BECE 2002 Integrated Science Paper 2 Essay (July)

     

BECE PAST QUESTIONS AND ANSWERS

BECE 2002 (JULY) INTEGRATED SCIENCE

ESSAY - Paper 2  

Answer three questions only from this section.

Illustrate your answers wherever possible, with large, clear and fully labelled diagrams. Credit will be given for clarity of expression and orderly presentation of material.

All questions carry equal marks



1. (a) Classify each of the following substances as colloids, suspension or solution: Smoke, breast milk, powdered milk in water, sea water, mist, steel.

(b) (i) Define valency

(ii) State the valencies of the following elements and radicals: 

    (α) Iron

    (β) Zinc

    (γ) Hydroxyl

    (λ) Carbonate


(c) Give one difference between plants and animals in terms of

    (i) feeding

    (ii) excretion

    (iii) sensitivity


(d) (i) Draw and label a diagram to show how an image is formed in a pinhole camera.

    (ii) State the characteristics of the image formed.



2. (a) State three differences between molecules in a solid state and liquid state.

    (b) (i) What is a solution?

        (ii) Difference between solutions and mixtures in terms of particle sizes. 

    (c) Name the elements which make up the following compounds:

            (i) water

            (ii) common salt

            (iii) ammonia


(d) Copy and complete the table below

Disease	Vector	Causative agent	Symptoms
Malaria
Sleeping sickness

(e) (i) What is a man-made satellite?

    (ii) Give two examples of natural satellites.

    (iii) Mention two applications of man-made satellites



3. (a) Name the four main parts of a flower.

    (b) Give two external features of plants pollinated by wind.

    (c) Construct a food chain using any four of the organisms listed below.

            Goat, lizard, bird, snake, earthworm, grasscutter, grass, ant, cassava


(d) (i) The energy input of a machine is 7.5 J and the output energy is 5.0 J. Calculate the efficiency of the machine.

        (ii) Explain why the efficiency of a machine is always less than 1.


4. (a) (i) What is an embryo?

        (ii) Where does an embryo develop in the female mammal?

       (iii)  Describe briefly how a developing embryo breathes in oxygen.

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