BECE Science Practical Questions

he below are B.E.C.E Science Practical Questions. We trust they help you in your exam preparations.

 

1.     In an experiment, four nails 1, 2, 3 and 4 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

 

 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]

 

2.      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.

 

 

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 in set-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]

 

3.           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 sometime while leaf B was from a plant placed in a dark cupboard for 24 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 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

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

(iv)         Suggest an aim for the experiment.

                                                                                                                                                [10 marks]

 

 4.      

 

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.

5. 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 labeled 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.

 

6. 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 is carried out.

(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?

 

7. (a) The diagram below is used to demonstrate an activity in the
laboratory.

Study it carefully and use it to answer the questions that follow:



(i) What does the diagram represent? 

(ii) Identify the components labelled D, E, K and P in the diagram 

(iii) State one function each of the parts labelled D, E, K and P. 

(iv) Mention the energy transformation that occurs in E in the diagram when
K is closed.
                                                                                                                [10 marks] 

8. In an experiment, red and blue litmus papers were dipped separately into three test tubes each containing one of the test substances listed in the table below. 

Test substances	Observations		Conclusion
	Red litmus paper	Blue litmus paper
Lemon juice
Calcium hydroxide solution
Dilute hydrochloric acid

(i) Copy and complete the table by making the necessary observation and
conclusion for each substance.

(ii) Name two of the test substances that would react with each other to
produce salt and water.

(iii) Write down a balanced chemical equation for the reaction in (ii)
above.
                                                                                                                            [10 marks]

9. The diagram below is an illustration of the human digestive system.
Study it carefully and use it to answer the questions that follow: 

 

(i) Name the parts labelled I, II, III and IV 

(ii) State one function of each of the parts labelled V and VI 

(iii) Name the part where the digestion of protein starts.

(iv) Identify the part where
       (α) absorption of end-products of digestion takes place

       (β) re-absorption of water takes place
       (γ) egestion takes place
                                                                                                                                        [10 marks] 

10. The diagram below is an illustration of a simple farm tool.
Study it carefully and use it to answer the questions that follow:




(i) Identify the tool 

(ii) State three uses of the tool 

(iii) Mention three ways of maintaining the tool
                                                                                                                [10 marks]