CIE Jun 2013 v2 Paper 4 Q1

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Examiners For Use Section A Answer all the questions in the spaces provided. A bromoalkane, RBr, is hydrolysed by aqueous sodium hydroxide. (a) (i) Write a balanced equation for this reaction.(ii) What type of reaction is this?[2] (b) The concentration of bromoalkane was determined at regular time intervals as the reaction progressed. Two separate experiments were carried out, with different NaOH concentrations. The graph below shows the results of an experiment using [NaOH] = 0.10 mol dm3. [RBr] / mol dm3 0.010 0.009 0.008 0.007 0.006 0.005 0.004 0.003 0.002 0.001 50 100 150 200 250 time / min When the experiment was repeated using [NaOH] = 0.15 mol dm3, the following results were obtained. time / min [RBr] / mol dm3 0 40 80 120 160 200 240 0.0100 0.0070 0.0049 0.0034 0.0024 0.0017 0.0012 (i) Plot these data on the axes above, and draw a line of bestt.UCLES 2013 9701/42/M/J/13<br /> Examiners For Use (ii) Use one of the graphs to con rm that the reaction isrst order with respect to RBr. Show all your working, and show clearly any construction lines you draw. (iii) Use the graphs to calculate the order of reaction with respect to NaOH. Show all your working, and show clearly any construction lines you draw on the graphs. (iv) Write the rate equation for this reaction, and calculate the value of the rate constant. rate = [7] (c) Nitric oxide, NO, and bromine vapour react together according to the following equation. 2NO(g) + Br2(g)2NOBr(g) H = 23 kJ mol1 The reaction has an activation energy of +5.4 kJ mol1 . Use the following axes to sketch a fully-labelled reaction pathway diagram for this reaction. Include all numerical data on your diagram. 2NO + Br2 energy / kJ mol1 extent of the reaction [2] [Total: 11]UCLES 2013 9701/42/M/J/13 [Turn over<br />

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