Set 10 Chemistry [Paper] 1

ONLY HARD WORK CAN TURN DREAMS IN TO REAL ITY 1 SECTION A -46 MARKS Attempt all questions in this section. 1. Various concentrations of X and Y were reacted at a constant temperature. The table below shows the initial concentrations of X and Y, and their initial rates for the reaction. Experiments [X] mol/dm3 [Y] mol/dm3 Initial rate (mol/s) 1 0.2 0.2 3.5 x 10-4 2 0.4 0.4 1.4 x 10-3 3 0.8 0.4 5.6 x 10-3 a) State the order of reaction with respect to X and Y. (@0½ marks) i. X: ……………………………………………………………………………………………. ii. Y: ……………………………………………………………………………………………. b) Give reasons for your answers in (a) above. (02 marks) ………………………………………………………………………………………………………… ………………………………………………………………………………………………………… …………………………………………………………………………………………………………. c) Determine the overall order of the reaction. (0½ marks) …………………………………………………………………………………………………………. d) Calculat e the value for the rate constant of the reaction. (01 ½ marks) ………………………………………………………………………………………………………… ………………………………………………………………………………………………………… ………………………………………………………………………………………………………… ………………………………………………………………………………………………………… 2. A solid Q contains 9.37% by m ass magnesium, 10.39% nitrogen, 42.18% water and the rest is oxygen. ONLY HARD WORK CAN TURN DREAMS IN TO REAL ITY 2 a) (i). Calculate the empirical formula of solid Q. (02 marks) ………………………………………………………………………………………………………… ………………………………………………………………………………………………………… ……………………………………………………………………………………………………… … ………………………………………………………………………………………………………… ………………………………………………………………………………………………………… ………………………………………………………………………………………………………… ………………………………………… ……………………………………………………………… ………………………………………………………………………………………………………… (ii).Determine the molecular formula of Q. (01 mark) (RFM of Q = 256 ) ………………………………………………………………………………………………………… ………………………………………………………………………………………………………… ………………………………………………………………………………………………………… b) Solution of Q reacts with freshly prepared iron (II) sulphate in the presence of concentrated sulphuric acid to form a brown ring . Identify Q. (0 ½ mark) …………………………………………………………………………………………………….. c) Write equation for the reaction that would take place if Q was heated. (01½ mark s) …………………………………………………………………………………………………… …………………………………………………………………………………………………… ONLY HARD WORK CAN TURN DREAMS IN TO REAL ITY 3 3. Name a reagent that can be used to distinguish between t he following pairs of compounds and in each case, state what would be observed if each members of …