OCR A Jun 2016 Paper 2 Q5

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The hydrocarbons present in crude oil are processed to obtain useful materials, including many fuels. 14 Alkanes with 610 carbon atoms are used in petrol. (a) What is the general formula of an alkane?[1] (b) Carbon monoxide and nitrogen monoxide are pollutants formed in internal combustion engines, using petrol as their fuel. Explain how carbon monoxide and nitrogen monoxide are formed in internal combustion engines. Describe the stages that allow a catalytic converter to reduce carbon monoxide and nitrogen monoxide emissions. Include equations for any reactions and use octane to represent the alkanes present in petrol.[6]OCR 2016<br />
 (c) Oil companies process alkanes into branched and cyclic hydrocarbons to promote efficient combustion in petrol. 15 Draw the structure of one branched and one cyclic saturated hydrocarbon that contains 8 carbon atoms.Name each hydrocarbon. Branched Cyclic name:name:[3] (d) The greenhouse effect of a gas in the atmosphere is dependent on two factors. State these two factors.[2]OCR 2016 Turn over<br />
 16 (e) By 2020, the EU has regulated that a car must emit less CO2 per kilometre than in 2015. A typical car will need to emit 5.6105 g less CO2 in 2020 compared with 2015. Calculate how much less petrol would be consumed by a typical car in 2020 to meet this regulation. Give your answer in litres of petrol (1 litre of petrol has a mass of 700 g). Assume that petrol is liquid octane and that complete combustion takes place, as in the equation below. C8H18 (l) + 12.5 O2 (g) 8CO2 (g) + 9H2O (l) volume of petrol =litres [4] [Total: 16]OCR 2016<br />
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