Waec Chemistry 1989 Past Questions and Answers

Question 41:

• WAEC 1989

(a) Name the gas evolved when dilute hydrochloric acid is added to each of the following solids and the mixture is warmed
(i) sodium trioxocarbonate (IV);
(ii) potassium trioxosulphate (IV);
(iii) iron (II) sulphide.

(b) Name the reagent(s) that you would use to identify the gas in (a)(ii) above.

Question 42:

• WAEC 1989

(a) The half-life of 56/25 Mn is 9.3 x 10\(^3\)S. What does the statement mean?
(b) Give the three types of radiation that are usually emitted by radioactive substances.

Question 43:

• WAEC 1989

Consider the compounds represented as A and B below:

(a) What is the celationship between A and B? (
b) Name A and B.
(c) Will the chemical properties of A and B be the same? Give one reason for your answer.

Question 44:

• WAEC 1989

(a) Name the components of
(i) producer gas; (ii) water gas;
(b) Give the reason why water is a better fuel than producer gas.

Question 45:

• WAEC 1989

(a) State Le Chatelier's principle
(b) Use Le Chetelier's principle to deduce the conditions that favour a high yield of ammonia in the Haber process
(c) Give the chemical test for ammonia.
(d) State what would be observed when aqueous ammonia solution is added to:
(i) zinc chloride solution, (ii) copper (II) tetraoxosulohate (V) solution
(e) Explain why the H — N — H bond angle in ammonia is less than that of H — C — H in methane
(f) Give two uses of ammonia.