KUULCHAT
SCIENCE MOCK

OBJECTIVE TEST

1.

The conversion of agricultural produce from its original form to other desirable forms is termed

A.

preservation.

B.

processing.

C.

recycling.

D.

storage.

Answer: B

2.

In a third-class lever the

A.

pivot is between the load and effort

B.

pivot is absent

C.

load is between the effort and pivot

D.

effort is between the load and pivot

Answer: D

3.

Benedict's solution was added to a mixture in a test tube and it turned brick red when heated. The mixture is likely to contain

A.

glucose.

B.

oil.

C.

protein.

D.

vitamin

Answer: A

Benedict Solution Test

Benedict’s test is a chemical test that can be used to check for the presence of reducing sugars such as glucose in a given analyte.

When there is a presence of a reducing sugar, the mixture turns brick red.

4.

When the testa of a soaked bean is removed, the seed is seen to be made up of

A.

cotyledons.

B.

embryos.

C.

micropyles.

D.

radicles.

Answer: A

5.

An example of a mixture is

A.

sodium sulphate.

B.

hydrogen chloride.

C.

ammonia.

D.

salt solution

Answer: D

Only salt solution is a mixture (mixture of salt and water). The rest are all compounds.

6.

Plantain is propagated vegetatively by

A.

corms.

B.

stem cuttings.

C.

suckers.

D.

rhizomes.

E.
tubers.

Answer: C

7.

Which of the following crops should be planted after cassava in crop rotation?

A.

Cocoyam

B.

Cowpea

C.

Onion

D.

Yam

Answer: B

In crop rotation, shallow-rooted crops follow deep-rooted crops and the vice versa.

Cassava is a deep-rooted crop and hence should be followed by cowpea which is a shallow-rooted crop.

8.

The purpose of vaccination is to

A.

replace poisoned tissues

B.

kill disease-producing organisms in the body

C.

increase the activity of white blood cells

D.

induce the production of anti bodies

E.
cure the disease

Answer: D

9.

The air pressure at great heights can be measured with

A.

A thermometer

B.

An anemometer

C.

A barometer

D.

A hydrometer

E.
A hygrometer

Answer: C

10.

The gas produced when glucose is oxidized during aerobic respiration is

A.

Hydrogen

B.

Nitrogen

C.

Oxygen

D.

Carbon dioxide

Answer: D

11.

Which of the following statements about a force are correct? It

I. is measured in newtons.

II. is measured in newton-metre.

III. can start a motion.

IV. can change the direction of a moving body.

A.

I and II only

B.

I and III only

C.

I, III and IV only

D.

I, II, III and IV

Answer: C

12.

A ray of light makes an angle of 20o with the surface of a plane mirror. Determine the angle of reflection.

A.

20o

B.

50o

C.

70o

D.

90o

E.

120o

Answer: C

Angle of incidence = Angle of reflection

20o + Angle of incidence = 90o

Angle of incidence = 90 - 20
Angle of incidence = 70o

Angle of incidence = Angle of reflection
Angle of reflection = 70o

13.

On heating a certain solid in a dry container, all the substance was lost without passing through the liquid state. This means the

A.

solid can easily melt

B.

solid is an alloy

C.

solid cannot stand heat

D.

solid particles are held together by weak forces

E.
solid undergoes sublimation

Answer: E

14.

The main function of petals in a flower is to

A.

protect the ovary.

B.

produce seeds.

C.

attract insects.

D.

secret nectar.

E.

produce sweet scent.

Answer: C

15.

The arrow in the circuit symbol of either n-p-n or p-n-p transistor is always on the

A.

base lead.

B.

collector lead.

C.

emitter lead.

D.

receiver lead.

Answer: C

16.

Which of the following is not a function of the lens in the human eye? It

A.

allows light rays to pass through it

B.

refracts the light rays passing through it

C.

helps to focus the image onto the retina

D.

becomes thinner when focusing a distant object

E.
reflects part of the light rays falling on it

Answer: E

17.

The chief source of energy in the world today is

A.

coal

B.

crude oil

C.

natural gas

D.

uranium

E.
water

Answer: B

18.

Which of the following methods of treating water makes it soft?

A.

Addition of alum

B.

Addition of sodium carbonate

C.

Chlorination

D.

Filtration

Answer: B

19.

The best reason why a cooking pan should have a wooden handle is that, wood is a

A.

good conductor of heat

B.

bad conductor of heat

C.

good radiator of heat

D.

bad radiator of heat

E.

good reflector of heat

Answer: B

20.

The property of metals which makes them to be easily drawn into thin wires is known as

A.

conductivity.

B.

ductility.

C.

malleability.

D.

resistivity.

Answer: B

21.

Which of the following human activities causes pollution of the environment?

A.

Cutting down timber in the forest for firewood

B.

Overgrazing of the field by cattle

C.

Burning of coal and petrol in industries

D.

Building dams across rivers

E.
Destruction of diseased crops

Answer: C

22.

Which of the following source(s) of energy is/are renewable?

I. Solar

II. Crude oil

III. Wind

A.

I only

B.

I and II only

C.

I and III only

D.

I, II and III

Answer: C

23.

The thorns found on some plants are used for

A.

breathing.

B.

protection.

C.

absorbing water from the air.

D.

resisting bush fires.

Answer: B

24.

The characteristics of a fertile soil include good

I. aeration,

II. texture,

III. water-holding capacity.

A.

I only

B.

I and II only

C.

II and III only

D.

I, II and III

Answer: D

25.

The types of energy produced when the hands are vigorously rubbed against each other are

A.

chemical and electrical energy.

B.

heat and sound energy.

C.

heat and light energy.

D.

electrical and light energy.

Answer: B

26.

Which of the following activities illustrates distillation?

A.

Preparation of soup

B.

Preparation of akpeteshie

C.

Tapping of palm wine

D.

Preparation of starch

E.
Freezing of water

Answer: B

27.

A patient has been diagnosed of hypertension. Which of the following readings is most likely the patient's blood pressure?

A.

110/85

B.

120/80

C.

130/85

D.

140/90

Answer: D

Normal blood pressure is generally considered to be less than 120/80 mmHg according to the National Institutes of Health (NIH). Blood pressure readings are expressed as two numbers: systolic (the top number) and diastolic (the bottom number). Systolic pressure measures the force of blood against artery walls when the heart beats, while diastolic pressure measures the force when the heart is at rest between beats.

Hypertension, also known as high blood pressure, is a condition where the force of blood pushing against the artery walls is consistently too high. This can lead to serious health problems if left untreated, such as heart disease, stroke, and kidney disease. High blood pressure is often a silent condition, meaning many people don't experience noticeable symptoms. Hypertension (high blood pressure) is when the pressure in your blood vessels is too high (140/90 mmHg or higher)

28.

Which of the following energy changes takes place in ringing bell?

A.

Potential to kinetic

B.

Potential to sound

C.

Mechanical to sound

D.

Sound to light

Answer: C

The mechanical energy is used to vibrate the metallic body of the ring-bell. When the bell vibrates, it produces sound energy.

29.

The best method for checking erosion on a slope is

A.

cover cropping.

B.

mixed cropping.

C.

contour ploughing.

D.

mulching.

Answer: C

30.

Which of the following organisms is an ecto-parasite of animals?

A.

Fleas

B.

Tapeworm

C.

Liver fluke

D.

Roundworm

Answer: A

Ectoparasite: parasites that live on the surfaces of host organisms or in the skin and do not invade the inner body

Examples of ectoparasites

Fleas, head lice and bed bugs

Endoparasite

Endoparasites are parasites which live inside a host and generally inhabit areas such as the gut, lungs, heart and blood vessels.

Examples of endoparasites

Tapeworm, fluke and roundworm

31.

A substance is termed combustible if it

A.

easily catches fire.

B.

dissolve common salt.

C.

sublimes at room temperature.

D.

boils at 100oC.

Answer: A

32.

The chemical formula of an aluminium sulphide is AlyS3.Determine the value of y

A.

1

B.

2

C.

3

D.

4

Answer: B

When writing the chemical formula, the element(s) or compound(s) exchange their valencies.The sulphur has that of the aluminium element's valency (3) and so the value of y will also be the valency for sulphur

The atomic number for sulphur is 16 so on the electronic configuration, sulphur will have 2,8 and 6 on the last shell.

In order for sulphur to attain stability, it has to gain 2 electrons to make it 8 in the last shell, hence the valency of sulphur is 2 and so the value of y will be 2 (the valency of sulphur)

NOTE: The atomic number for aluminium is also 13, hence the electronic configuration will be 2,8 and 3. Aluminium could lose its 3 electrons in order to be stable, hence the valency of aluminium is also 3

Hence the chemical formula for aluminium sulphide is Al2S3

33.

Which of the following processes about all living things is/are true?

I. Reproduction
II. Respiration
III. Locomotion
IV. Excretion

A.

I only

B.

I and II only

C.

III and IV only

D.

I, II and III only

E.

I, II and IV only

Answer: E

34.

Food substances are transported from the leaves to various parts of a plant through the

A.

cambium.

B.

epidermis.

C.

phloem.

D.

xylem.

Answer: C

TRANSPOT SYSTEM IN PLANTS

35.

The anemometer is an instrument used in determining

A.

amount of rainfall.

B.

speed of wind.

C.

relative humidity.

D.

intensity of light.

Answer: B

36.

The chemicals used in the preparation of ammonia in the laboratory are

A.

ammonium chloride and calcium hydroxide.

B.

ammonium nitrate and sodium chloride.

C.

ammonium sulphate and calcium chloride.

D.

ammonium sulphate and sodium chloride.

Answer: A

37.

Which of the following statements about pressure in liquids is/are correct?

I. Pressure in liquids at the same level acts equally in all directions.

II. Pressure in liquids depend on the area of the liquid.

III. Pressure in liquids decreases with depth.

A.

I only

B.

II only

C.

I and III only

D.

I, II and III

Answer: A

Pascal's law states that pressure in liquids is transmitted equally in all directions.

Pressure in liquids does not depend on the surface area.

The pressure exerted by a liquid increases with depth.

38.

The farming practice which would improve soil fertility is

A.

clean weeding.

B.

crop rotation.

C.

continuous cropping.

D.

mono cropping.

Answer: B

Importance of crop rotation

1. Increases soil fertility/Adds nitrogen to soil
2. Enhances soil structure
3. Prevents soil erosion
4. Improves soil nutrients and nutrient uptake regulation
5. Controls the spread of pests and diseases
6. Controls weed easily
7. There is effective use of the land
8. Harvest of different types of crops on the same piece of land

39.

Which of the following particles constitute matter?

I. Atoms

II. Molecules

III. Ions

A.

I only

B.

II only

C.

II and III only

D.

I, II and III

Answer: D

40.

The mineral salts in dead organisms become available to the soil through

A.

Decomposition

B.

Diffusion

C.

Fermentation

D.

Leaching

E.

Manuring

Answer: A

THEORY QUESTIONS

1.

(a)

(i)

What is refraction of light?

(ii)

Sketch a diagram to show the path of a light ray when it travels from air to glass.

(b)

Explain why it is difficult to separate iron and sulphur mixture after strong heating.

(c)

(i)

Give two examples of digestive enzymes produced in humans.

(ii)

For each of the enzymes given in (i), name the part of the human body where the enzyme is produced.

(d)

List four methods of applying fertilizers to crops.

(a)

(i)

Refraction of light is the bending/change in direction/change in velocity of light as it travels from one medium to another.

(ii)

(b)

Why it is difficult to separate iron and sulphur mixture after strong heating

It leads to a chemical change resulting in the formation of a compound (iron sulphide)/a compound is formed.

(c)

Name of enzyme Part of the human body where it is produced
Ptyalin Salivary gland
Amylase Pancreas/Small intestine
Pepsin Stomach
Rennin Stomach
Lipases Pancreas/Small intestine
Trypsin Small intestine

(d)

Methods of applying fertilizers to crops

1. Ringing
2. Side placement/side dressing
3. Foliar/aerial application/spraying
4. Inter-raw placement
5. Band placement
6. Drilling
7. Broadcasting
8. Through irrigation water/fertigation
9. Top dressing

2.

(a)

Define the following terms and give one example of each:

(i)

Compound

(ii)

Mixture

(iii)

Element

(iv)

Solute

(b)

What energy changes take place in the following processes?

(i)

A mango drops from a tree.

(ii)

A carpenter hits a nail with a hammer.

(iii)

A torch is switched on.

(c)

(i)

Draw a well labeled diagram of a flower

(ii)

Of what importance is the flower to the plant?

(d)

Name the sense organs and state one function of each.

(a)

(i)

A compound is the substance formed as a result of the chemical combination of two or more elements.

OR

A compound is a substance which is made up of two or more elements chemically combined.

Examples of compounds

1. Water/H2O
2. Common salt/Sodium chloride/NaCl
3. Carbon dioxide/CO2
4. Ammonia/NH3
5. Cupric oxide/Copper (II) oxide/CuO
6. Sulphuric acid/H2SO4
7. Sodium hydroxide/NaOH
8. Ammonium chloride/NH4Cl
9. Hydrochloric acid/HCl
10. Copper (II) sulphate/Copper (II) tetraoxosulphate (VI)/CuSO4
11. Iron (II) chloride/FeCl3
12. Magnesium chloride /MgCl2
13. Iron (II) sulphide/FeS
14. Ammonium hydroxide/NH4OH
15. Calcium carbonate/CaCO3
16. Calcium chloride/CaCl2
17. Silver chloride/AgCl
18. Sodium tetraoxosulphate (VI)/Na2SO4
19. Sodium nitrate/Sodium trioxonitrate (V)/NaNO3
20. Potassium sulphate/Potassium tetraoxosulphate (VI)/K2SO4

(ii)

A mixture is what is formed when two or more substances are combined physically

OR

A mixture is the substance formed as a result of the physical combination of two or more substances which can be separated by physical means.

Examples of mixtures

1. Air
2. Salt solution
3. Sugar solution
4. Common salt and sand mixed together
5. Muddy water
6. Alcohol and water mixed together
7. Powdered charcoal and iron filings mixed together
8. Powdered chalk and water mixed together
9. Iodine and sand mixed together
10. Sodium chloride/common salt and sand mixed together
11. Sawdust and iron filings mixed together
12. Powdered charcoal and water mixed together
13. Brass
14. Bronze

(iii)

An element is a substance that is made up of atoms of the same kind.

OR

An element is a substance that cannot be broken down into any simplier form (by any known chemical means).

Examples of elements (First 20 elements)

Atomic Number Element Symbol
1 Hydrogen H
2 Helium He
3 Lithium Li
4 Beryllium Be
5 Boron B
6 Carbon C
7 Nitrogen N
8 Oxygen O
9 Fluorine F
10 Neon Ne
11 Sodium Na
12 Magnesium Mg
13 Aluminium Al
14 Si Silicon
15 Phosphorus P
16 Sulphur S
17 Chlorine Cl
18 Argon Ar
19 Potassium K
20 Calcium Ca

(iv)

Solute is a substance that dissolves in a solvent.

Examples of solute

1. Sugar
2. Salt
3. Washing powder/Soap
4. Ink stain
5. Oil paint
6. Iodine
7. Starch

(b)

Energy changes

(i)

A mango drops from a tree

Potential energy → Kinetic energy → Sound energy + Heat energy

(ii)

A carpenter hits a nail with a hammer

Chemical energy → Potential energy → Kinetic energy → Sound energy + Light energy

(iii)

A torch is switched on

Chemical energy → Electrical energy → Light energy + Heat energy

(c)

(i)

Labeled diagram of a flower

(ii)

The flower is the main sexual reproductive organ of the plant.

(d)

Sense organs and their function

Sense Organ Function
Skin For touching
Ear For hearing
Eye For sight
Nose For smelling
Tongue For tasting
3.

(a)

In an experiment, as in the set-up above, two glass containers A and B of different sizes are joined together with a tube and clipped.

Water is poured into container A to a height of 30 cm and a red liquid is poured into B to a height of 10 cm. The clip is then removed so that the liquids join together.

(i)

State two observations that will be made immediately the clip is removed.

(ii)

Explain the observations in (i).

(iii)

What two observations will be made after a long time? Explain.

(b)

The set-up below is used in the preparation of ammonia gas in the laboratory

Study it and answer the questions that follow.

(i)

Name the parts labelled a, b and c

(ii)

What is the meaning of the arrow sign d?

(iii)

What is the function of the calcium oxide?

(iv)

Why has c been tilted downwards?

(v)

State the method by which the gas is collected.

(vi)

How will you test for the gas?

(vii)

Give the names and the chemical formulae of the compounds that form the content of c.

(c)

In an experiment, a leaf that is partly green and partly yellow is plucked from a tree and the leaf is

I boiled for a minute,

II dipped in warm alcohol,

III washed in cold water,

IV dipped in iodine solution.

One part of the leaf turns blue-black after the dipping in iodine solution while the other part remains unchanged.

(i)

Explain why each of the processes I, II and III

(ii)

Which part of the leaf turns blue-black? Explain.

(iii)

Why does the other part of the leaf not change colour?

(iv)

What conclusion can you draw from the experiment?

(a)

(i)

1. The level of water decreases and the level of the red liquid rises
2. Red liquid moves/diffuses into the water

(ii)

1. Water is at a higher potential/level/pressure so it moves in the direction of lower potential/level/pressure
2. Molecules of red liquid at a higher concentration moves towards region of lower concentration/molecules of red liquid diffuse into the water

(iii)

1. The level of the liquids will be the same/motion of the liquids stop (greater than 10 cm but lower than 30 cm) because the same pressure will be exerted by the liquids in A and B
2. The colour of the liquid in A and B will be uniform/same (pale/light red) because the concentration will be the same

(b)

(i)

a → ammonia gas
b → gas jar
c → round bottomed flask

(ii)

The meaning of the arrow sign d is heating

(iii)

The calcium oxide dries the gas produced

(iv)

c is tilted downwards to prevent condensed water from falling back into the hot flask/to cause cracking

(v)

Upward delivery/downward displacement of air

(vi)

Test for the ammonia gas

Damp/moist red litmus paper turns blue in the presence of the (ammonia) gas

OR

Gas produces fumes with HCl vapour/concentrated hydrochloric acid

OR

Gas has pungent/choky/urinal smell

(vii)

1. Calcium hydroxide (Ca(OH)2)/Sodium hydroxide (NaOH)

2. Ammonium chloride/Ammonium salt (NH4Cl)

(c)

(i)

I → to kill cells/stop photosynthetic process
II → to remove green pigment/decolourized
III → to wash off the alcohol/to soften the leaf

(ii)

The green part turns blue-black because photosynthesis took place in the green part to produce starch

(iii)

The other (yellow) part of the leaf not change colour because it does not contain chlorophyll/green pigment which will trap sunlight for photosynthesis to occur

(iv)

Presence of chlorophyll/green pigment in leaf is required/necessary for photosynthesis/production of starch to take place/occur

4.

(a)

(i)

What is germination of seed?

(ii)

State two conditions necessary for the germination of seed.

(b)

State four methods used in identifying farm animals.

(c)

Explain why it is easier to cut a piece of yam with a sharp knife than with a blunt knife.

(d)

State three differences between a metal and a non-metal.

(a)

(i)

Germination of seed is the sprouting/growth/development of the embryo/seed to produce a new plant/seedling.

(ii)

Conditions necessary for the germination of seed

1. Nature of seed coat
2. Water/moisture
3. Air/Oxygen
4. Suitable/optimum temperature/warmth
5. Viability of the seed
6. Enzymes
7. Sunlight/light
8. Dormancy period

(b)

Methods used in identifying farm animals

1. Tattooing
2. Banding
3. Ear tagging
4. Clipping
5. Leg tagging
6. Dyeing
7. Ear notching/punching
8. Implantation of microchips/radio transmitter

(c)

Why it is easier to cut a piece of yam with a sharp knife than with a blunt knife

Pressure is inversely proportional to the surface area.

Pressure = Force Area

Pressure ∝ 1 Area

With the same force, the smaller the surface area, the greater the pressure.

A sharp knife has a smaller surface area than a blunt knife. The same force used on each knife, will give greater pressure on the sharp knife than the blunt knife (smaller pressure) making cutting easier.

(d)

Differences between a metal and a non-metal

# Metal Non-metal
1. Normally solid Can be solid or liquid or gas
2. Corrosive Non corrosive
3. Attracted by magnet Not attracted by magnet
4. Conducts electricity Does not conduct electricity/poor conductor of electricity
5. Conducts heat/good conductor of heat Does not conduct heat/poor conductor of heat
6. Malleable Not malleable
7. Ductile Not ductile/Brittle
8. High density Low density
9. High melting point Low melting point
10. Has shinning/lustre surface Has dull surface
11. Gives out electrons (forms cations) as reducing agent Receives/accepts electrons (forms anions) as oxidizing agent
12. High tensile strength Low tensile strength
5.

(a)

In an experiment, a pupil took two empty Milo tins and made holes in their sides as shown in the diagram above. The pupil then filled the Milo tins with water.

(i)

Draw and label the diagrams to show what the pupil will observe in set-up A and set-up B.

(ii)

Explain the observations in set-up A and set-up B.

(iii)

What is the aim of set-up A?

(iv)

What is the aim of set-up B?

(b)

In an experiment, equal volumes of dilute hydrochloric acid (Solution A) and dilute sodium hydroxide (Solution B) are mixed together to form solution C.

(i)

What is the volume of solution C?

(ii)

Red litmus paper and blue litmus paper are dipped in turns into solutions A, B and C.

State the observations you will make in all six cases.

(iii)

Give the name of the reaction that took place between solution A and solution B.

(iv)

Identify solution C

(v)

State what will happen when solution C is heated.

(c)

The table below gives the steps that were followed in an experiment to test for starch in a green leaf freshly taken from a tree.

Stages in the test for starch

I.

Leaf is put into boiling water for 1 minute

II.

Leaf is dipped in alcohol warmed in a hot water bath

III.

Leaf is washed in cold water

IV.

Leaf is dipped into iodine solution

(i)

State the reason for carrying out each of the activities in stages I, II and III.

(ii)

What happens when the leaf is dipped in iodine solution?

(iii)

Give the colour changes of the leaf from the beginning of the experiment to the end of the experiment.

(iv)

Why is the alcohol warmed indirectly in a water bath?

(vi)

Explain what will be observed if the test is carried out on a leaf taken from a plant kept in a dark room for 1 day

(a)

(i)

(ii)

Observations in set-up A

The pressure of the water coming out of the lower hole is higher than the one at the top.

Observations in set-up B

The pressures of the water coming out of the holes are the same because they are at the same level.

(iii)

The aim of set-up A is to show that pressure increases with depth in a liquid.

(iv)

The aim of set-up B is to show that pressure at the same point/level in a liquid is the same.

(b)

(i)

The volume of solution C = Volume of solution A + Volume of solution B

The volume of solution C = 20 cc + 20 cc

The volume of solution C = 40 cc

(ii)

Solution Red Litmus Blue Litmus
Solution A No change in colour/remains red Turns red
Solution B Turns blue No change in colour/remains blue
Solution C No change in colour/remains red No change in colour/remains blue

(iii)

Neutralization reaction

(iv)

Sodium chloride solution/NaCl solution/salt solution/brine

(v)

The water evaporates leaving solid sodium chloride/NaCl

OR

Solid sodium chloride/NaCl/common salt is formed

OR

Solution becomes concentrated

(c)

(i)

I → to stop further starch formation/stop photosynthesis process/kill the cells
II → to remove the green pigment/to decolourize the leaf/to remove chlorophyll
III → to soften the leaf

(ii)

Leaf turns blue black

(iii)

Green → colourless/white → blue black

(iv)

The alcohol will catch fire when heated over naked fire.

(vi)

No blue black colour will be seen/colour of iodine will be seen because starch is absent.

6.

(a)

Define the following terms and give one example of each:

(i)

Element

(ii)

Mixture

(iii)

Compound

(b)

Explain the following terms:

(i)

Work

(ii)

Energy

(c)

State the units in which each of the following are measured:

(i)

Power

(ii)

Energy

(iii)

Electric current

(iv)

Temperature

(d)

A body of mass 100 kg is placed at a point 2 m above the ground. What is the potential energy of the body with reference to the ground?

[Take g = 10 ms-2]

(e)

State three characteristics of each of the following:

(i)

An insect pollinated flower

(ii)

A wind pollinated flower

(a)

(i)

An element is a substance that cannot be broken down/split into simpler substances by any known chemical means.

Examples of elements (First 20 elements)

Atomic Number Element Symbol
1 Hydrogen H
2 Helium He
3 Lithium Li
4 Beryllium Be
5 Boron B
6 Carbon C
7 Nitrogen N
8 Oxygen O
9 Fluorine F
10 Neon Ne
11 Sodium Na
12 Magnesium Mg
13 Aluminium Al
14 Si Silicon
15 Phosphorus P
16 Sulphur S
17 Chlorine Cl
18 Argon Ar
19 Potassium K
20 Calcium Ca

(ii)

Mixture is what is formed when two or more substances are put together/combine physically.

Examples of mixtures

1. Air
2. Salt solution
3. Sugar solution
4. Common salt and sand mixed together
5. Muddy water
6. Alcohol and water mixed together
7. Powdered charcoal and iron filings mixed together
8. Powdered chalk and water mixed together
9. Iodine and sand mixed together
10. Sodium chloride/common salt and sand mixed together
11. Sawdust and iron filings mixed together
12. Powdered charcoal and water mixed together
13. Brass
14. Bronze

(iii)

A compound is the substance formed as a result of the chemical combination of two or more elements.

OR

A compound is a substance which is made up of two or more elements chemically combined.

Examples of compounds

1. Water/H2O
2. Common salt/Sodium chloride/NaCl
3. Carbon dioxide/CO2
4. Ammonia/NH3
5. Cupric oxide/Copper (II) oxide/CuO
6. Sulphuric acid/H2SO4
7. Sodium hydroxide/NaOH
8. Ammonium chloride/NH4Cl
9. Hydrochloric acid/HCl
10. Copper (II) sulphate/Copper (II) tetraoxosulphate (VI)/CuSO4
11. Iron (II) chloride/FeCl3
12. Magnesium chloride /MgCl2
13. Iron (II) sulphide/FeS
14. Ammonium hydroxide/NH4OH
15. Calcium carbonate/CaCO3
16. Calcium chloride/CaCl2
17. Silver chloride/AgCl
18. Sodium tetraoxosulphate (VI)/Na2SO4
19. Sodium nitrate/Sodium trioxonitrate (V)/NaNO3
20. Potassium sulphate/Potassium tetraoxosulphate (VI)/K2SO4

(b)

(i)

Work is said to be done when an application of a force moves an object through a distance in the direction of the force

OR

Work is said to be done when a force moves a body through a distance in the direction of the force.

(ii)

Energy is the ability to do work.

(c)

Units of measurement:

(i)

Power → Watts (W)

(ii)

Energy → Joules (J)

(iii)

Electric current → Amperes (A)

(iv)

Temperature → Kelvin (K)/Degree celsius (°C)

(d)

Potential energy = Mass (m) x Acceleration due to gravity (g) x Height (h)

Mass (m) = 100 kg
Acceleration due to gravity (g) = 10 ms-2
Height (h) = 2 m

Potential energy = 100 kg x 10 ms-2 x 2 m
Potential energy = 2000 J

(e)

i)

Characteristics of an insect pollinated flower

1. Petals are large
2. Petals are brightly coloured
3. The flower is usually scented
4. The flower has nectar
5. Stigma is inside the flower
6. Stigma is compact and sticky
7. Pollen grains produced per anther are few
8. Pollen grains are sticky, large, rough and heavy
9. Filaments are short and stout

ii)

Characteristics of a wind pollinated flower

1. Have less brightly coloured petals/petals are dull in colour
2. Petals are small in sizes and not easily seen or absent
3. The flower lacks nectar
4. The flower is not scented
5. Large amount of pollen grains are produced per anther
6. Have feathery/hairy stigma
7. Stigma hangs down to be able to catch pollen grains floating in the air
8. Pollen grains are small, light or dry and smooth
9. Filaments are long and flexible