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CIE Jun 2013 v3 Paper 2 Q2
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![Examiners For Use Methanol, CH3OH, can be produced industrially by reacting carbon monoxide, CO, with hydrogen, H2. CO(g) + 2H2(g) CH3OH(g) H = 91 kJ mol1 The process is carried out at 4103 kPa (40 atmospheres) and 1150 K. (a) (i) State Le Chatelier's Principle.[2] (ii) From your understanding of Le Chateliers Principle, state the conditions of temperature and pressure that could be used in order to produce an increased yield of methanol in this process. In each case, explain why the yield would increase. temperatureexplanationpressureexplanation[4]UCLES 2013 9701/23/M/J/13<br />
(b) The carbon monoxide for use in the production of methanol may be formed by reacting carbon dioxide with hydrogen. CO2(g) + H2(g) CO(g) + H2O(g) Kc = 1.44 at 1200 K A mixture containing 0.70 mol of CO2, 0.70 mol of H2, 0.30 mol of CO and 0.30 mol of H2O was placed in a 1 dm3ask and allowed to come to equilibrium at 1200 K. Calculate the amount, in moles, of each substance present in the equilibrium mixture at 1200 K. CO2 + H2 CO + H2O 0.70 0.70 0.30 0.30 initial moles Examiners For Use [4] [Total: 10]UCLES 2013 9701/23/M/J/13 [Turn over<br />](https://learnah.org/wp-content/uploads/2018/08/June_2013_v3_QP_-_Paper_2_CIE_Chemistry_A-level_2-0.jpg)
![Page 3 Mark Scheme Syllabus Paper GCE AS/A LEVELMay/June 2013 9701 23 (1) (a) (i) if the conditions of a system in equilibrium are changed the position of equilibrium moves so as to reduce that change (1) [2] (ii) lower temperature because the forward reaction is exothermic higher pressure because the forward reaction shows a reduction in volume or (1) (1) (1) there are fewer molecules/moles on RHS of equilibrium (1) [4] (b) CO2 + H2CO + H2O initial moles equil. moles 0.70 0.70 0.30 0.30 (0.70x) (0.70x) (0.30+x) (0.30+x) (1) equil. concn. (0.70x) 1 (0.70x) 1 (0.30+x) 1 (0.30+x) 1 Kc = (0.30+x)2 = 1.44 (0.70-x)2 gives x = 0.25 at equilibrium, n(CO2) = n(H2) = 0.700.25 = 0.45 moles and n(CO) = n(H2O) = 0.3 + 0.25 = 0.55 moles (1) (1) (1) [4] [Total: 10]Cambridge International Examinations 2013<br />](https://learnah.org/wp-content/uploads/2018/08/June_2013_v3_MS_-_Paper_2_CIE_Chemistry_A-level_2.jpg)