BECEzone

THE WEST AFRICAN EXAMINATIONS COUNCIL
GHANA

Basic Education Certificate Examination

SCIENCE 2007

THEORY QUESTIONS

ESSAY

This paper is in two sections, A and B
Answer Question 1 in Section A and any other three questions in Section B.
Credit will be given for clarity of expression and orderly presentation of material


PART I
[40 marks]


Answer all of Question 1

    1. In an experiment, an iron bar is magnetized by dragging a magnet over the surface of the bar from end A to end B several times as shown in the diagram below.

      a diagram of magnetization

      1. Mention the method of magnetization

      2. Give the polarity of the ends A and B of the bar after the magnetization.

      3. How will you test that the bar AB is a magnet?

      4. Indicate how you will test for the poles of A and B of the bar.

      5. Give one precaution that should be taken during the magnetization process.

      6. Name one other method of magnetization

    2. The set-up below is used to prepare gases in the laboratory

      1. Give the names of the parts labelled I, II, III and IV.

      2. Write down the two names of the method of gas collection.

      3. Explain how the gas collects over the water.

      4. Name two gases that can be prepared using the set-up.

    3. The set-up below shows air being breathed out through the mouth into test-tube containing lime water.

      1. Why does the lime water turn milky?

      2. Identify the milky substance produced.

      3. Write a balanced chemical equation for the reaction.

      4. Name two other substances present in breathed-out air.

      5. What is the aim of the experiment?

BackSECTION B