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BECE 2021 Integrated Science Likely Examination Theory Questions and Answers

In the previous article, We’ve given you some BECE 2021 Likely integrated science Objective questions and answers. In this article, we are going to look at some of the BECE 2021 Likely integrated science Theory questions and answers.

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THEORY

This paper is in two sections, A and B

AnswerQuestion1in Section A and any other three questions in Section B. Credit will be given for clarity of expression and orderly presentation of material

SECTION A

[30 marks]

AnswerallofQuestion1

Question 1.

(a)In an experiment, four nails 1, 2, 3 and4 are fixed with candle wax onto a metal bar and one end of the bar is heated by means of boiling water as shown in the diagram below

2009b1

A, B, C, D are thermometers inserted in holes along the bar to measure the temperatures at the various points.

(i) What is the temperature of the boiling water?

(ii) State the observations that will be made about nails 1, 2, 3 and 4

(iii) State the observations that will be made about the temperatures recorded by thermometers A, B, C and D.

(iv) What mode of heat transfer is demonstrated in the experiment

(v) State one effect of heat that is associated with the experiment

(vi) State the aim of the experiment

[10 marks](b) In an experiment, a student took three iron nails and cleaned their surfaces dry, and placed them in three separate test tubes in set-ups A, B, and C as shown in the diagram.

2009b2

After three days the nail in set-up A was found to have rusted while the nails in set-ups B and C did not.

Answer the following questions:

(i) Why was the water inset-up B boiled?

(ii) Explain the function of the oil on top of the water in set-up B. (iii) State the purpose of the rubber stopper in set-up C

(iv) Why did the nail in set-up A rust? (v) Suggest an aim for the experiment.

(vi) From the experiment, explain why oil or grease is applied on the surface of a metal to prevent rusting. [10 marks]

(c) In an experiment the following activities were carried out on two green leaves A and B.

Leaf A was from a plant placed in the sunlight for some time while leaf B was from a plant placed in a dark cupboard for24 hours.

Activity

I. Leaves dipped in boiling water for 1 minute

II. Leaves dipped in warm alcohol

III. Leaves washed in cold water

IV. Leaves dipped into an iodine solution

After dipping in the iodine solution, it was observed that leaf A changed colour while leaf B did not change colour.

Answer the following questions:

(i) Explain why each of the activities I, II, III, and IV was carried out. (ii) State the colour change of leaf A

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(iii) Explain why leaf A changed colour but leaf B did not.

(iv) Suggest an aim for the experiment. [10 marks]

SECTION B

[45 marks]

Answer any three questions from this section

Question 2.

(a) Explain each of the following observations in nature:

(i) In the depths of the ocean where it is always dark,there are no green plants.

(ii) On an island where there areno insects and birds,the pawpaw plant produces onlyflowers but no fruits [6 marks]

(b) Describe how soil is formed. [4 marks]

(c) (i) State the laws of reflection

(ii) Draw a labeled diagram to show the reflection of light on a plane mirror [5 marks]

Question 3.

(a) A child is found not to be able to see at night

(i) What deficiency disease may the child be suffering from? (ii) What food nutrient is the child lacking?

(iii) List two sources of food substances that can provide the nutrient the child lacks.

[4 marks]

(b) (i) What is an atom?

(ii) Name the components of an atom which determines each of the following quantities.

(α) mass of an atom

(β) charge of an atom

(iii) Why is an atom electrically neutral? [5 marks]

(c) (i) What is friction?

(ii) Give two bad effects of friction.

(iii) Give two situations where friction is an advantage [6 marks]

Question 4.

(a) (i) Explain heredity

(ii) Give two examples of heredity characters [5 marks]

(b) Explain whether each of the following processes is a chemical change or a physical change:

(i) Rusting;

(ii) (iii) (iv) Burning; Filtration;

Expansion of copper [4 marks]

(c)

(i) (ii) (iii)

What is a simple machine?

Name two types of simple machines

Explain why the efficiency of a machine cannot be equal to 100% [6 marks]

Question 5.

(a) Study the organisms listed below: Earthworm;

Sheep; Cassava plant; Grasshopper; Man;

Hen.

Draw a food chain using four of the organisms [4 marks]

(b) (i) Name four types of forces apart from friction.

(ii) Give three effects of a force

[7 marks]

(c) A certain pupil in a classroom can see clearly on the blackboard only when he sits at the front. (i) State the eye defect the child is suffering from.

(ii) Explain why the child is unable to see when he is far from the blackboard.

(iii) How can the defect be corrected?

[4 marks]

ANSWERS TO THEORY

Below are the answers to the above integrated science theory questions.

Question 1Ans.

(a) (i) Temperature = 100°C or212°For 373K

(ii) Observations (Nails)

Nails 1, 2, 3, and 4 will drop off one after the other

– Nail1 drops first, nail 2 seconds, nail3 third andnail4fourth

(iii) Observations(Thermometers)

The readings of Thermometers A, B, C, and D will increase progressively till they reach

100°C

– Thermometer A reaches 100°C first, B second, C third, and D fourth

(iv) Mode of heat transfer – Conduction

(v) Effects of heat

  •  Causes increase in temperature(as shown by the thermometer readings)
  • Causes change in state (candle wax melts– changes from solid to liquid)
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(vi) Aim of experiment

  • To show that metals are good conductors of heat
  • To show that heat travels through metals

(b) (i) Why water inset-upBwas boiled

To remove dissolved air /oxygen from the water

(ii) The function of the oil on top of the water inset-up B

  • To prevent air(hence, oxygen) from entering/getting dissolved in the water

(iii) The purpose of the rubber stopper inset- up C

  • To prevent water particles or vapour or moisture from entering and contacting the nail

(v) Aim for the experiment

  • To show that moisture/ water and oxygen/ air are necessary for rusting to occur.

(vi) Why grease is applied on metals to prevent rusting

To prevent moisture and air, which contains oxygen, from getting into contact with the metal, since metals containing iron will rust in the presence of air and moisture.

(c) (i) Why each activity was carried out

I – to kill the plant cells or stop the process of photosynthesis

II – remove the green pigment (chlorophyll)

III – to wash away the alcohol and soften the leaf

IV – to test for starch in the leaf

(ii) Colour change of leaf A

  • From cream /pale yellow / light brown to blue-black

(iii) The blue-black colouration indicates the presence of starch, which means that photosynthesis occurred in leaf to produce starch.

Leaf B did not change in colour because photosynthesis did not occur, and hence, no starch was produced.

Question 2.

(a) (i) Reasons for no green plants in the dark ocean depths

  • No light reaches there, hence no photosynthesis takes place.

(ii)

Reasons for no fruits on pawpaw plant, where there are no insects and birds

  • Since there are no agents of pollination, no pollination takes place; hence, no fertilization takes place. As a result, no fruits are produced.

(b) How soil is formed:

Soil is formed from the disintegration/ breakdown/ weathering of rocks. The broken-down rock particles combine with water, decayed organic matter, air and microorganisms to form soil

(c) (i) Laws of reflection

  • The angle of incidence is equal to the angle of reflection
  • The incident ray, the reflected ray, and the normal, at the point of incidence, all lie in the same plane

(ii) Labelled diagram

i = angle of incidence, r = angle of reflection

Question 3 Ans.

(a) (i) Deficiency disease: Night blindness

(ii)

Food nutrient:

  • Vitamin A

(iii)

Food sources:

Milk, butter, cheese, egg yolk, liver,palm oil, tomatoes, carrots, lettuce,cod-liver oil,

(b) (i) Atom

• The smallest particle of a substance that can take part in a chemical reaction

• The smallest portion into which an element can be divided and still retain its properties

(ii) Components of atom that determine

(α) mass ofatom: protons and neutrons

(β) charge of atom: protons and electrons

(iii) Why an atom is electrically neutral:

Thenumbers of protons and electronsare equal.Thepositivelycharged protons neutralize the negativelychargedelectrons, hence, makingthe atomelectricallyneutral.

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(c) (i) Friction is

The force that opposes the relative sliding motion of two bodies in contact

Or:

The resistance encountered by an object moving relative to another object with which it is

in contact

(ii)

Bad effects of friction

  •  Reduces the efficiency of machines
  •  Causes wear and tear
  • Causes loss of energy through heat generation
  • Slows down sliding motion of a body

(iii)

Situations where friction is an advantage

  • Enables walking, running, etc without slipping
  • Enables vehicles to brake effectively
  • Enables birds to perch on trees without falling
  • Enable wheels to roll on a surface
  • Enables our hands to hold items

 Question 4 Ans.

(a)

(i)

Heredity

The passing on of genetic factors from parents to children through genes:

Or: the transfer of genetically controlled characteristics from one generation to the next in living organisms

(ii)

Examples

Intelligence, shape of nose, height, colour of eyes, etc

(b) Explanationofwhetherchemical or physical change:

(i) Rusting – Chemical change; because a new substance is formed and the change is irreversible

(ii) Burning – Chemical change; because a new substance is formed and the change is irreversible

(iii) Filtration – Physical change; because no new substance is formed and the change is reversible

Question 5.

Gravitational, tensional, centripetal, centrifugal, magnetic, electrostatic, upthrust, cohesive, adhesive

(ii) Effects of a force

• Can cause a moving body to come to rest (stop moving)

• Can cause a body at rest to move

• Can cause a moving body to accelerate

• Can cause a moving body to decelerate

• Can change the direction of a moving body

• Can change the shape of a body

(c) (i) The eye defect: short-sightedness or myopia

(ii)

Explanation

Light rays from a distant object are focused in front of the retina, due to the eye lens being thicker than normal or the eyeball being too long. Hence the brain does not receive the correct information for interpretation and so the child is unable to see.

(iii) How the defect can be corrected: By the use of a concave or diverging lens.

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