Set 17 Chemistry [Paper] 2

1 SECTION A (60 Marks) Answer only three questions from this section . 1. An organic compound T on combustion yielded 13.2g of carbon dioxide and 2.7 g of water. When 4.7g of T was vaporized at 273ᵒc and at 760 mmHg , it occupied a volume of 2.4 x 10-3m3. a) i) Calculate empirical formula of T. (02 marks) ii) Determine the molecular formula of T. (02½ marks) b) T burns with a sooty flame. Identify T. (0½ mark) c) Discuss the reactions of T with : (@04½ marks) i) Bromine . ii) Propene . iii) Ethanoyl bromide . (You answer should include conditions for the reactions and mechanisms for the reactions where possible) d) Write equations to show how T can be synthesized from benzaldehyde. (01½ marks) 2. a) What is meant by the terms? (@01 mark) i) Order of reaction ii) Half – life of a reaction b) The rate equation for the reaction. S2O32- (aq) + 2H+ (aq) S(s) + SO2(g) + H2O(l) Rate = K[S2O32-][H+]2 i) State how the rate will be affected if the concentrations of the reactants are both doubled . (02 marks) ii) Describe an experiment to determine the order of the reaction with resp ect to S2O32- in the laboratory. (06 marks) c) The table below show s the kinetic data for the reaction between hot aqueous potassium hydroxide and alkylbromide , C4H9Br. 2 Experimental num bers [C4H9Br]/moldm-3 [KOH ]/moldm-3 Initial rate /moldm-3s-1 1 1.0 x 10-3 1.0 x 10-3 5.0 x 10-8 2 2.0 x 10-3 1.0 x 10-3 1.0 x 10-7 3 2.0 x 10-3 2.0 x 10-3 2.0 x 10-7 C4H9Br(l) + KOH(aq) C4H9OH(aq) + KBr(aq). i) Determine the overall order of reaction. (01 mark) ii) Determine the rate constant for the reaction and state its units. (02 …