Berapa ∆H reaksi pembakaran 1 mol gas metana adalah

Dik : [tex]C + 2H_{2} == \ \textgreater \ CH_{4}[/tex] ΔHf = -75 kJ/Mol
        [tex]C + O_{2} ===\ \textgreater \ CO_{2} [/tex] ΔHf = -393,5 kJ/Mol
        [tex] H_{2} + \frac{1}{2} O_{2} ===\ \textgreater \ H_{2}O [/tex] ΔHf = -242 kJ/Mol
Dit : [tex] CH_{4} + 2O_{2} ===\ \textgreater \ CO_{2} + 2H_{2}O[/tex] ΔHc ?
Jawab :
[tex]CH_{4} ===\ \textgreater \ C + 2H_{2}O [/tex] ΔH = +75 kJ/Mol
[tex]C + O_{2} ===\ \textgreater \ CO_{2} [/tex] ΔH = -393,5 kJ/Mol
[tex]2H_{2}O + O_{2} ===\ \textgreater \ 2H_{2}O [/tex] ΔH = -484 kJ/Mol

Jadi, ΔHc = 75 + (-393,5) + (-484) = - 802,5 kJ/Mol