AQA Jun 2011 Paper 2 Q1

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section a answer all questions in the spaces provided do not write outside the box the rate of a chemical reaction is influenced by the size of the activation energy catalysts are used to increase the rates of chemical reactions but are not used up in the reactions a give the meaning of the term activation energy marks b explain how a catalyst increases the rate of a reaction marks c the diagram below shows the maxwell boltzmann distribution of molecular energies at a constant temperature in a gas at the start of a reaction on this diagram the most probable molecular energy at this temperature is shown by the symbol emp the activation energy is shown by the symbol ea number of molecules emp ea energy wmp jun chem do not write outside the box to answer the questions c i to c iv you should use the words increases decreases or stays the same you may use each of these answers once more than once or not at all c i state how if at all the value of the most probable energy emp changes as the total number of molecules is increased at constant temperature mark c ii state how if at all the number of molecules with the most probable energy emp changes as the temperature is decreased without changing the total number of molecules mark c iii state how if at all the number of molecules with energy greater than the activation energy ea changes as the temperature is increased without changing the total number of molecules mark c iv state how if at all the area under the molecular energy distribution curve changes as a catalyst is introduced without changing the temperature or the total number of molecules d mark for each of the following reactions identify a catalyst and name the organic product of the reaction d i the fermentation of an aqueous solution of glucose catalyst name of organic product marks d ii the hydration of but ene catalyst name of organic product marks turn over wmp jun chem

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