CO(g)

C(s)

CO2(g)

△H1 = △H2 + △H3

∴△H3 = △H1 － △H2 = -393.5 kJ/mol －(-283.0 kJ/mol) = -110.5 kJ/mol

① C(g) + O2 (g) = CO2 (g) △H1 =- 393.5kJ /mol

② CO(g) + 1/2O2 (g) = CO2 (g) △H2 =- 283.0 kJ /mol

C(s) + ½ O2(g) = CO(g) △H3=？