8. Suppose that two gas jars; one containing gas "A" and another one containing gas "B" are made available to you. Gas "A" is used in hardening of margarine whereas gas "B" is used by mountain climbers.
(a) What tests will you conduct to identify each of the two gases?
(b) Give two physical properties and three chemical properties that can be used to distinguish gas "A" from gas "B". (7 marks)
9. Two experiments A and B were conducted to prepare hydrogen gas by varying the size of zinc granules which were reacted with dilute hydrochloric acid. All other factors were kept constant in the two experiments. Data obtained were used to plot the following graph:
(a) Briefly explain the differences in the results of experiments A and B.
(b) What factors can be adjusted to increase the yield of the product? (7 marks)
12. (a) Give three ways in which environmental destruction is likely to occur during extraction of metals.
(b) The following equations represent the steps involved in the conversion stages of iron extraction in Bussener converter. Arrange the equations in chronological order from the first step to the last by writing the respective letter so as to get a complete explanation of the conversion stage.