394kJ的精选

问题详情：已知：①C(s)＋O2(g)===CO2(g)ΔH1＝－394kJ·mol－1；②H2(g)＋O2(g)===H2O(g)ΔH2＝－242kJ·mol－1；③2C2H2(g)＋5O2(g)===4CO2(g)＋2H2O(g)ΔH3＝－2510kJ·mol－1；④2C(s)＋H2(g)===C2H2(g)ΔH4。下列说法正确的是A、反应①放出197kJ的热量...