Chemistry Past Questions and Answers

(a) Give one physical property of
(i) diamond;
(ii) graphite
(b) Give two uses of diamond
(c) evidence that shows that both graphite and diamond are allotropes of carbon.

(a) Give two characteristic features of boiling
(b) What will be the effect of the following on the boiling point of water:
(i) addition of crystals of sodium chloride,
(ii) reduction of the atmospheric pressure?
(c) State two ways in which boiling differs from evaporation.

(a) Write the formula of the oxide of nitrogen in which nitrogen has oxidation number of (i) +1;
(ii) +2;
(iii) +3;
(iv) +4;
(b) State which of the oxides in (a) above is/are: (i) acidic (ii) neutral.

Name the type of chemical process involved in the production of
(a) polythene from ethene
(b) ethene from kerosene fraction of petroleum.
(c) soap from vegetable oils
(d) margarine from vegetable oils

(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.