AQA Specimen Paper 2 Q1

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Answer all questions. This question involves the use of kinetic data to deduce the order of a reaction and calculate a value for a rate constant. The data in Table 1 were obtained in a series of experiments on the rate of the reaction between compounds A and B at a constant temperature. Table 1 [3 marks] Experiment Initial concentration of A / mol dm3 Initial concentration of B / mol dm3 0.12 0.36 0.72 0.26 0.26 0.13 Initial rate / mol dm3 s1 2.10104 1.89103 3.78103 Show how these data can be used to deduce the rate expression for the reaction between A and B. . 1 0 1 Barcode Typesetter code<br /> 0 1 . 2 The data in Table 2 were obtained in two experiments on the rate of the reaction between compounds C and D at a constant temperature. Table 2 Experiment Initial concentration of C / mol dm3 Initial concentration of D / mol dm3 Initial rate / mol dm3 s1 1.9102 3.6102 3.5102 5.4102 7.2104 To be calculated The rate equation for this reaction is rate = k[C]2[D] Use the data from experiment 4 to calculate a value for the rate constant, k, at this temperature. Deduce the units of k. [3 marks] k = Units = . 3 Calculate a value for the initial rate in experiment 5. 0 1 [1 mark] Initial rate = mol dm3 s1 Question 1 continues on the next page Barcode Typesetter code Turn over <br /> 0 1 . 4 The rate equation for a reaction is rate = k[E] Explain qualitatively why doubling the temperature has a much greater effect on the rate of the reaction than doubling the concentration of E. [3 marks] 0 1 . 5 A slow reaction has a rate constant k = 6.51103 mol1 dm3 at 300 K. Use the equation ln k = ln AEa/RT to calculate a value, in kJ mol1, for the activation energy of this reaction. The constant A = 2.571010 mol1 dm3. The gas constant R = 8.31 J K1 mol1. [2 marks] Activation energy = Barcode Typesetter code<br /> Turn over for the next question DO NOT WRITE ON THIS PAGE ANSWER IN THE SPACES PROVIDED Barcode Typesetter code Turn over <br />

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