Chemistry Past Questions and Answers

(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.

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.

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

(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.

(a) List three characteristics of a homologous series
(b) Give one example of;
(i) alkanes; (ii) alkynes.
(c) A hydrocarbon contains 7.7% by mass of hydrogen and 92.3% by mass of carbon. The relative molar mass of the compound is 78.
(i) Derive the empirical formula of the compound and hence its molecular formula.
(ii) Name the hydrocarbon and write its structural formula. (H=1, C=12)
(d) Two hydrocarbons, X and Y were treated separated with acidified potassium tetraoxomanganate (VII) solution. X decolorized the solution and Y did not. Which of X and Y will undergo
(i) substitution reaction only,
(ii) both addition and substitution reactions.
(iii) polymerization?
(e) If ethanol is to be converted into ethanoic acid
(i) What are the conditions required?
(ii) name the type of reaction that will be involved and write the equation