OCR A Jan 2013 Paper 2 Q5

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5 Chloroethene, CH2CHCl, is made from 1,2-dichloroethane, CH2ClCH2Cl. 12 CH2ClCH2Cl CH2CHCl + HCl equation 5.1 (a) A chemical plant uses 19.80 tonnes of 1,2-dichloroethane to make 11.25 tonnes of chloroethene. Calculate the percentage yield of chloroethene. (1 tonne = 1.00106 g) percentage yield =% [3] (b) The table below shows some average bond enthalpies. Bond Average bond enthalpy / kJ mol1 CH CC C=C CCl HCl +413 +347 +612 +346 +432 Using the average bond enthalpies in the table above, calculate the enthalpy change of reaction, Hr, for equation 5.1.OCR 2013 Hr =kJ mol1 [3]<br />
 (c) Chloroethene is used to make poly(chloroethene), PVC. 13 Write an equation, using displayed formulae, for the reaction to form poly(chloroethene) from its monomer. [3] (d) Waste polymers are often disposed of by combustion. The heat released can be used to generate electricity. (i) Hydrogen chloride, HCl, is a toxic waste product formed by combustion of PVC. Suggest how the HCl can be removed from the gases produced during the combustion of PVC.[1] (ii) Some waste polymers are put into landfill sites. This uses up a valuable resource. State two ways, other than landfill and combustion, of processing waste polymers. 12[2] (iii) Chemists are trying to minimise the environmental damage caused by the disposal of waste polymers by developing new types of polymers. Give an example of a type of polymer being developed to minimise environmental damage.[1] [Total: 13]OCR 2013 Turn over<br />

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