OCR A Jun 2011 Paper 2 Q4

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4 Atom economy and percentage yield are important factors in deciding the sustainability of a manufacturing process. 10 (a) Complete the expression below for atom economy. atom economy = sum of100% sum of[1] (b) The following five reactions all represent important industrial processes. Process 1 CH3CH2CH2CH2CH2CH2CH2CH3 (CH3)2CHCH2CH2CH(CH3)2 Process 2 CH3CH2OH + CH3COOH CH3COOCH2CH3 + H2O Process 3 CH2CH2 + H2O CH3CH2OH Process 4 NH3 + HNO3 NH4NO3 Process 5 C8H18 C2H4 + C6H14 (i) Which process is an example of cracking?[1] (ii) Which process makes a structural isomer of the reactant?[1] (iii) Which process does not have an atom economy of 100%? Explain your answer.[2]OCR 2011<br />
 (c) The manufacture of ethanol by the fermentation of glucose can be represented by the following equation. 11 C6H12O6(aq) 2C2H5OH(aq) + 2CO2(g) The atom economy is 51.1% and the percentage yield is 88.6%. (i) Suggest two reasons why it is a good idea to find uses for the carbon dioxide produced.[2] (ii) Some scientists believe that it is more important to have a high percentage yield in fermentation but others think that a high atom economy is more important. Is it more important to have high percentage yield or a high atom economy in fermentation? Explain your answer.[2] [Total: 9]OCR 2011 Turn over<br />

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