B.E.C.E – 1990
ESSAY TYPE QUESTIONS

QUESTION 1
a) Define the following terms and give one example of each:
i) Compound
ii) Mixture
iii) Element
iv) Solute

 

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.
Example: Water
Other examples are: Common salt(sodium chloride), Carbon dioxide, Ammonia, etc

ii) A mixture is the substance formed as a result of the physical combination of two or more elements. OR A mixture is formed as a result of the physical combination of two or more other substances which can be separated by physical means. Example: Air Other examples are: Sugar solution, Salt solution etc.

iii) An element is a substance that is made up of the same kind of atoms and cannot be broken down (or split) into simpler substances by any known chemical means. Example: Hydrogen Other examples are: Oxygen, Nitrogen, Carbon, Sodium, Lithium etc.

iv) A solute is a substance that dissolves in another substance called the solvent to form a solution. Example: Sugar Other examples: Salt, Washing powder (soap) etc. Note that these substances dissolve in water. So water is the solvent and they are the solutes.

b) What energy changes take place in the following processes?
i) When a mango drops from the tree
ii) A carpenter hits a nail with a hammer
iii) A torch is switched on

b) i) Potential argy- Kinetic energy → Sound energy + Heat energy

ii) Chemical ergy- Potential energy→ Kinetic gy- Sound energy + Light energy

iii) Chemical energy →→ Electrical energy -> Lightene nergy + Heaten epsilon

c) i) Draw a well labelled diagram of a flower.
ii) Of what importance is the flower to the plant?

c)i) A well labelled diagram of a flower is shown below:

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

d) Name the sense organs and start on function of each.

QUESTION 2
a) i) What is soil erosion? Give two types of soil erosion.
ii) Give three activities of man that can cause soil erosion.
iii) List three ways by which soil can be conserved.

a) i) Soil erosion is the washing away or the removal and carrying away of the top soil by natural agents such as running water, rain or wind.

Two types of soil erosion are Rill Erosion and Sheet Erosion. Note: The following types are also correct: Gully erosion and Splash erosion

ii) Three main activities of man that cause soil erosion are:

1. Road Construction

2. Bush fires or Bush burning

3. Deforestation

Note: Other activities are farming (especially over-cropping), sand wining (i.e. soil removal for building and road construction) and over-grazing.

iii) Three ways by which soil can be conserved are:

1. Application of fertilizer or manure

2. Growing of cover crops

3. Practising crop rotation

Note: Others are practising afforestation and reafforestation, practising bush fallow or land rotation, contour ploughing, erecting windbreaks etc.

b) i) What is a lever?
ii) Classify the following under first class, second class and third class levers.
Sugar tong
Bottle opener
Paper cutter
A pair of scissors
Fishing rod
Claw hammer

b) A lever is a simple machine that consists of any rigid bar or rod which turns freely about a fixed point called a pivot or fulcrum

c) In each of the following activities state
whether the changes that occurred are:
i) physical or chemical
ii) reversible or irreversible
I. Some boiled cassava and plantain were pounded together into fufu.
II. A piece of ice block is put in a cup. After a while, it was found out that the block had changed into a liquid.
III. A clean piece of nail was put into a beaker of water. After five days it was observed that the colour of the nail had changed.

c) i) I = Physical change
II = Physical change
III = Chemical change
ii) I = Irreversible
II = Reversible
III = Irreversible

QUESTION 3
For each of the following diseases, name the causative organism and one method of prevention.
i. Cholera
ii. Bilharzia
iii. Malaria
iv. Tuberculosis

b) Show how you would separate each of the following mixtures:
i) Common salt and sand
ii) Muddy water

i) Dissolve the common salt by adding water to the mixture in a beaker. Stir the mixture. Filter the sand from the salt solution using filter paper in a funnel. Using a Bunsen burner, heat the salt solution to retrieve the salt in an evaporating dish.

ii) Muddy water can best be separated by the process called filtration. This is done by using filter paper, funnel and a beaker. A filter paper is folded into a funnel and the muddy water is poured into the funnel and filtered. The water is collected by the beaker and sand is left on the filter paper.

c) Explain why the planets and their moons move around the sun but they do not clash.

c) The gravitational force of attraction of the sun on the planets and their moons provides the centripetal force that keeps the planets and their moons moving in their respective orbits around the sun without clashing.

d) Give two uses of the sun’s energy in everyday life.

d) Uses of the sun’s energy in everyday life

– The sun provides energy for photosynthesis in plants. panels.

The sun generates energy for solar It is a source of light

It helps the skin produce vitamin D as it shines on the skin

It is used for drying clothes.

QUESTION 4
a) i) What id pollution
ii) Name two types of pollution. For each type give one pollutant and its source.

4a. SOLUTION a) i) Pollution is the release of toxic (harmful or poisnous) substances into the environment.

ii) Types of pollution

b) i) Explain the term vegetative reproduction.
ii) Give two local examples of plants that reproduce vegetatively.

b) i) Vegetative reproduction is the type of reproduction that occurs in a plant when part of the plant other than the seed is used to give rise to new plants capable of existing on their own. OR Vegetative reproduction is a form of reproduction whereby plants produce young ones from growing parts of the parent plant (where there are buds).

II.

c) i) List the part of an atom and show the electrical charges of each of the parts.
ii) Explain the term work.
iii) Distinguish between heat and temperature and give their units.

C.I

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

iii) Heat is the energy which causes rise in temperature of bodies while temperature is the measure of amount of heat in a body or the degree of hotness or coldness of the body. Heat is measured in joules but Temperature is measured in kelvin or degrees celsius.