已知热化学方程式: ① C2H2(g) + 5/2O2(g) == 2CO2(g)+H2O(l) ΔH1=-1301.0 kJ·mol-1 ② C(s)+ O2(g) == CO2(g) △H2=-393.5 kJ·mol-1 ③ H2(g)+ 1/2O2(g) == H2O(1) △H3 = -285.8 kJ·mol-1 则反应④ 2C(s)+ H2(g) == C2H2(g)的△H为 |
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A. +228.2 kJ·mol-1 B. -228.2 kJ·mol-1 C. +1301.0 kJ·mol-1 D. +621.7 kJ·mol-1 |