= 189 70 = 119 JK–1 mol–1 (1) S – = 373 × 119 = 44 KJ mol–1 (1) 4 H (b) spontaneous reaction when 0 G  (1) CH4(g) + H2O(g) CO(g) + 3H2(g) (1)  = 198 + 3 × 131 189 186 = 216 JK–1 mol–1 (1) S – – the entropy change in (1) –TS makes -ve once T is high enough (1) 6 G (c) diamond  graphite S = +3 JK–1 mol–1 (1) since H  0, G is always  0 (1) kinetics: large Ea makes reaction too slow (1) 3 (d) CaO(s) + CO2(g) CaCO3(s)  S = 90 40 214 = JK– mol–1 (1) – – –164 = 0, = TS G H Ts = = 1085 K (1) 2 [15]
S = 189 – 70 = 119 JK–1 mol–1 (1) H = 373 × 119 = 44 KJ mol–1 (1) 4 (b) spontaneous reaction when G  0 (1) CH4(g) + H2O(g)  CO(g) + 3H2(g) (1) S = 198 + 3 × 131 – 189 – 186 = 216 JK–1 mol–1 (1) the entropy change in –TS (1) makes G -ve once T is high enough (1) 6 (c) diamond  graphite S = +3 JK–1 mol–1 (1) since H  0, G is always  0 (1) kinetics: large Ea makes reaction too slow (1) 3 (d) CaO(s) + CO2(g)  CaCO3(s) S = 90 – 40 – 214 = –164 JK– mol–1 (1) G = 0, H = TS Ts = = 1085 K (1) 2 [15]
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