AQA Jun 2014 Paper 2 Q9

Answers available below

ethanol is an important fuel do not write outside the box a a dilute aqueous solution of ethanol can be produced by the fermentation of an aqueous solution of glucose it is claimed that the ethanol obtained from this solution is a carbon neutral biofuel write an equation for this fermentation reaction give two other essential conditions for this reaction to produce a good yield of ethanol name a process used to produce a much more concentrated solution of ethanol from a dilute aqueous solution state the meaning of the term carbon neutral in the context of this biofuel marks extra space question continues on the next page turn over wmp jun chem do not write outside the box b a student carried out a laboratory experiment to determine the enthalpy change when a sample of ethanol was burned the heat produced was used to warm some water in a copper calorimeter the student found that the temperature of g of water increased by c when mol of pure ethanol was burned in air use the student s results to calculate a value in kj mol for the enthalpy change when one mole of ethanol is burned the specific heat capacity of water is j k g deduce two reasons why the student s value for the standard enthalpy of combustion of ethanol is different from a data book value of kj mol marks extra space wmp jun chem do not write outside the box c mean bond enthalpies can be used to calculate enthalpies of reaction c i give the meaning of the term mean bond enthalpy marks c ii consider the mean bond enthalpy data in table table c h c c c o o o c o o h mean bond enthalpy kj mol to be calculated use the data in table and the equation shown to calculate a value for the bond enthalpy for the o o double bond in an oxygen molecule marks ch ch oh g o g co g h o g h kj mol end of questions wmp jun chem

Show answer