CIE Jun 2016 v3 Paper 4 Q3

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One method of producing hydrogen from natural gas is the reaction between hydrogen sulfide and methane. PMT 2H2S(g) + CH4(g) CS2(g) + 4H2(g) (a) Write the expression for Kp for this reaction, and state its units. Kp = units[2] (b) The initial partial pressures of the two gases in a mixture at 1000 K are recorded. H2S(g) 200 atm CH4(g) 100 atm The mixture is left to reach equilibrium. It is found that the equilibrium partial pressure of CS2(g) is 2 atm and that of the remaining CH4(g) is 98 atm. (i) Calculate the equilibrium partial pressures of H2S(g) and H2(g). (ii) Calculate the value of Kp at this temperature. p(H2S) =atm p(H2) =atm [2] Kp =[1]UCLES 2016 9701/43/M/J/16<br /> PMT (c) (i) Predict the sign of S o for this reaction. Explain your answer. 2H2S(g) + CH4(g) CS2(g) + 4H2(g) H o = +241 kJ mol1[1] The free energy change, G o, for this reaction at 1000 K is +51 kJ mol1. (ii) Calculate the value of S o for this reaction, stating its units. S o =units[2] (d) How would the value of G o, and hence the spontaneity (feasibility) of this reaction change as the temperature increases? Explain your answer.[2] [Total: 10]UCLES 2016 9701/43/M/J/16 [Turn over<br />

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