2、CH4完全燃烧生成CO2和水时,放出445kJ热量,则下列热化学方程式中正确的是()A.2CH4(g)+4O2(g)=2CO2(g)+4H2O(g)ΔH=+890kJ·mol-B.CH4(g)+2O2(g)=CO2(g)+2H2O(g)ΔH=+445kJ·mol-C.CH4(g)+2O2(g)=CO2(g)+2H2O(l)ΔH=-890kJ·mol-D.2CH4(g)+4O2(g)=2CO2(g)+4H2O(l)ΔH=-890kJ·mol-3.已知反应:①101kPa时,2C(s)+O2(g)==2CO(g);ΔH=-221kJ/mol ②