已知:①C(s)+O2(g)=CO(g) ΔH1=-110.5kJ·mol−1;
②H2(g)+O2(g)=H2O(g) ΔH2=-241.8kJ·mol−1;
③C(s)+O2(g)=CO2(g) ΔH3=-393.5kJ·mol−1;