AQA Jun 2013 Paper 2 Q10

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section b answer all questions in the spaces provided do not write outside the box ethanol is an important industrial compound a ethanol can be produced by the hydration of ethene the equation for the equilibrium that is established is h c ch g h o g ch ch oh g h kj mol the operating conditions for the process are a temperature of c and a pressure of mpa under these conditions the conversion of ethene into ethanol is a i identify the catalyst used in this process deduce how an overall yield of is achieved in this process without changing the operating conditions marks a ii use your knowledge of equilibrium reactions to explain why a manufacturer might consider using an excess of steam in this process under the same operating conditions marks wmp jun chem do not write outside the box a iii at pressures higher than mpa some of the ethene reacts to form a solid with a relative molecular mass greater than deduce the identity of this solid give one other reason for not operating this process at pressures higher than mpa do not include safety reasons marks b write an equation for the reaction that has an enthalpy change that is the standard enthalpy of formation of ethanol marks c when ethanol is used as a fuel it undergoes combustion c i define the term standard enthalpy of combustion marks question continues on the next page turn over wmp jun chem c ii consider these bond enthalpy data do not write outside the box c h c c c o o o c o o h bond enthalpy kj mol use these data and the equation to calculate a value for the enthalpy of combustion of gaseous ethanol ch ch oh g o g co g h o g marks d gaseous ethanol can be used to convert hot copper ii oxide into copper d i deduce the role of ethanol in this reaction mark d ii draw the structure of the organic compound with mr that is produced in this reaction mark wmp jun chem

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