7、;1molCH4完全燃烧生成液态水和CO2,放出890.3kJ的热量。下列热化学方程式的书写正确的是( B )①CH4(g)+2O2(g)===CO2(g)+2H2O(l)ΔH=+890.3kJ/mol②CH4(g)+2O2(g)===CO2(g)+2H2O(l)ΔH=-890.3kJ/mol③CH4(g)+O2(g)===CO2(g)+2H2O(g)ΔH=-890.3kJ/mol④2H2(g)+2O2(g)===2H2O(l)ΔH=-571.6kJ/molA.仅有② B.仅有②④C.仅有②③④D.全都符合要