2(g)+l/2O2(g)→>H2O(g) Hm°(29815)=-241.82 K.mol-→△n C(s)+O2(g)→>CO2(g)△Hm。(g,CO2)-393.5 2H2(g)+O2(g)>2H2O(g) AHm°(298.15)=48364 KJmol-1 H2(g)+1/202(g)→>2H2O(l) AHn(298.15)=28583 kJ.mol-lH2 (g)+1/2 O2(g) → H2O (g) Hm  (298.15)=-241.82 KJ.mol-1→ fHm  C (s)+O2(g) → CO2 (g) fHm  (g,CO2)=-393.5 2H2 (g) +O2(g)→ 2H2O (g) Hm  (298.15)=-483.64 kJ.mol-1 H2 (g) +1/2O2(g)→ 2H2O (l) fHm  (l,298.15)=-285.83 kJ.mol-1