.

 2H₂O (l) + 5SO₂(g) +2KMnO₄(aq  K₂SO₄(aq) + 2MnSO₄(a + 2H₂SO₄(aq)

• Which reactant is oxidised? Explain.                                                                  (2 marks)

• Other than the manufacture of sulphuric (VI) acid, state other use of sulphur (IV) oxide                                                                                                                                (1 mark)

14. 2013 Q12 P1

• What would be observed if sulphur (IV) oxide is bubbled through acidified potassium manganate(VII)?                   (1 mark)

• In an experiment, sulphur (IV) oxide was dissolved in water to form solution L.
• What would be observed if a few drops of barium nitrate solution were immediately added to solution L?                                                                                   (1 mark)
• Write an ionic equation for the reaction that occurred between solution L and aqueous barium nitrate in (b) (i) above.                                                                      (1 mark)

15. 2013 Q3 P2
    • The diagram below shows the Frasch process used for extraction of sulphur. Use it to answer the question that follows.

• Identify X.                                                                                                       (1 mark)
• Why is it necessary to use superheated water in this process? (1 mark)
• State two physical properties of sulphur that makes it possible for it to be extracted by this method.                                       (2 marks)

• The diagram below shows part of the process in the manufacture of sulphuric (VI) acid. Study it and answer the questions that follow.

• Write an equation for the formation of sulphur (IV) oxide from sulphur. (1 mark)
• What is the role of concentrated sulphur (VI) acid in chamber A?            (1 mark)
• Name two catalysts that can be used in the catalytic chamber B.            (2 marks)
• State two roles of the heat exchanger. (1 mark)

• Explain one way in which sulphur (IV) oxide is a pollutant                                           (1mark)

• What observation will be made when a few drops of concentrated sulphuric (VI) acid are added to crystals of sugar? Explain your answer.                                                                       (1 mark)

16. 2014 Q11 P1

Study the flow chart below and answer the questions that follow.

Identify Z and M.                                                                                                         (2 marks)

17. 2014 Q20 P1

In the contact process, during the production of sulphur (VI) oxide, a catalyst is used. Give two reasons why vanadium (V) oxide is preferred to platinum.                                                                                                                                                                                               (2 marks)

18. 2015 Q17 P1

• One of the allotropes of sulphur is rhombic sulphur, name the other allotrope.                                                                                                                                                                   (1 mark)
• Concentrated sulphuric (VI) acid reacts with ethanol and copper.

State the property of the acid shown in each case.                                       (2 marks)

• Ethanol
• Copper ………………………………………………………………………………..

19. 2015 Q5 P2

• The set up below can be used to generate a gas without heating. This occurs when substance M reacts with solid N.

• Complete the table below giving the names of substance M and solid N if the gasses generated are chlorine and sulphur (IV) oxide.                                (2 marks)
• Complete the diagram above to show how a dry sample of sulphur (IV) oxide can be collected.              (2 marks)

• Describe two chemical methods that can be used to test the presence of sulphur (IV)oxide.                                  (3 marks)
• Other than the manufacture of sulphuric (VI) acid, state two uses of sulphur (IV) oxide.                                                                                                                                   (2 marks)

20. 2017 P1 Q7.

A sample of water is suspected to contain sulphate ions. Describe an experiment that can be carried out to determine the presence of sulphate ions.                                      (3 marks)

21. 2017 P2 Q3 (a)

A student used Figure 2 to investigate the action of dilute sulphuric (VI) acid on some metals.

Beaker I and II contained equal volumes of dilute sulphuric (VI) acid. To beaker I, a clean iron rod was dipped and to beaker II, a clean copper rod was dipped.

• Why was it necessary to clean the metal rods?          (1 mark)
• Describe the observations made in each beaker.

Beaker I:                                                                                                         (1 mark)

Beaker II:                                                                                                        (1 mark)

• Explain the observations in (a) (ii).          (2 marks)

22. 2018 P1 Q 4.

One of the allotropes of sulphur is rhombic sulphur.

• Name the other allotrope of sulphur. (1 mark)

• Draw a diagram to show the shape of the allotrope named in (a) above.                               (1 mark)
• Write an equation for the reaction between concentrated sulphuric(VI) acid and sulphur.                                           (1 mark)

23. 2019 P1 Q9.

Sulphur(IV) oxide is prepared in the laboratory using the set-up in Figure 3.

Study it and answer the questions that follow.

• Identify substance F. (1 mark)
• Write an equation for the reaction that takes place in the flask.          (1 mark)
• State the purpose of liquid G.                                                             (1 mark)

NATIONAL INTERGRATION UNITY AND CONFLICT RESOLUTION

23. a) State five factors that promote national unity in Kenya.

• Constitution
• Education
• National language
• Social economic interactions
• Equal distribution of resources
• National philosophies
• National symbols of unity e.g. National flag

Any 5 x 1 = 5 marks

1. b) Explain five methods of conflict resolution.

• Negotiation – discussion between two parties or people who are trying to reach an agreement.
• Arbitration – This is provided by the Kenyan laws. Arbitrators.
• Diplomacy/conciliation – negotiations between individuals to create understanding and room for reconciliation.
• Legislation – passing of laws that controls conflicts. It criminalizes activities that lead to conflicts.
• Traditional society – elders of communities raising their experience to resolve a conflict.
• Religious action – Religious figures are called upon to resolve political, social & economic conflicts and give guidance on the emerging social trends and issues.
• Court action/litigation – parties take other parties to court for arbitration.
• Policing – used to maintain law and order. Presence of police help to control crime that bring about conflicts.
• International agreements – International agreement on security or sharing of Natural resources e.g. Egypt & Kenya on waters of R. Nile.
• Mediation – A situation where a person who is not involved in a dispute tries to reach two conflicting parties reach an agreement.

Any 5 x 2 = 10 marks

ANS 23 DIST 1

11.What is conflict resolution?   (1mk)

• refers to the process of settling disputes. 1×1 = 1mk

ANS 11 DIST 2

14. Give the main reason why Kenya’s celebrate Kenyatta day as a national holiday

• To commemorate the day Kenyatta and other leaders of KAU were arrested by colonial government
• To remind us of the sufferings and blood shed by our people in the struggle for independence

1 x 1 = 1mk

ANS 14 DIST 3

12. Give one way in which the institution of the presidency promotes National Unity (1mk)

–           The President as head of state and government unites all Kenyas.

• All Kenyans look upto one President for protection.             1 x 1 = 1mk

ANS 12 DIST 6

12. State one way in which the Kenyan constitution promotes national unity. ( 1 mk)
13. i) Guarantees equal opportunities for all Kenyans.
14. ii) Provide protection to individuals against any form of discrimination / bill of right.

iii)       Provide for unitary government.                                                        ( Any 1 x 1 = 1 mk)

ANS 12 DIST 7

15. One way in which the constitution promotes national unity

-Guarantees equal opportunity to all Kenyans

-Provides protection to individuals against any form of discrimination     2×1=2mks

18. One level of conflict (1mk)

-Individual verse individual

-Group verse group

-Individual verse state

-Group verse state

-State verse state     1×1= 1mk

24. b) Explain five reasons why national integration is important

-To develop national unity in spite of the differences if each communities

-For economic and social development as people unite their effort             towards the development of various    economic activities

-To promote peaceful co-existence of different tribes as people accept their culture differences /    intercultural tolerance

-Enables the country to develop a sense of national direction as national goals are             communicated  to the             people and also enable people todevelop unified goals for the             nation

-Enables the country to achieve an easier, more efficient and accurate communication

-Reduces conflicts based on ethnicity religion / race hence less wars, deaths and property destruction.

-Ensures political stability / security

-Eliminates suspicion among citizen of different tribes /religion /political thus eliminates tribalism, nepotism or corruption.

– Encourages a sense of nationalism and patriotism       (5×2=10mks)    well explained

ANS 15, 18, 24b DIST 8.

14. Why is it important to have cultural activities in Kenya today.             (1mk)
15. i) They entertain people
16. ii) They educate the masses

iii)       They unite the people

1. iv) They promote patriotism
2. v) They create employment
3. vi) They preserve African culture.                                     Any 1×1 = 1mk
4. Celebration for gaining internal sef-governance/Madaraka Day.

Give the major historical significance of first June in Kenya.                                           (1mk)

ANS 14, 16 DIST 9

13. State one way in which the Kenyan constitution promotes national unity 1mk)
14. It ensures equal opportunities to all Kenyans
15. It provides protection to individuals against any form of discrimination
16. It provides for a unitary system of government
17. All Kenyans are subjected to the same constitution of law Any 1×1 = 1mark

1. Give two ways through which conflicts can  be resolved peacefully          (2mks)

1. Diplomacy / negotiation
2. Arbitration
3. Litigation
4. Mediation
5. Legislation / parliament passes laws to control conflict Any 2×1 = 2 marks

1. a) Identify five symbols of national unity in Kenya                                          (5mks)

1. National flag – signifies one nation
2. National award
3. National anthem
4. Loyalty pledge
5. Court of arms

5×1 = 5marks

1. b) Discuss the steps that have been taken by the Kenyan government to promote national integration since independence                (10mks)
2. Development of national symbols e.g. flag, anthem etc
3. Declaring Kiswahili a national language
4. Promotion of Harambe spirit which unites all Kenyans and promotes a sense of belonging
5. Introduction of The Nyayo philosophy of peace, love and liberty
6. Use of one constitution which promotes equality of all Kenyans before the law
7. Promotion of games, sports and cultural activities within the general public and in leaning institutions
8. Abolition of ethnic organizations and groupings
9. Promotion of a National Public Service where civil servants can serve anywhere in the country

Any 5×2 = 10marks

ANS 13, 14, 22 DIST 10

2.i)  It encourages the rich and the poor to exploit other members of the society.

1. ii) It widens the gap between the rich and the poor in the society thus creating enemity    and

iii) It leads to mismanagement of resources / economy .

1. iv) It breeds other vices such as hatred , individualism and injustice.
2. v) It promotes a skewed / unbalanced  distribution of national resources.(1 x 1 = 1mk)
3. a) –   Greed

–   Exploitation of the poor by the rich.

–   Nepotism

–   Tribalism

–    Racism

–    Irresponsible statements by leaders.

–    Religious differences

–    Thirst for power

–    Political differences / ideological differences

–    Trade union disputes / industrial disputes.                 (5 x1=5mks)

1. b) i) Negotiation – creation of understanding between 2 parties.
2. ii) Arbitration – disagreement is solved by a neutral person

iii) Mediation – involves a third party who is not part of the conflict.

1. iv) Court settlement – dispute is taken to court/ litigation.
2. v) Out of court settlement – dispute is handled out of court
3. vi) Traditional society / use of elders – involves use of customary law by the elders.

vii) Religious action – Handled by church elders.

viii) Policing – presence of the police help control crime.

1. ix) Compromise – Opposing parties take a middle ground. (5×2=10mks)

ANS 2, 22 DIST 11

1. State two importance of national integration.
2. i) It create unity for national integration
3. ii) It promotes peaceful co-existence and stability i.e. different tribes and races.

iii) It provides national direction as it sets national goods.

iv ) It promotes patriotism and nationalism.

1. v) It enhances communication among the people since it involves an official language of

ANS 7 DIST 13

24.(a)  State five ways in which conflicts can be prevented in Kenya.                              (5mks)

• Able leadership
• Respecting other peoples rights and freedoms
• Having a good constitution
• Respecting the principles of democracy
• Having proper electoral process
• Equitable/fair distribution of resources.
• Maintenance of law and order
• Having a responsible media.

5 x 1 = 5mks

ANS 24a DIST 14

9. – Individual vs Individual

– Individual vs state

– Group vs state

– state vs state 2×1 = 2mks

ANS 9 DIST 16

22b.- Constitution

– National language

– Education

– Fair distribution of resources

– One president

– Games and sports

– Social and economic interactions

– Employment opportunities

– National motto

– Urbanization

– Symbols of national unity

– National activities and holidays

– Mass media                                                                                                  (6 x 2=12mks)

ANS 22a DIST 17

20b. Describe six steps that can ensure a successful and peaceful resolution of

conflicts (12 mks)

• Identification of the conflict – the conflicting parties should recognize

that a conflict exists

(ii)       Arbitrator must be accepted by all

• Diagnosis on the causes of the conflict
• Scrutinizing of the grievances
• Determination of the extent to which the conflict has progressed
• Examination of options for conflict resolution, aiming at the best long term solution
• Implementation of the solution by the parties involved
• Both parties to accept the outcome, failure to which an alternative should be sought.
• The arbitrator should make a follow up.

443 – AGRICULTURE

GENERAL OBJECTIVES

The Secondary Agriculture course aims to:

1. develop an understanding of agriculture and its importance to the family and the nation;
2. promote interest in agriculture as an industry and create awareness of opportunities existing in agriculture and related sectors;
3. demonstrate that farming is a dignified and profitable occupation;
4. enhance skills needed in carrying out agricultural practices;
5. provide a background for further studies in agriculture;
6. develop self-reliance, resourcefulness and problem solving abilities in agriculture;
7. develop occupational outlook in agriculture;
8. enable schools to take an active part in national development through agricultural activities;
9. create awareness of the role of agriculture in industrial and technological development;
10. enhance understanding of the role of technology and industrialization in agricultural development;

12. promote agricultural activities which enhance environmental conservation;
    12. promote consciousness of health promoting activities in agricultural production.

1.0.9 INTRODUCTION TO AGRICULTURE

1.1.0 Specific Objectives

By the end of the topic, the learner should be able to:
a) define agriculture;
b) state the main branches of agriculture;
c) describe farming systems;
d) describe farming methods;
e) explain the role of agriculture in the economy.

1.2.0 Content
1.2.1 Definition of agriculture.
1.2.2 Branches of agriculture.

• Crop-farming (Amble farming) – Field crops; Horticulture – Floriculture (flower farming), Olericulture (vegetable farming) and Promoculture (fruit farming).
• Livestock farming: Pastoralism (mammalian livestock farming); Fish farming; Apiculture (Bee keeping); Poultry keeping
• Agricultural economics
• Agricultural engineering.

1.2.3 Systems of fanning; Extensive, Intensive, Large scale, and Small sea Study these under the following headings; Meaning, Advantages and

Disadvantages.

1.2.4 Methods of farming: Mixed farming; Nomadic Pastoralism; Shifting cm Organic farming; Agro-forestry.
1.25 Roles of agriculture in the economy: Food supply; Source of employment Foreign exchange earner; Source of raw materials for industries; Provision market for industrial goods; Source of capital.

2.0.0 FACTORS INFLUENCING AGRICULTURE

2.1.0 Specific Objectives

By the end of the topic, the learner should be able to:
a) explain the human factors influencing agriculture;
b) explain biotic factors influencing agriculture;
c) explain how climatic factors influence agriculture;
d) define soil;
e) describe the process of soil formation g) determine soil constituents;
h) classify soils by physical characteristics;
i) explain chemical properties of soils;
j) relate crop and livestock distribution to soils in different regions.

2.2.1 Content
2.2.2 Human factors: Levels of education and technology; Health — HIV/AIDS and health in general; Economy (include liberalization); Transport and communication; Market forces (local and international); Government policy; Cultural and religious beliefs.
2.2.3 Biotic Factors: Pests, Parasites, Decomposers, Pathogens, Predators, Pollinators
Nitrogen fixing bacteria

2.2.4 Climatic Factors

• Rainfall: Intensity, Reliability, Quantity; Distribution.
• Temperature: – How topography and altitude affect temperature.

– How temperature influences crop and livestock production.

• Wind: Evapotranspiration, Lodging, Pollination, Seed dispersal, Soil erosion
• Light — Intensity, Duration — long, neutral and short day plants, Wavelength

Note: – Each factor to be discussed with respect to Land potentiality, Crop production, Livestock production, Crop and livestock distribution in Kenya.

2.2.5 Edaphic factors: Definition of soil, Soil formation, Soil profile (definition, characteristics of different soil layers, difference between soil formed in situ and depositions, Soil depth and its influence on crop production).

• Soil constituents: Constituents, Importance of each constituent, Physical properties of soil.
• Soil Structure — definition, types, influence on crop production.
• Soil texture —definition, soil textural classification, influences on crop growth and production, porosity, capillarity, drainage and water retention capacity.
• Soil colour
• Chemical properties of soil -Soil pH, PH influence on crop growth and production, effects of pH on mineral availability.

3.0.0 SOIL AND WATER CONSERVATION

3.1.0 Specific Objectives

By the end of the topic, the learner should be able to:
a) define soil erosion;
b) explain the various factors that influence erosion;
c) list the agents of erosion;
d) describe various types of erosion;
e) describe various methods of erosion control;
1) carry out soil erosion control measures;
g) describe water harvesting and conservation techniques;
h) describe micro-catchments and their uses;
i) design and construct a micro-catchment.
3.2.0 Content

3.2.1 Soil erosion – definition

3.2.2 Factors influencing erosion: land use and ground cover, topography-gradient and
length of slope (horizontal and vertical intervals).

• Soil type and condition (Erodability)
• Rainfall intensity (Erosivity)

3.2.3 Agents of erosion: Water, Wind, Human beings and Animals.

3.2.4 Types of erosion: Splash/rain drop, Sheet, Rill, Gully (gully formation, types of gullies), River bank, Solifluction, Landslides.
3.2.5 Biological/cultural control: Grass strips, Cover crops, Contour farming and strip cropping, Mulching, Afforestation/forestation.
.2.6 Physical/structural control: Stone lines, Filterstrips, Trashlines, Terraces (level, graded, broad-based, narrow-based. Bench, fanya juu, fanya chini), Bunds, Cutoff-drains/Diversion ditches, Gabions/porous dams, Ridging.
3.2.7 Water harvesting: Roof catchments, Rock catchments, Weirs and dams, Ponds, Retention ditches/Level terraces.
3.2.8 Micro-catchments: Types, Uses, Laying out and construction methods.
4.0.0 WATER SUPPLY, IRRIGATION AND DRAINAGE

4.1.0 Specific Objectives
By the end of the topic, the learner should be able to:
a) state the sources of water for the farm;
b) describe collection, storage, pumping and conveyance of water;
c) describe water treatment and explain its importance;
d) define irrigation;
e) explain the importance of litigation;
1) describe methods of irrigating land;
g) list the equipment used in litigation;
h) grow a crop through irrigation;
1) cart: out maintenance oil drilling equipment and facilities;
j) define drainage;
k) explain the importance of drainage;
1) describe the methods of drainage;
m) explain how agricultural activities pollute water and how this can be prevented;

4;2;0 Content

4;2;l Water supply: Sources of water4 Collection and storage of water Pumps and pumping, Conveyance of water (Piping types of pipes Choice of pipes, Canals, Transportation in containers), Water treatment (Meaning, Methods, Importance), Uses of water on the farm
4;2;2 litigation: Definition, Importance (include irrigation as a method of land reclamation) Methods (surface4 subsurface, overhead, drip).

Note.’- the advantages and the disadvantages of each.

Maintenance practices of each irrigation system.
4;2i Project on crop production through any method of Irrigation.
414 Drainage: Definition, Importance (include as a method of land ret lamatioii)5
Methods of drainage (surface, sub-surface, pumping, planting of appropriate trees);
4;2; Water Pollution: Meanings Agricultural practices that pollute water, Methods of pollution prevention and control.

SOIL FERTlLITY  I (Organic Manures)

Specific Objectives

By the end of the topic5 the learner should be able to:
a) define soil fertility;
b) explain how soil fertility can be maintained; describe how soil loses fertility;
l) define and distinguish organic matter manure and humus;
e) explain the Importance of organic matter In the soil

1. f) describe the different organic manures;
   g) prepare compost manure

Soil fertility Definition4 How soil loses fertility, Maintenance of soil fertility. Organic Manure Organic matter and humus4 Importance of organic matter in the soil, types of organic manures – green manure, Famyard  manure Compost manure

Note; For each type, describe its preparation, advantages and disadvantages and u4c.
5.2.3 Compost manure: Meaning, Materials used and materials to avoid, Preparation methods and procedure (Heap and Pit).

6.0.0 SOIL FERTILITY: II (INORGANIC FERTILIZERS)

6.1.0 Specific Objectives

By the end of the topic, the learner should be able to:
a) list the essential elements;
b) classify’ the essential elements;
c) state the role of each macro-nutrients, micro-nutrients;
d) describe the deficiency symptoms of the macro-nutrients, micro-nutrients;
e) identify and classify fertilizers;
1) describe the properties of various fertilizers;
g) describe soil sampling and testing procedures;
h) use appropriate methods of fertilizer application;
i) calculate fertilizer application rates;
j) explain how soil acidity and alkalinity affect crop production.

6.2.0 Content

6.2.1 Essential elements
• Macro-nutrients: carbon, hydrogen and oxygen, fertilizer elements (N.PK.), liming elements (Ca, Mg), Sulphur, Role of macro-nutrients in crops,
Deficiency symptoms of macro-nutrients ts in crops
• Micro-nutrients: Role of micro-nutrients in crops, Deficiency symptoms of micro-nutrients in crops,
6.2.2 Inorganic fertilizers: Classification of fertilizers, Identification of fertilizers, Properties of fertilizers, Methods of fertilizer application, Determination of fertilizer rates..
6.2.3 Soil sampling: Meaning, Soil sampling methods and procedures, Sites to avoid, Preparation and Procedure of sending soil for testing.
6.2.4 Soil testing: Meaning, Importance, Testing for pH, How soil pH affects crop production.

Note Learners to make a table showing optimum pH range for various crops.

7.0.0 FARM TOOLS AND EQUIPMENT

7.1.0 Specific Objectives

By the end of the topic, the learner should be able to:
a) identify various farm tools and equipment;
b) name parts of various farm tools and equipment;
c) describe the use of various tools and equipment
d) carry out maintenance practices on tools and equipment.,

7.2.0 Content

7.2.1 Garden tools and equipment
7.2.2 Workshop tools and equipment: Woodwork tools and equipment, Metalwork tools and equipment.
7.2.3 Livestock production tools and equipment
7.2.4 Plumbing tools and equipment
7.2.5 Masonry tools and equipment.

Note: Study the above tools under the headings: Name and uses, Parts and uses, Maintenance practices
See the appendix for the list of tools and equipment to be studied.
8.0.0 CROP PRODUCTION I (LAND PREPARATION)

8.1.0 Specific Objectives

By the end of the topic, the learner should be able to:
a) explain the importance of land preparation;
b) describe the various types of cultivation;
c) relate cultivation operation to correct tools and or implements;
d) prepare a piece of land ready for crop production.
8.2.0 Content
8.2.1 Land preparation: Definition, Importance.
8.2.2 Operations in land preparation: Clearing land before cultivation (importance include clearing as a method of land reclamation; Methods and equipment.

• Primary cultivation: Definition and importance, Timing, Choice of tools implements
• Secondary cultivation: Definition and importance, Number of operations, Relating final tilth to the intended planting material.
• Tertiary operations: Ridging, Rolling, Leveling

Note: For each operation: give reasons and explain how it is carried out.
• Sub-soiling: Meaning, Importance, Equipment used.
8.2.3 Minimum tillage: Definition, Importance, Practices.
9.0.0 CROP PESTS AND DISEASES

9.1.0 Specific Objectives

By the end of the topic, the learner should be able to:
a) define pest and disease;
b) state the main causes of crop diseases;
c) describe the harmful effects of crop pests and diseases;
d) identif’ and classify some of crop pests and diseases;
e) carry out general disease and pest control measures.
9.2.0 Content
9.2.1 Pests: Definition, Classification of pests (mode of feeding, Crops attacked, Stage of growth of crop attacked, Field and storage pests), Identification of common pests, Harmful effects of pests, est control measures.
9.2.2 Diseases: Definition, Classification of diseases according to cause, Identification of common diseases, Disease control, Harmful effects of diseases, Disease control measures.
10.0.0 CROP PRODUCTION II (PLANTING)

10.1.0 Specific Objectives

By the end of the topic, the learner should be able to:

1. a) state the correct planting materials for various crops;
   b) select and prepare planting materials;
   c) determine the optimum time of planting;
   d) state the factors which determine the depth of planting;
   e) describe the planting procedures for different crops;
   f) state the factors that determine seed rate, spacing and plant population;
   g) calculate plant population.

10.2.0 Content

10.2.1 Types of planting materials

• Seeds: Description, Advantages, Disadvantages,
• Vegetative materials: Description, Advantages, Disadvantages
• Plant parts used for vegetative propagation: Slips, Splits, Bulbils, Crowns,

Suckers, Tubers, Vines, Cuttings and setts.
10.2.2 Selection of planting materials: Suitability to ecological conditions (use maize hybrids and coffee varieties as examples), Purity, Germination percentage,
Certified seeds.
.2.3 Preparation of planting materials: Breaking dormancy, Disease and pest control/seed dressing, Seed inoculation, Chitting.
Note: Give appropriate crop examples for each practice.
10.2.4 Planting:

• Timing – factors to consider, advantages of timely planting.
• Methods of planting: broadcasting, row planting, oversowing (refer to pastures), undersowing.

note: Give appropriate crop examples for each method
Plant population:

• Spacing – factors to consider, seed rate
• Calculation of plant population per unit area. : Factors to consider

110,0 CROP PRODUCTION III (NURSERY PRACTICES

11,1,0 Specific Objectives

By the end of the topic, the learner should be able to:
(a) describe a nursery bed;
(b distinguish between a nursery bed, a seedling bed and a seed bed;
(c) state the importance of a nursery bed;
(d) select a suitable site for a nursery
(e) prepare a nursery bed;
(0 establish a nursery bed
(g manage a nursery bed;
(h) transplant crops from a nursery;
(1) bud a seedling;
Q) graft a seedling;
(k) explain the importance of budding, grafting, layering and tissue culture;
(I) describe damage caused by animals on tree seedling and how to prevent it

11 2,0 Content

Nursery bed:

Definition, Difference between a nursery bed, seedling bed and a seed bed, importance, Site selection, nursery establishment (vegetable nursery, tree nursery, vegetative propagation nursery (tea as an example)
use of sleeves and other innovations for growing young plants making and using seedling boxes for growing young plants preparation of rooting medium
preparation of cuttings.

11,22 Routine management in raising seedlings: Seed drilling, Mulching, Watering, Shading, Pricking out, Hardening off, Weed control, Pest control, Disease control,

I I,23 Budding: Meaning, Methods and procedure, Appropriate plants, Appropriate tools and materials.
Note: Learners to practise budding of orange scions on lemon root-stocks or other appropriate plants,
II l4 Grafting: Meaning, Methods and procedure, Appropriate plants, Appropriate tools
and materials.
Note: Learners to practice grqlIing on appropriate fruit trees.
1124 Importance of budding and grafting.
11.2.6 Layering: Methods, Importance, Appropriate crops/plants tbr layering, Materiah used in layering.

11.2.7 Tissue culture fbr crop propagation
11.2.8 Transplanting of vegetable seedlings from nursery to seedbed: Timing, Procedure and precautions

11.2.9 Transplanting of tree seedlings: Timing, Digging appropriate holes, Planting including firming and watering, Protecting the seedlings after transplanting
– Shading
– Damage caused by animals on tree seedlings and how to prevent it.

12.0.0 CROP PRODUCTION IV (FIELD PRACTICES I

12.IS Specific Objectives

By the end of the topic the learner should be able tot
(a) define crop rotation;
(I,) state the importance of crop rotation;
(c) draw a crop rotation programme;
(d) distinguish terms used in crop fanning;
(e) state the importance of mulching in crop production;
(f) describe the importance of various routine field practices In crop production;
(g) catty out various field practices;
(h) state the correct stage rot harvesting various crops;
(i) describe harvesting practices for various crops

122O Content

12.2.1 Crop rotation: Definition, Importance, Factors influencing crop rotation, Rotational programmes.

12.12 Terms used in crop production; Monocropping, intercropping, Mixed cropping
12.2.3 Mulching; Meaning, Importance, Types of mulching materials (organic, inorganic), Advantages and disadvantages of mulching materials.

12.24 Routine field practices: Thinning, Rogueing; Gapping, Training Pruning(  Coffee single and multiple stem, capping, de-suckering, changing cycles; banana stool management; pyrethrum – cutting back), Earthing up, Crop protection (weed control pests and disease control

Note:- Study the importance and timing of each activity and the appropriate kite crops.
12.2.5 Harvesting: Stage and timing of harvesting, Methods of harvesting, Precautions during harvesting

12.2.6 Post = harvesting practices: Threshing/shelling, Drying, Cleaning, Sorting and grading, Dusting, Packaging.
12.2.7 Storage: Importance, types of storage, Preparation of *tore.

13.0.0 CROP PRODUCTION V (VEGETABLES)

13.1.1 Specific Objectives

By the end of the topic, the learner should be able to:

(a) grow a vegetable crop from nursery establishment to harvesting;
(b) keep a crop production records;
(c) market farm produce.
13.2.0 Content
13.2.1 Vegetable crops: Tomatoes (use varieties that require pruning and staking), Carrots, Onions, Cabbages/Kales.

14.0.0 CROP PRODUCTION VI (FIELD PRACTICES II

By the end of the topic, the learner should be able to:
(a) describe management practices in crop production;
(b) carry out management practices for a given crop;
(c) explain how crop production can be an economically lucrative activity.
14.2.0 Content
14.2.1 Production of: Maize/millet/sorghum, Beans
• Discuss the above crops under the following:-
– Meaning of hybrids, composites and cultivars
– Selecting best hybrids, composites or cultivars for given climatic regions.
– Raising of a maize/sorghum/millet and bean crop from seed bed preparation to harvesting.
– Keeping records in production of maize/sorghum millet and beans.
14.2.2 Rice production: Land preparation, Water control, Use of flooding in rice-field, Fertilizer application, Weed control.
14.2.3 Harvesting of the following crops: Cotton, Pyrethrum, Sugar cane , Tea, Coffee Under the following: Stage of harvesting; ; Method and procedure of harvesting; Precautions in harvesting.
Note: Compare cost of production with value of product for maize/sorghum/ millet and beans
15.0.0 FORAGE CROPS

15.1.0 Specific Objectives

By the end of the topic, the learner should be able to:

(a) define and classify pastures;
(b) identify forage crops;
(e) describe the ecological requirements of forage crops;
(d) describe the establishment and management of pastures and fodder;
(e) describe forage utilization and conservation.
15.2.0 Content
15.2.1 Pastures: Definition, Classification, Establishment, Management, Utilization – grazing systems -rotational grazing, herding, zero grazing.
15.2.2 Fodder crops: ; Napier/bana grass; Guatemala grass; Sorghum; Kale; Edible cana Lucerne; Clovers; Desmodium; Mangolds; Agro-forest trees/bushes used as fodder.
Nb. Study the above crops under the following: Ecological requirements, Establishment and management, Production per unit area, Utilization.
15.2.3 Forage conservation: Hay making, Silage making, Standing hay.
16.0.0 WEEDS AND WEED CONTROL

16.1.0 Specific Objectives

By the end of the topic, the learners should be able to:
(a) define a weed;
(b) identify weeds;
(e) classify weeds;
(d) explain the characteristics which make the weeds competitive;
(e) describe ways of controlling weeds;
(f) state harmful effects of weeds;
(g) control weeds;
(h) exercise safety measures to oneself, to crops and the environment while controlling weeds.
16.2.0 Content
16.2.1 Weeds: Definition of a weed, Weed identification and classification, Competitive ability of weeds (Appropriate examples for each ability), Harmful effects of weeds (appropriate examples for each effect).
Note:- See appendix Resources B on weeds to be studied.
16.2.2 Weed control methods: Chemical weed control (classes of herbicides, methods of application and safety measures in use of chemicals), Mechanical weed control, Cultural weed control, Biological weed control, Legislative control.
17.0.0 AGRO-FORESTRY

17.1.0 Specific Objectives

By the end of the topic, the learner should be able to:
(a) define agro-forestry;
(b) state the importance of agro-forestry;
(c) describe various forms of agro-forestry;
(d) explain the importance of trees;
(e) select appropriate trees for different uses;
(f) describe tree nursery management and transplanting;
(g) explain routine tree management;
(h) select appropriate sites for trees in the farm and other areas;
(i) describe various methods of tree harvesting.

17.2.0 Content

17.2.1 Definition of agro-forestry: Forms of agro-forestry
17.2.2 Importance of agro-forestry
17.2.3 Importance of trees and shrubs: Important trees and shrubs for particular purposes; Trees and shrubs to avoid at certain sites and reasons.
17.2.4 Tree nursery: Types of nurseries, Seed collection and preparation, Nursery management, Transplanting.
17.2.5 Care and management of trees: Protection, Pruning and training, Grafting old trees.
17.2.6 Agro-forestry practices: Alley cropping, Woodlots in farms.
17.2.7 Sites for agro-forestry trees: Boundaries, River banks, Terraces, Slopes, Homestead.
17.2.7 Tree harvesting methods.

18.0.0 LIVESTOCK PRODUCTION I (COMMON BREEDS)

18.1.0 Specific Objectives

By the end of the topic the learner should be able to:
(a) state the importance of livestock;
(1,) name various livestock species;
(e) define the terms livestock, breed and type;
(d) describe the various breed characteristics;
(e) state the origin of various livestock breeds;
(f) classify the various breeds into types;
(g) name the external parts of the various livestock species.
18.2.1 Content
18.2.2 Importance of livestock
18.2.3 Livestock species: Cattle (exotic and indigenous), Goats, Sheep, Pigs, Poultry (chicken), Rabbits, Camels.
Discuss each under the following: Breed, origin and characteristics, Type of each breed, External parts of each livestock species, Typical conformation
18.2.4 Terms used to describe livestock in different species by age, sex and use.

19.0.0 LIVESTOCK PRODUCTION III (SELECTION AND BREEDING)

19.1.0 Specific Objectives

By the end of the topic, the learner should be able to:
(a) describe reproduction and;
(b) reproductive systems;
(c) select breeding stock;
(d) describe breeding systems;
(e) identify signs of heat in livestock;
(f) describe methods used in serving livestock;
(g) describe signs of parturition in cattle, pigs and rabbits.

19.2.0 Content

19.2.1 Reproduction and reproductive systems: Cattle and Poultry.
19.2.2 Selection: Meaning; Factors to consider in selecting a breeding stock- Cattle, Sheep, Goats, Pigs, Camels; Methods of selection – mass selection , contemporary comparison, progeny testing.
19.2.3 Breeding: Meaning; Terms used in breeding – dominant and recessive genes, Heterosis (hybrid vigour), Epistasis; Breeding systems – Cross-breeding, Upgrading, Inbreeding, Line breeding, Out-crossing

Note: Discuss under the headings: Definition, Advantages and Disadvantages
19.2.4 Signs of heat in Cattle, Pigs and Rabbits.

Note: Study the oestrus cycle of each of the above.

19.2.5 Methods of service in livestock: Natural mating, Artificial insemination, Embryo transplant.
Note: Discuss advantages and disadvantages of each
19..2.6 Signs of Parturition in Cattle, Pigs and Rabbits.
Note: Learners to handle livestock in appropriate caring manner.

LIVESTOCK HEALTH I (INTRODUCTION TO LIVESTOCK HEALTH)

20.1.0 Specific Objectives

By the end of the topic the learner should be able to:
(a) define health and disease;
(b) describe signs of sickness in animals;
(c) state the predisposing factors of livestock diseases;
(d) categorize animal diseases;
(e) carry out disease control practices;
(fl state the importance of maintaining livestock healthy;
(g) describe appropriate methods of handling livestock.
20.2.0 Content
20.2.1 Health and disease: Definitions; Importance of keeping livestock healthy; Predisposing factors of livestock diseases; Signs of ill-health in livestock.
20.2.2 Classification of livestock diseases by cause.
20.2.3 General methods of disease control
20.2.4 Appropriate methods of handling livestock.

21.0.0 LIVESTOCK HEALTH II (PARASITES)

21.1.0 Specific Objectives

By the end of the topic the learner should be able to:
(a) describe host parasite relationship
(b) identify different parasites;
(c) describe the life-cycle of parasites;
(d) state signs & symptoms of attacks;
(e) explain methods of parasite control in livestock.
21.2.0 Content
21.2.1 Host: Parasite relationship; Effects of parasites on hosts.
21.2.2 External parasites: Ticks, Tsetse flies, Mites, Lice, Fleas, Keds
21.2.3 Internal parasites: Roundworms (Ascaris spp); Tapeworms (Taenia spp); Flukes (Fasciola spp).
Note: The parasites should be studied under the following: -Identification, Livestock species attacked, Part(s) of livestock attacked or inhabited and mode of feeding.
21.2.4 Signs and symptoms of attack.
21.2.5 Describe the life cycles of the following:Roundworm (Ascaris spp); Tapeworm (Taenia spp); Liver fluke (Fasciola spp); Ticks (appropriate example one host, two host , three host)
Note: Indicate whether soft or hard tick
21.2.6 Methods of parasite control giving appropriate example of a parasite for each method.
2.0.0 LIVESTOCK HEALTH III (DISEASES)

22.1.0 Specific Objectives

By the end of the topic, the learner should be able to:
(a) describe causes and vectors of main livestock diseases;
(b) state the incubation period;
(c) describe the signs of each disease;
(d) state the predisposing factors where applicable;
(e) carry out simple control measures of livestock diseases;
(fl state the measures taken to avoid environmental pollution.

22.2.0 Content

22.2.1 Protozoan diseases: East coast fever; Anaplasmosis; Coccidiosis; Trypanosomiasis (Nagana).
22.2.2 Bacterial diseases: Fowl typhoid; Foot rot; Contagious abortion (Brucellosis); Scours; Blackquarter; Mastitis; Anthrax; Pneumonia
22.2.3 Viral diseases: ; rinderpest; Foot and mouth ; Newcastle; Fowl pox; Gumboro; African Swine fever.
22.2.4 Nutritional diseases: Milk fever; Bloat.
All the above diseases should be studied under the following:

• Animal species attacked
• Cause/casual organism/agent and or vector
• Predisposing factors (where applicable)
• Incubation period (where applicable)
• Signs and symptoms of disease
• Simple control measures of the diseases
• Appropriate measures to avoid environmental pollution.

23.0.0 LIVESTOCK PRODUCTION II (NUTRITION)

23.1.0 Specific Objectives

By the end of the topic, the learner should be able to:
(a) identify and classify livestock feeds;
(b) describe digestion;
(c) define terms used to express feed values;
(d) compute a livestock ration;
(e) prepare balanced ration for various livestock;
(0 describe the appropriate livestock handling techniques while feeding.
23.2.0 Content
23.2.1 Livestock nutrition: Feeds and Feeding (identification, classification of feeds, terms used in expressing feed values, computation of livestock rations, preparation of livestock rations); Digestive systems (ruminant eg cattle, and non- ruminant eg pig and poultry); Digestion in cattle, pig and poultry.
23.2.2 Appropriate livestock handling techniques while feeding.
24.0.0 LIVESTOCK PRODUCTION IV (LIVESTOCK REARING PRACTICES)

24.1.0 Specific Objectives

By the end of the topic, the learner should be able to:
(a) describe livestock rearing practices;
(b) carry out livestock rearing practices;
(c) describe appropriate handling techniques of livestock during routine management.

24.2.0 Content

24.2.1 Routine livestock rearing practices: Feeding practices (flushing, steaming up, creep feeding); Parasites and Disease control practices (vaccination, dehorning, hoof trimming, docking, dipping/spraying, dusting); Breeding practices (crutching, tupping and serving, raddling, ringing); Identification; Debeaking; Tooth clipping; Culling: Describe general methods and carry out practicals on cattle, poultry; Castration (open, closed, caponization);

Management during parturition:- pigs, cattle, sheep, goats and rabbits.

24.2.2 Bee Keeping (Apiculture): Importance; Colony; Siting of the apiary and hive; Stocking a bee hive; Management — feeding and predator and pest control; Honey harvesting and processing.

24.2.3 Fish Farming (aquaculture): Importance; Types of fish kept in farm ponds; Management; Harvesting; Processing and preservation.
24.2.4 Appropriate handling of livestock during routine management.

25.0.0 LIVESTOCK PRODUCTION VI (CATTLE)

25.1.0 Specific objectives

By the end of the topic, the learner should be able to:
(a) raise young stock;
(b) describe milk by its components;
(c) describe milk secretion and let-down;
(d) milk using correct procedure and technique;
(e) describe marketing of beef cattle and milk;
25.2.0 Content
25.2.1 Raising young stock: ; Feeding; Weaning ; Housing; Routine practices.
25.2.2. Milk and milking: Milk composition,; Milk secretion and let down; Clean milk production (equipment and materials (include milking machine), cleanliness of the milk man /milk woman, milking procedure (by hand and by machine), Milking techniques); Dry cow therapy.
25.2.3 Marketing of milk
25.2.4 Marketing beef cattle.

26.0.0 LIVESTOCK PRODUCTION V (POULTRY)

26.1.0 Specific Objectives

By the end of the topic, the learner should be able to:
(a) identify parts of an egg;
(b) select eggs for incubation;
(e) describe conditions necessary for artificial incubation;
(d) identify, suitable sources of chicks;
(e) describe broodiness and natural brooding; (fl describe brooder and brooder management;
(g) describe rearing systems;
(h) describe the feeding for each age and category of poultry;
(i) identify stress and vices;
0) state the causes of stress and vices;
(k) state the effects of vices and stress in poultry;
(1) state control measures of vices and stress;
(m) describe marketing of eggs and poultry meat;
(n) select, sort and grade eggs for marketing;
(o) explain how poultry production can be an economically lucrative activity.

26.2.0 Content

262.1 Parts of an egg
26.2.2 Incubation: Meaning; Selection of eggs for incubation; Natural incubation (Signs of broodiness in poultry, Preparation and management of natural incubation); Artificial incubation (management of the incubator).
26.2.3 Sources of chicks
26.2.4 Brooding: ; Meaning; Natural brooding; Artificial brooding (brooder and brooder management, conditions equipment, management of layers and broilers.
26.2.5 Rearing systems: Extensive (free range); Semi-intensive (fold system); Intensive (deep litter and battery cage system.)

Note: Include advantages and disadvantages of each system.
26.2.6 Chicken feeding: Broilers and Layers.
26.2.7 Stress and vices in chicken: Identification; Causes; Control.
26.2.8 Marketing: Eggs —(-include grading of eggs for marketing) and meat.

27.0.0 FARM STRUCTURES

27.1.0 Specific Objectives

By the end of the topic, the learner should be able to:
(a) describe parts of a building;
(b) identify materials for construction;
(c) describe various farm structures and their uses;
(d) describe siting of various structures;
(e) construct and maintain farm structure.
27.2.0 Content
27.2.1 Farm building and structures: Siting; Parts of a building (foundation, wall, roof
27.2.2 Livestock buildings and structures: Crushes; Dips; Spray race; Dairy shed/parlour; Calf pens; Poultry houses and structures (deep litter, Coops, folds/arks, Runs, battery cages); Rabbit hutches/Rubbitry; Piggery/pigs sty; Fish ponds; Silos (for silage); Zero grazing unit; Bee hives.
27.2.3 Farm stores: Feed; Farm produce; Chemical; Machinery; Tools
27.2.4 Green house: Meaning; Construction materials used; Uses.
27.2.5 Fences in the farm: Types of fences and materials used; Uses — advantages and disadvantages; Gates and passes in fences; Fence reinforcement.

Note: Construct any of the following structures: a crush, a beehive, a hutch

28.0.0 FARM POWER AND MACHINERY

28.1.0 Specific Objectives

By the end of the topic, the learner should be able to:
(a) describe various sources of power in the farm;
(b) describe various systems of a tractor;
(c) describe the various tractor drawn implements, their uses & maintenance;
(d) describe the various animal drawn implements, their uses and maintenance;
(e) describe tractor service and maintenance practices.

282.0 Content

28.2.1 Sources of power in the farm: Human ; Animal; Wind; Water; Biomass (wood/charcoal, biogas); Fossil fuel (coal, petroleum, natural gas); Electrical (hydro, geothermal, nuclear, storage battery); Solar.
28.2.2 Tractor Engine: four stroke cycle engine (diesel and petrol); Two stroke cycle engine
28.2.3 Systems of the tractor: Fuel system; Electrical; Ignition; Cooling; Lubrication; Transmission (clutch, gears, differential, final drive).
28.2.4 Tractor service and maintenance
28.2.5 Tractor drawn implements, their uses and maintenance: Attachment methods (one point hitch – draw bar, three point hitch — hydraulic and power take off- P. T. 0); Implements (trailer, disc plough, mould board plough, harrows – disc [plain, notched], spike toothed, spring tined, sub-soilers, ridgers); Rotary tillers; Mowers (Gyro, reciprocating, planters and seeders); Cultivators/weeders; Sprayers; Harvesting machines (grain, root crops, forage); Shellers.
28.2.6 Animal drawn implements, uses and maintenance: ploughs; carts; ridgers.

29.0.0 AGRICULTURAL ECONOMICS I (BASIC CONCEPTS AND FARM RECORDS)

29.1.0 Specific Objectives

By the end of the topic, the learner should be able to:
(a) define economics and agricultural economics;
(b) explain basic concepts of economics;
(c) describe the importance of agricultural economics;
(d) explain the importance of farm records;
(e) describe the different types of farm records;
(0 keep farm records.

29.2.0 Content

29.2.1 Definition: Economics and Agricultural Economics.
29.2.2 Basic concepts of economics: Scarcity; Preferences and choice; Opportunity cost.
292.3 Uses of farm records
29.2.4 Types of farm records: Breeding; Feeding; Production; Health; Field operations; Inventory; Labour; Marketing.

30.0.0 AGRICULTURAL ECONOMICS II (LAND TENURE AND LAND REFORM)

30.1.0 Specific Objectives

By the end of the topic, the learner should be able to:
(a) define the term tenure;
(b) describe tenure systems;
(c) describe land reforms

30.2.0 Content

30.2.1 Land tenure: Definition; Tenure systems – (I) individual (types, advantages and disadvantages) and (ii) Collective (description, advantages and disadvantages).
30.2.2 Land reforms: definition; types of reform and reasons for each (fragmentation, consolidation, adjudication, registration (emphasize the importance of a title deed); Settlement and resettlement.
31.0.0 AGRICULTURAL ECONOMICS III (PRODUCTION ECONOMICS)

31.1.0 Specific Objectives

By the end of the topic, the learner should be able to:
(a) explain various parameters of national development;
(b) relate national development to agricultural production;
(c) state the factors of production and explain how each affects production;
(d) describe how the law of diminishing returns relates to agricultural production;
(e) describe agricultural planning and budgeting in a farming business;
(0 state sources of agricultural support services;
(g) describe risks and uncertainties in farming;
(h) explain ways of adjusting to risks and uncertainties.

31.2.0 Content

31 .2.1 National income: Household-firm relationship; Gross Domestic Product (GDP); Gross National Product (GNP); Per Capita Income; Contribution of agriculture to national development.
31.2.2 Factors of production: Land (definition and methods of acquisition); Labour (definition, types, measures of labour, ways of increasing labour efficiency; Capital (definition, types and sources); Management (definition, role of a farm manager)
31.2.3 Production function: Increasing returns; Constant returns; Decreasing returns
3 1.2.4 Economic laws and principle: The law of diminishing returns; The law of substitution; The law of equimarginal returns; Principle of profit maximization.
31.2.5 Farm planning: Meaning; Factors to consider; Steps
31.2.6 Farm budgeting: Definition; Importance; Types (partial and complete)
3 1.2.7 Agricultural services available to the farmer
3 1.2.8 Risks and uncertainties in farming: Meaning; Common risks and uncertainties; Ways of adjusting.

32.0.0 AGRICULTURAL ECONOMICS IV (FARM ACCOUNTS)

32.1.0 Specific Objectives

By the end of the topic, the learner should be able to:
(a) state the importance of farm accounts;
(b) distinguish and describe the various financial documents and their uses;
(c) identify various books of accounts and their uses;
(d) prepare and analyse financial statements.

32.2.0 Content

32.2.1 Financial documents and books of accounts: Financial documents (Invoices,
Statements, Receipts, Delivery notes, Purchase orders); Books of Accounts
(Ledger, Journal, Inventory, Cash book); Financial statements; Cash analysis;
Balance sheet; Profit and loss account.

33.0.0 AGRICULTURAL ECONOMICS V (AGRICULTURAL MARKETING AND ORGANIZATIONS)

33.1.0 Specific Objectives

By the end of the topic, the learner should be able to:
(a) define market and marketing;
(b) describe the various types of markets;
(c) describe how the law of supply and demand affects the prices of agricultural products;
(d) state various marketing functions, agents and institutions;
(e) identi problems in marketing of agricultural products;
(f) list various agricultural organizations;
(g) describe the role of each of the agricultural organizations.
33.2.0 Content
33.2.1 Market and marketing
33.2.2 Types of markets
33.2.3 Demand, supply and price theory
33.2.4 Marketing functions
33.2.5 Problems of marketing agricultural products and possible solutions
33.2.6 Marketing boards, agents and institutions
33.2.7 Co-operatives: Formation; Functions
33.2.8 Associations and unions: Agricultural society of Kenya (ASK); Young Farmers Clubs (YFC); Kenya National Farmers Union (KNFU); Agricultural based Women groups.
APPENDIX RESOURCES

A TOOLS AND EQUIPMENT TO BE STUDIED
1. GARDEN TOOLS AND EQUIPMENT TO BE STUDIED

Panga Knap-sack sprayer
Axe Sprinkler
Mattock/pick axe Hose pipe
Jembe/hoe Garden shear
Fork jembe Pruning saw
Spade Pruning knife
Wheelbarrow Meter rule
Watering can Secateurs
Rake Garden fork
Tape measure Pruning-hook
Soil auger Levelling boards.

2. LIVESTOCK PRODUCTION TOOLS AND EQUIPMENT

Elastrator Stir-up pump
Burdizzo Milk churn
Syringes and needles Strainer/sieve
Thermometer Rope
Halter Milking stool
Hoof trimmer Weighing balance
Strip cup Hot iron
Trochar and canula Tooth clipper
Hard broom Drenching gun
Wool shears Dosing gun
Ear notcher Bolus gun
Bull ring and leading stick Dehorning wire
Bucket Chaff cutter

3. WORKSHOP TOOLS AND EQUIPMENT

Cross cut saw Jack plane
Tenon/back saw Scrapper
Coping saw Try square
Compass saw/key hole saw Wood clamp
Rip saw Sash clamp
Bow saw G-clamp
Hack saw Mallet
Wood chisel Soldering gun
Cold chisel Tin-snip
Mes and rasps Claw hammer
Divider Sledge hammer
Center punch Wire strainer
Spoke share Pliers
Screw drivers Brace and bits
Spanners Hand drills and bits
Pipe wrench Riveting machine
Pipe cutter Crow bar
Levelling rod Masons’ square
Spirit level Plumb bob
Mason’s trowel Metal float
Wood float Shovel
Meter rule

1. WEEDS TO BE STUDIED

COMMON NAME BOTANICAL NAME

1. Black Jack Bidens pilosa
2. Mexican marigold Tagetes minuta
3. Oxalis/sorrel Oxalis species
4. Double thorn Oxygonum sinuatum
5. Thorn apple Datura stramonium
6. Couch grass Digitaria scalarum
7. Nut grass Cyperusrotundus
8. Wandering Jew Commelina benghalensis
9. Sow thistle Sonchus oleraceus
10. Devil’s horsewhip Achyranthes aspera
11. Macdonald /gallant soldier Gallinsoga parvfrlora
12. Sodom apple Solanum incanum
13. Black nightshade Solarium nigrum
14. Chinese lantern Nicandra physalodes
15. Bracken fern Pteridium acquilinum
16. Love grass/Bristly foxtail Setaria verticillata
17. Cleavers Gallium spurium
18. Stinging nettle Utica massaica
19. Fat hen/Goosefoot Chenopodium species
20. Rape weed Brassica napus
21. Wild oats Avenafatua
22. Lantana/tick berry Lantana camara
23. Water hyacinth Eichhornia crassipes
24. Witchweed Striga hermonthica
25. Creeping indigo Indigofera spicata

1. CROP PESTS TO BE STUDIED

1. Armyworm
2. Cut worm
3. Locust
4. Moths
5. Fruitfly
6. Mealybug
7. Thrips
8. Beetles
9. Weevils — field and store
10. Birds — weaver, sudan dioch, Mouse bird
11. Rodents — Squirrels, Moles and Rats
12. Boll worms
13. Stainers
14. Nematodes
15. Leaf miners
16. Aphids
17. Stalk borers
18. Loopers
19. Scales.

1. CROP DISEASES TO BE STUDIED
2. maize streak
3. Smuts
4. Blasts
5. Leaf blight
6. Anthracnose
7. Rusts in cereals and leaf rust in coffee
8. Leaf spot
9. Blight-halow, Early and late
10. Panama disease
11. Cigar-end-rot
12. Mildew
13. Mosaic
14. Die-back
15. Greening
16. Tristeza
17. Wilts – Fusarium and Bacterial
18. Black arm
19. Damping off
20. Coffee Berry Disease
21. Rosette
22. Ratoon stunting disease
23. Armillaria root-rot.

  HEAT CAPACITY

1. Define specific latent heat of fusion of a substance        (1mk)

2. Distinguish between heat capacity and specific heat capacity of a substance.

3. Give the property of water which makes it suitable for use as a coolant in machines                                                                           (1mk)

4. Equal masses of water and paraffin are heated for same length of time. The final temperature of paraffin was found to be greater than the final temperature of water. Explain the observation.                 (2mk)

5. A student states that when two bodies at different temperatures are brought into contact the resulting rise of temperature in one will be equal to the fall in temperature in the other. Give two reasons why this statement is wrong
6. (i) Describe how you would attempt to measure the specific heat capacity

of aluminium by method of mixtures.                                        (3mk)

(ii)    State one source of experimental error in this method.         (1mk)

(iii)    Give one way you could take to reduce the magnitude of the error you have mentioned.                                                                (1mk)

7. Briefly describe an experiment to determine the specific heat capacity of a liquid substance using the electrical method.                         (6mk)

8. A liquid at 80°C in a cup was allowed to cool for 20 minutes. State two factors that determine the final temperature.         (2mk)

9. Equal masses of water and ice at 0⁰C are added separately into two identical beakers containing equal amount of water. State the reason why ice may cause a greater change of temperature.                         (1mk)

10. Figure below shows the temperature changes against quantity of heat supplied to one kilogram each of liquids A and B.

Which of the two liquids has a high specific heat capacity?  Give a reason.(2mk)

11. 500g of water at 20^oc is mixed with 200g of water at 55^oc. Find the final temperature of the mixture.

12. Calculate the heat evolved when 100g of copper are cooled from 90⁰c to 10⁰ (Specific Heat Capacity of Copper = 390J/Kgk).

13. An iron block of mass 20g is left in water boiling at 95⁰C for some minutes then transferred quickly to a well-lagged copper can of mass 40g containing 60g of water at 20⁰C. The mixture is well stirred and the final temperature T is noted. Given that the specific heat capacity of copper = 400JKg^-1K^-1, Iron = 460JK^g-1K-1 and water = 4200JK^g-1K-1, find the value of T.

14. 100g of boiling water are poured into a metal vessel weighing 800g at a temperature of 20⁰C if the final temperature is 50⁰ What is the specific heat capacity of the metal? (Specific Heat capacity of water 4.2 x 10³J/kgk)

15. You are provided with two beakers. The first beaker contains hot water at 70⁰  The second beaker contains cold water at 20⁰C.  The mass of hot water is thrice that of cold water.  The contents of both beakers are mixed.  What is the temperature of the mixture?
16. Water at 24⁰C fall through a height of 72m to the bottom of a dam. Calculate the temperature of the water at the bottom of the dam. (Take specific heat capacity of water as 4200JKg^-1K^-1)

17. A lead weight is dropped from a helicopter hovering at 100m above the ground. Assuming that all the energy is converted into heat energy, determine the rise in temperature of lead. Take specific heat capacity of lead to be 130J/kgk.                                  (3mks)

18. Water flows from a high dam down a vertical cliff 100m high. The temperature of the water reaching the ground is 23⁰C Determine the temperature of water in the dam. Assume evaporation and sound produced due to the flow are negligible and the specific heat capacity of water is 4200J kg ^-1 K^-1 (3mk)           

19. An energy saving stove when burning steadily has an efficiency of 60%. The stove melts 03kg of ice at 0⁰c in 180 seconds.

Calculate; –

1. The power rating of the stove.
2. ii) The heat energy wasted by the stove.

20. Water at 20⁰c spills over a waterfall of height 10m. Calculate the rise in temperature of water at the bottom of the waterfall if 80% of potential energy at the top of waterfall is converted into heat at the bottom of the waterfall. Take specific heat capacity of water 4200j/Kg^-1 K^-1) (4mk)

21. In a domestic oil-fired boiler, 5kg of water flows through the boiler every second. The water enters the boiler at a temperature of 30⁰C and leaves at a temperature of 70⁰C, re-entering the boilers after flowing around the radiators at 30⁰C.  3.0x 10⁷J of heat is given to the water by each kilogram of oil burnt.  The specific heat capacity of water is 4200Jkg ^-1K^-1

• Use the information above to calculate the energy absorbed by the water every second as it passes through the boiler
• Use the same information above to calculate the mass of oil which would need to be burnt in order to provide this energy.

ELECTRICAL MTD

1. A heating element rated 2.5 KW is used to raise the temperature of 3.0 kg of water through 50⁰ calculate the time required to effect this. ( Specific heat capacity of water is 4200J/kgK).                                  (3mk)

2. An electric heater rated 300 W heats some liquid of heat capacity 1680 J/K for 2 minutes. Find the rise in temperature.                (3mk)

3. An immersion heater rated 1500W is used to heat a block of ice of mass 500g initially at -10°C for 2.5 minutes. If the final temperature is 20°C determine the specific latent heat of fusion of the ice (Take specific heat capacity of water as 4200J/KgK, specific heat capacity of ice = 2100J/KgK) (4mk)

4. An immersion heater takes a current of 10A when connected to 240V supply. If it is used to heat 5Kg of water at 20⁰C, find the temperature of water after 4 minutes of heating.                                  (3 mks)

5. A hot-water tank for a house contains 150kg of water at 15⁰ the tank itself has a heat capacity of 6000 JK^-1. An immersion heater is used to heat the water to 50⁰c. the tank is well insulated and the power of the heater is 2500W (specific heat capacity of water =4200 JKg^-1K^-1)

• Find the amount of heat transferred to the water (2mk)
• find how much heat is absorbed by the tank              (2mk)
• Determine the time it will take the heater to raise temperature to 50⁰

(3mk)

6. A metal cylinder of mass 500g is heated electrically. If the voltmeter reads 15V, the ammeter 3.0A and the temperature of the block varies from 20⁰ C to 85⁰ C in 10 minutes. Calculate the specific heat capacity of the metal cylinder.(3mk)

7. An-immersion heater rated 150W is placed in a liquid of mass 5 kg. When the heater is switched on for 25 minutes, the temperature of the liquid rises from 20⁰C – 270⁰C.  Determine the specific heat capacity of the liquid.  (Assume no heat losses)

8. An immersion heater which takes a current of 3A from 240V mains raised the temperature of 10kg of water 30⁰c to 50⁰ How long did it take?

9. An immersion heater rated 90W is placed in a liquid of mass 2kg. When the heater is switched on for 15 minutes, the temperature of the liquid rises from 20⁰C to 30⁰C. Determine the specific heat of the liquid.

10. Figure below shows a set up in an experiment to determine specific heat capacity of water.

The data below was obtained was obtained from the experiment

• Voltage V across the heater = 12V
• Current I in the circuit   = 1.4A
• Time (t) heating                = 600s
• Mass m of water = 0.4kg
• Change in temperature DT = 6ºc

1. Define specific heat capacity
2. State two improvements that would be made in the set up to obtain accurate

• Use the above results to determine the specific heat capacity of water.

GRAPH

1. The figure below shows a graph of the variation of temperature with time for a pure substance heated at a constant rate

Assuming that heat transfer to the surrounds is negligible, state the changes observed on the substance in region.

1. a) BC                                                                                                                                                           (1mk)
2. b) DE                                                                                                                                                           (1mk)
3. The figure below shows a graph of temperature against time for a given substance (water)

State what happens in the section labelled

• BC                     (1mk
• CD            (1mk)
• DE            (1mk)

3. A 250 g sample of a solid was heated steadily in a lagged colorimeter of negligible mass. The observations were represented in a graph as shown below.

(i)     Explain the shape of the graph       (3mks)

(ii)     The solid requires 12.5J of energy to change its state. Calculate its specific latent heat of fusion.                                                                       (2mks)

4. The cooling curve below is for a pure substance

(a) What is the melting point of the substance                   ( 1 marks )

(b) What point of the curve is the substance?

(i)     solid                                                                        (1mk)

(ii)     Liquid                                                                             (1mk)

(iii)    Solid and liquid                                                               (1mk)

5. Figure below shows the variation of temperature ‘q’ with time t, when an immersion heater is used to heat a certain liquid. Study the figure and answer questions (i) and (ii).

(i)         State the reason for the shape of the graph in the section labelled BC.                                                    (1mk)

(ii) Sketch on the same axes the graph for another liquid of the same mass but higher specific heat capacity when heated from the same temperature.(1mk)

6. In an experiment to determine the specific heat capacity of liquid, a student used 0kg of each of the liquids, water, glycerin and paraffin. Each of the liquids was supplied with 21600J of heat energy under the same conditions. The table below shows temperature rise for the liquids.

(i) Suggest a reason for the difference in the difference in the rise of

temperature.                                                                      (1mk)

(ii) Calculate the specific heat capacity of paraffin                       (3mk)

7. Njoroge wanted to determine the heat energy, W, required to change one kilogram of water into vapour at a constant temperature. He set up the arrangement as shown below;

He took the reading M, of the balance at a given time interval. He obtained the following data

(a)    Plot a graph of mass against time                             (5mk)

• Determine the gradient of the graph                    (3mk)
• What does the gradient represent? (1mk)
• A steady current of 4A and potential difference of 12V were recorded during the experiment. Determine the value of W. (4mks)

11. A 125W heater and a thermometer were immersed in 0.6kg of oil in a vessel of negligible heat capacity. The following observations were noted.

1. i) Plot a suitable graph and use it to find: (4mks)
2. ii) the average rise in temperature per minute.          (2mks)

iii)  the temperature at which the heating started.              (1mk)

1. iv) Hence, calculate the specific heat capacity of the oil.(2mks)

8. The table below shows values of temperature against time for a pure substance subjected to heat

1. a) Draw a graph of temperature against time showing the effect of heating the solid substance          (5mks)
2. b) From the graph, state the melting point and boiling point of the substance.

(2mk)

1. c) If the loss in mass of the substance during vaporization is 70g and the heat supplied at a rate of 720J/min, calculate the specific latent heat of vaporization of the liquid substance                   (3mk)

9. A 4g mass is receiving heat at the rate 100kJ per minutes and its temperature at various times recorded as follows

Plot a graph of temperature against time on the grid provided                  (4mks)

• Use your graph to find

(i)    The specific heat capacity of the substance in its liquid state        (3mk)

(ii)    Its boiling point                                                               (1mk)

(iii)   Its melting point                                                                  (1mk)

(iv)    The specific latent heat of fusion of the substances       (3mk

10. In an experiment to determine the specific latent heat of vaporization of a liquid using an electrical method, the amount of heat, Q, required to vaporize a given mass, m, of a liquid were recorded as shown.

(i) On the grid provided plot a graph of Q (y-axis) against m.          (5mks)

(ii) From the graph, determine the specific latent heat of vaporization of the

liquid.                                                                    (3mks)

(iii) Suggest a reason why the graph does not pass through the origin.                                                                                                               (1mk)

(iv) Write a possible equation of this graph.                                (1mk)

LATENT HEAT OF FUSION AND VAPORIZATION

11. Define latent heat of fusion of a substance        (1mk

12. Define specific latent heat of fusion of a substance        (1mk)

13. Define specific latent heat of vaporization of a substance        (1mk)

14. State two physical quantities that remain constant while pure ice is being converted to water.

15. State two factors that affect the melting point of ice. (2mk)

16. Explain why a burn from the steam of boiling water is more severe than that of water itself?

17. A burn from steam is more severe than one from water boiling at the same temperature .Give reasons.

18. The setup shown below was used to determine the specific latent heat of vapourisation of water.

Describe how you would use the apparatus to determine the specific latent heat of vapourisation of water stating any assumption made and the measurements one would take.                                    (6mk

19. You are provided with the following apparatus:A filter funnel, a thermometer, a stop watch, ice at 0°C, an immersion heater rated P watts, a beaker, a stand, boss and clamp and a weighing machine. Describe an experiment to determine the specific latent heat of fusion of ice. Clearly state the measurements to be made. (4mk)

20. In an experiment to determine the power of an electric heater, melting ice was placed in a container with an outlet and the heater placed in the ice as shown below. The heater was connected to a power supply and switched on for some time. The melted ice was collected.

1. a) Other than the current and voltage, state the measurement that would be taken to determine the quantity of heat absorbed by the melted ice in unit time. (2mk)
2. b) If the latent heat of fusion of ice is L, show how measurements in (i) above would be used in determining the power P, of the heater, (2mk)
3. c) It is found that the power determined in this experiment is lower than the manufacturer’s value indicated on the heater.       (1mk)

CALCULATIONS

1. 50g of steam at 100^oC was passed into cold water at 20^oC. The temperature on the water rose to 60^oC.  Determine the mass of cold water used (specific heat capacity of water = 4200J/KgK and specific latent heat of vapourisation of water = 2.26 x 10⁶ JKg-1)              (4mk)

2. Dry steam is passed into a well-lagged copper can of mass 250g containing 400g of water and 50g of ice at 0⁰. The mixture is well stirred and the steam supply cut off when the temperature of the can and the contents reach 20⁰C.

• Draw an experiment set-up that can be used to find the mass of steam

condensed                                                                       (4mk)

 (b) Neglecting heat losses, find the mass of steam condensed     (4mk)

3. In an experiment to determine the specific latent heat of vaporization of water steam at 100⁰Cwas passed into water contained in a well lagged Calorimeter, the following measurements were made.

Mass of calorimeter                                              =60g

Initial mass of water                                   =80g

Final mass of calorimeter + condensed stem.        =143g.

Initial temperature of mixture                              =17⁰C

Final temperature of mixture                               =32⁰C

Specific heat capacity of copper                   =390J/KgK

1. Determine the mass of condensed steam.     1mk
2. Determine the heat gained by calorimeter and water. 3mk

• Determine the latent heat of vaporization of steam. 3mk

4. In an experiment to determine the specific latent heat of vaporization of water, steam at 100⁰c was passed into water contained in a well-lagged copper calorimeter. The following measurements were made:

• • • • Mass of calorimeter      = 50g
      • Initial mass of water     = 70g
      • Final mass of calorimeter + water + condensed steam = 123g
      • Initial temperature of water = 5^oc
      • Final temperature of mixture = 30⁰C

(Specific heat capacity of water = 4200 J kg ^–1K and specific heat capacity for copper = 390 J kg ^-1 K^-1)

Determine the

1. a) Mass of condensed steam
2. b) Heat gained by the calorimeter and water
3. c) Given that L is the specific latent heat of evaporation of steam

(i) Write an expression for the heat given out by steam

                 (ii)   Determine the value of L.

5. Steam of mass 3.0g at 100⁰c is passes into water of mass 400g at 10⁰ The final temperature of the mixture is T. The container absorbs negligible heat. (Specific latent heat of vaporization of steam= 2260 kJ/kg, specific heat capacity of water= 4200Jk^-1)
6. i) Derive an expression for the heat lost by the steam as it condenses to water at temperature T.          (2mk)
7. ii) Derive an expression for the heat gained by the water. (2mk)

    iii)        Determine the value of T.                                   (2mk)

6. What mass of steam initially at 130⁰C is needed to warm 200g of water in a glass container of mass 100g from 20⁰C to 50⁰?

Specific heat capacity of steam                = 200JKg^-1K^-1

                        Specific heat capacity of water                = 4200 JKg^-1K^-1

Specific latent heat of vaporization of water = 2.26 x 10⁶JKg^-1

Specific heat capacity of glass                 = 840JK^-1K^-1    4mks

7. A can together with stirrer of total head capacity 60J/k contains 200g of water at 10⁰ dry steam at100⁰c is passed in while the water is stirred until the whole reaches a temperature of 30⁰c Calculate the mass of steam condensed.

8. 02kg of ice and 0.01kg of water 0⁰c are in a container. Steam at 100⁰c is passed in until all the ice is just melted.  How much water is now in the container?

9. 200 g of ice at 0°C is added to 400g water in a well lagged calorimeter of mass The initial temperature of the water was 40°C. If the final temperature of the mixture is X°C, (Specific latent of fusion of ice L = 3.36 x 10⁵ Jkg^-1, specific heat capacity of water, C = 4200Jkg^-1K^-1, specific heat capacity of copper = 400 Jkg^-1K^-1.)

(i)     Derive an expression for the amount of heat gained by ice to melt it and raise its temperature to X°C                            (2mk)

(ii)     Derive an expression for the amount of heat lost by the calorimeter and its content when their temperature falls to X°C.          (2mks)

(iii)    Determine the value of X.                                        (3mks)

10. In an experiment to determine the specific latent heat of vaporization L of water, steam at 100°C was passed into water contained in a well legged copper calorimeter. The following measurements were made.

Mass of calorimeter = 80g

Initial mass of water = 70g

Initial temperature of water = 5°C

Final mass of calorimeter + water +condensed steam =156g

Final temperature of mixture = 30°C

Specific heat capacity of water = 4200JKg^-1K^-1and specific heat capacity for copper =     390J/Kg^-1K^-1)

(a) Determine the:

(i) Mass of condensed steam                                    (2mks)

(ii) Heat gained by the calorimeter and water                     (1mk)

(b)    Given that L. is the specific latent heat of vaporization of steam

(I) Write an expression for the heat given out by steam.             (1mk)

(II) Determine the value of L                           (3mks)

11. In an experiment to determine specific latent heat of water, steam at 100⁰C was passed into the water container, the following measurements were made.
    • Initial temperature of water = 15⁰C
    • Mass of Calorimeter = 60g
    • Initial mass of water = 80g
    • Final mass of water + calorimeter + condensed steam = 160g
    • Final temperature of mixture = 40⁰C
    • Specific heat capacity of water = 4200 J/Kg
    • Specific heat capacity of copper = 390J/Kgk

         (a) Calculate

         (i)    Mass of condensed steam.                                                (1mk)

                 (ii)   Heat gained by calorimeter and water.                              (5mk)

         (b) Given that L_v is the specific latent heat of vaporization of steam.

1. i)      Write an expression for the heat given out by steam.         (1mk)
2.          ii)     Determine the value of L_v.                                      (3mk)

12. In an experiment to determine the specific latent heat of vaporization of water. Steam at 100⁰C was passed into water container in a well lagged calorimeter. The following results were obtained Mass of calorimeter =50g

• Initial temperature of water =20⁰C
• Initial mass of water =60g
• Final mass of calorimeter +water +condensed steam =115g
• Final temperature of mixture =30⁰C
• Specific heat capacity of water =4200J/kgk
• Specific heat capacity of copper =400J/kgk

(a) Draw a possible set up that can be used in the above experiment   (3mks

(b)    Determine.

(i)The mass of condensed steam                                       (1mk)

(ii)The heat gained by the calorimeter and water                  (3mks)

(c)      Given that L is the specific latent heat of vaporization of steam,

(i)Write down an expression for the heat given out by steam   (1mk)

(ii)Determine the value of L                                              (2mks)

13. Water of mass 200g at a temperature of 60^oC is put in a well lagged copper calorimeter of mass 80g. A piece of ice at 0^oC and mass 20g is placed in the calorimeter and the mixture stirred gently until all the ice melts. The final temperature of the mixture is then measured

(Latent heat of fusion of ice = 33400Jkg^-1, specific heat capacity of water = 4200Jkg^-1K^-1) Determine:

(i)    The heat absorbed by the melting ice at 0^oC     (2mks)

(ii)   The heat absorbed by the melted ice (water) to rise to temperature T                                                (2mks)

 (iii) The heat lost by the warm water and the calorimeter (Specific heat capacity of the calorimeter = 900Jkg^‑1K^-1)              (2mks)

(iv)   The final temperature T of the mixture             (3mks)

14. A copper block of mass 800g is suspended in a freezing mixture -60⁰C for some time and then transferred to a large volume of water at 0⁰C. A layer of ice is formed on the block. Take specific heat capacity of copper =360JKg^-1K^-1, latent heat of fusion 336,000JKg^-1
15. i) Give a reason for the formation of ice                           (1mk)
16. ii) State the temperature of the copper block after this change is complete

(2mk)

    iii)    Determine the mass of ice formed                              (3mk)

15. In a cooling system 100g of steam at 100⁰C was passed into cold water at 40⁰C. The temperature rose to 70⁰C (specific heat capacity of water = 4200J kg^-1K^-1, latent heat of vaporization of steam = 2.2 x 10⁶Jkg^-1)

Calculate

1. i) Heat lost by steam                                                   (2mk)
2. ii) Heat lost by condensed steam                                  (3mk)

iii)     The mass of cold water used                                     (3mk)

16. Water of mass 400g at a temperature of 60^oC is put in a well lagged copper calorimeter of mass 160g. A piece of ice at 0^oC and mass 40g is placed in the calorimeter and the mixture stirred gently until all the ice melts. The final temperature, T, of the mixture is then measured. Determine;

(i)     The heat absorbed by the melting ice at 0^oC             (2mk)

(ii)    The heat absorbed by the melted ice (water) to rise the temperature T (Answer may be given in terms of T)  (2mk)

(iii)    The heat lost by the warm water and the calorimeter (The answer may be given in terms of T)                          (2mk)

(iv)   The final temperature T of the mixture (Specific latent heat of fusion of ice = 334000J/kg, specific heat capacity of water = 4200J/kgK, specific heat capacity of copper = 900J/kgK)                 (4mk)

17. The melting point of a certain bullet is 300⁰c. If the initial temperature of the bullet is 20⁰c , determine the least speed at which the bullet would be moving so that it just melt when suddenly stopped. Specific heat capacity of bullet = 840 J/kgK; specific heat of fusion of material making bullet = 6.3 x 10⁴ J/kgK                                                                          (3mk)

18. 32g of dry ice was added to 200g of water at 25⁰C in a beaker of negligible heat capacity. When all ice had melted the temperature of water was found to be 10⁰C. (Take specific heat capacity of water to be 4200JKg^-1K^-1)

(i)     Calculate the heat lost by water                                     (2mks)

(ii)     Write an expression for the heat gained by ice to melt and for temperature to rise to 10⁰C.                                                              (2mks)

(iii)    Calculate the specific latent heat of fusion of ice.                       (2mks)

19. A jet of dry steam at 100⁰C is sprayed on to the surface of 100g of dried ice at 0⁰C contained in a well-lagged calorimeter of negligible heat capacity, until all the ice has melted and the temperature begin to rise. The mass in the calorimeter when the temperature reaches 40⁰C is found to be 120g.Assuming that the specific latent heat of fusion of ice is 336000JKg^-1, specific heat capacity of water is 4200JKg^-1K^-1, Determine the specific latent heat vaporization of water.                                           (4mks)
20. 5 grammes of water at 20⁰C is heated until it boils at 95⁰ On further heating the temperature of Water does not change until it has all evaporated.

(i) State what happens to the energy supplied to the water after attaining a temperature of 95⁰C.                                                                 (1 mk)

1. ii) Calculate the amount of heat required to convert all the 5g of water to steam.

Latent heat of vaporization of water = 2260000 J/Kg)              (6mk)

21. What mass of steam initially at 130⁰C will raise the temperature of 0 Kg of water contained in a 1.0 Kg glass container, from 20⁰C to 50⁰C? (4mks)
    • Specific heat capacity of steam =      200J Kg^-1 K^-1
    • Specific heat capacity of water =      4200 J Kg^-1 K^-1
    • Specific latent heat steam =      26 x 10⁶ J Kg^-1
    • Specific heat capacity of glass =      840 J Kg^-1 K^-1

ELECTRICAL

1. An immersion heater rated 1000W is used to heat a block of ice of mass 500g initially at -10°C until the all the water evaporates at 95°C. Assuming that all the heat supplied is used to heat the ice, calculate the time in minutes for the whole process to take place. (Take specific heat capacity of water as 4200J/KgK, specific heat capacity of ice = 2100J/KgK specific latent heat of fusion = 3.35 x 10⁵ J/Kg and specific latent heat of vapourization = 2.26 x 10⁵J/Kg) (5mk)

2. An electric kettle rated at 2.5kW contains 1.6kg of water. It is left switched on after boiling.

    (i)         How much heat energy will be used in turning all the water to steam?(2mk)

    (ii) Determine how long will it take for the 2.5kw kettle to boil dry (2mk)

3. An electric heater rated 5 kW is used to melt 1.5 kg of ice at 0°C. Calculate the specific latent heat of fusion of ice, if it takes 5 minutes for the heater to melt all the ice. (3mk)

4. A 180W heater is immersed in a copper calorimeter of mass 100g containing 200g of alcohol. When the heater is switched on after 36sec the temperature of the calorimeter and its contents raises by 12⁰ what is the specific heat capacity of alcohol. (SHC of Cu = 400J kg^-1 K^-1) (4mks)

5. An electric heater rated 6000W is used to heat 1kg of ice initially at -10⁰c until all the mass turns to steam. Given that

• • • Latent heat of fusion = 334kJ kg ^-1
    • Specific heat capacity of ice = 2,260J kg ^-1 K ^-1
    • Specific heat capacity of water  = 4, 200J kg^-1 K^-1
    • Latent heat of vaporization = 2, 260KJ kg ^-1 K ^-1

Calculate the minimum time required for this activity.

EVAPORATION AND BOILING

1. Distinguish between evaporation and boiling (2 mks)

2. State the two factors that affect the boiling point of water and in each case, explain how the boiling is affected. (4 mk)

3. State two factors that would raise the boiling point of water to above 100⁰c

4. When two pieces of ice blocks are squeezed together once they form one block. Explain

5. Figure below shows a block of ice with two heavy weights hanging such that the copper wire / string connecting them passes over the block of ice.

• It is observed that the wire gradually cuts its way through the ice block, but leaves it as one piece. Explain

(ii)     What change would be observed if the  copper wire used in the experiment was      replaced by a cotton thread.  Explain your answer.

6. A student put some small pieces of ice in a beaker and sprinkled salt on the ice. He stirred until the ice melted and took the temperature of the content in the beaker- as shown.

(i)     State the observation made.                                      (1mk)

(ii)     Explain the observation.                                  (1mk)

7. The figure below shows two identical containers A and B containing hot water and ice block.

State with reason which water cools faster assuming that the wire gauge absorbs negligible heat                                                                                      (2mk)

8. Figure below shows two identical beakers A and B. Beaker A contains water at 0°C while B contains water and pieces of ice at 0°C. Both contents have the same mass.

Two identical metal blocks are removed from the same hot furnace and dropped into each of the beakers. Identify which of the two beakers would experience more evaporation and give a reason for your answer.(2mk)

9. Figure below shows two sufurias with equal amount of water R heated at the same rate.

1. i) State which water boiled first.          (1mk)
2. ii) Explain your answer                  (1mk)

10. The diagram below shows two cups of tea containing equal volumes of hot tea. The cups have different diameters.

State giving reasons, the cup whose tea will cool faster than the other.   (2mk)

11. Ether is put into a beaker which is placed on a thin film of water. A student blows the ether through a pipe continuously. State and explain the observation made after some time         (2mk)

12. The rate of evaporation can be increased in a number of ways. State two ways in which this could be achieved                                        (2mk)

13. Some water is stored in a bag made of a porous material e.g. canvas which is hung where it is exposed to a draught of air (wind). Explain why the temperature of the water is lower than that of the air. (2 mk)

14. Explain why food cooks faster in a pressure cooker than in an open sufurias

15. Explain why the cooling unit (freezer) inside a refrigerator is placed near the top but an elastic immersion heater in water tank should be near the bottom.(2mk)

16. A thin layer of water underneath a beaker containing ether freezes when air is blown through ether. Explain why the water freezes. (1mk)

17. Hot milk in a bottle cools faster when wrapped in a wet cloth than when the bottle is immersed in cold water in a bucket. Explain why.          (3 mk)

18. State the property of Freon that makes it useful as a refrigerant liquid (1mk)

19. Figure shows the features of a domestic refrigerator. A volatile liquid circulates the capillary tubes under the action of the compression pump.

• State the reason for using a volatile liquid. (1mk)

(ii)        Explain how the volatile liquid is made to vaporize in the cooling compartment and to condense in the cooling fins. (2mk)

(iii)       Explain how cooling takes place in the refrigerator. (3mk)

(iv)       What is the purpose of the double wall?           (1mk)

20. Figure below shows a domestic electric refrigerator

(i)     Label the parts

X____________                                            (1mk)

         Y____________                                            (1mk)

(ii)     What property is considered when selecting the liquid used as refrigerant?                                           (1mk)

(iii)    If you stand near the back of a refrigerator you feel warm. Explain.                                                                                            (1mk)

(iv)    Explain how the refrigerator works                           (4mks)

SCHEME

1. Give the property of water which makes it suitable for use as a coolant in machines                                                                                           (1mk)

Water has a high heat capacity hence can absorb a lot of heat Pj

1. A burn from steam is more severe than one from water boiling at the same temperature .Give reasons.
   1. Steam already contains latent heat of ; P evaporation which water doesn’t have ;P

RADIOACTIVITY

INTRODUCTION

• In 1896 Henri Becquerel accidently discovered that Uranium salt crystals emitted invisible radiation that darkened a photographic plate even when covered to exclude light.
• Madame Curie & her husband Pierre discovered Polonium & Radium.
• Marie Curie described these elements as being radioactive and concluded that the radiations originate from the nucleus. They called this phenomenon

Radioactivity or radioactive decay is the spontaneous disintegration of unstable nuclides to form stable ones with the emission of radiation. Unstable nuclides continue to disintegrate until a stable atom is formed.

ATOMIC STRUCTURE

The nucleus of an atom has a specific number of protons and neutrons. The number of protons in the nucleus is called the atomic or proton number while the sum of the number of protons and neutrons is called the mass or nucleon number.

An atom X of mass number A and atomic number Z can be represented as . If the number of neutrons in the nucleus is N, then:

A= Z+N.

Thus, hydrogen can be represented by , helium by and neon by . Some atoms have the same number of protons in the nucleus yet different mass numbers. Such atoms are referred to as isotopes. Examples of isotopes include carbon- 12 and carbon- 14. Isobars – are nuclides with the same mass number A but different atomic number Z – Ra, Ac. Th.

The energy holding the protons and neutrons together in the nucleus is called the binding or nuclear energy.

The masses of atoms are conveniently given in terms of atomic mass units (u) where (u) is 1/12th the mass of one atom of carbon-12 and has a value of 1.660 × 10-27 kg. Hence the mass of one proton is equal to 1.67 × 10-27 and is equal to 1u.

NUCLEAR STABILITY

When the ratio of the number of protons to the number of neutrons in a nucleus is about 1:1, the nuclide is said to be stable, otherwise it is an unstable. For unstable nucleus, it has to undergo disintegration in an attempt to achieve stability. Below is a stability curve;

From the graph, it is observed that the unstable nuclides are outside the stability line. Those nuclides above the stability line have too many neutrons; hence decay in such a way that the proton number increases. Those below the stability line have too many protons and therefore decay in such a way that their proton number decreases.

TYPES OF RADIACTIONS

In the process of disintergration of radioactive elements, there are three radiations which may be emitted namely;

• Alpha (α) radiations
• Beta (β) radiations
• Gamma (γ) radiations.

Radiations emitted by radioactive elements are identified according to the properties they exhibit. Their behavior can be observed when they are passed through a magnetic or an electric fields

Similarly, their behavior can be observed when they are passed through a field as shown below:

1. ALPHA (α) RADIATIONS:

• Are positively charged.
• Are massive or heavy and thus have shorter range in air. They are slightly deflected by strong magnetic or electric field due to their higher mass.
• Cause the highest ionization effect on the particles on their paths compared to beta and gamma radiations, thereby losing most of their energy.
• Have the least penetrating ability or power compared to the other two radiations. They can be stooped by a thick sheet of paper.

1. BETA RADIATIONS:

• Are negatively charged.
• Are lighter compared to alpha radiations. Hence they are greatly deflected by strong magnetic or electric field.
• Have longer range in air.
• Cause less ionization compared to alpha radiations. Hence they have a higher penetrating ability or power. They can penetrate a thick sheet of paper but can be stopped by a thin aluminium foil.

1. GAMMA RADIATIONS:

• Are massless and do not have charge. Hence they are not deflected by both magnetic and electric fields.
• Are electromagnetic waves.
• Cause very little ionization. Hence most of their energy is intact. They have the highest penetrating ability or power of all the three radiations. They can penetrate thick paper and aluminium but is stopped by thick lead.

COMPARISONS OF THE THREE RADIATIONS

• Range in air
• α-particles – are the least penetrating of the three radiations.

They have a few cm in air about 5 cm.

• β-particles – are more penetrating than alpha particles.

Several metres in air – 5m

• g-rays – are the most penetrating of the three. Hardly affected by air. Intensity reduces as they spread.
• Absorption
• α-particles – are stopped by very thin aluminium, paper or skin.
• β-particles – can pass through 1 mm of aluminium: -stopped by a few mm of aluminium or Perspex.
• g-rays – can pass through metal and even several mm of lead but stopped by 5 cm of lead.

N/B 1 cm thickness of lead is referred to as the half-thickness for the lead since it lowers the intensity of the radiation to half the original volume. Gamma rays are similar to the x-rays, but they have a generally shorter wavelength. The main difference between X-rays and gamma rays is that gamma rays originate from energy changes in the nucleus of atoms while X-rays originate from energy changes associated with electron structure of atoms.

• Effect of electric field
• α-particles – Small deflection.

Attracted towards the negative plate, indication a (+ve) charge.

• β-particles – Strongly deflected.