氢气.一氧化碳.辛烷.甲烷!~完全燃烧时放热多少?

H2(g)＋ O2(g)＝H2O(l)；△H＝－285.8 kJ / mol CO(g)＋ O2(g)＝CO2(g)；△H＝－283.0 kJ / mol C8H18(l)＋25/2O2(g)＝8CO2(g)＋9H2O(l)；△H＝－5518 kJ / mol CH4(g)＋2O2(g)＝CO2(g)＋2H2O(l)；△H＝－89.3 kJ / mol