\(T_{f}(r e v .) < T_{f}(i r r .)\)
$CH _{4}+2 O _{2} \rightarrow CO _{2}+2 H _{2} O (\Delta H =-891 kJ / mol)$
${C_{\left( {graphite} \right)}} + {O_{2\left( g \right)}} \to C{O_{2\left( g \right)}}\,;\,\Delta H = -393.5\,kJ$
${C_2}{H_{4\left( g \right)}} + 3{O_{2\left( g \right)}} \to 2C{O_{2\left( g \right)}} + 2{H_2}{O_{\left( l \right)}}\,;\,\Delta H = - 1410.9\,kJ$
${H_{2\left( g \right)}} + 1/2{O_{2\left( g \right)}} \to {H_2}{O_{\left( l \right)}}\,;\,\Delta H = - 285.8\,kJ$
(આપેલ : $\mathrm{R}=8.3 \mathrm{JK}^{-1} \mathrm{~mol}^{-1}$ )
${H_2}{O_{(g)}} + {C_{(s)}}\, \to \,\,C{O_{(g)}} + {H_{2(g)}}\,:\,\,\Delta H\, = \,\,131$ કિલોજૂલ $C{O_{(g)}} + \,\,\frac{1}{2}\,\,{O_{2(g)}} \to \,\,C{O_{2(g)}}\,:\,\,\Delta H\,\, = \,\, - 282$ કિલોજૂલ
${H_{2(g)}} + \frac{1}{2}{O_{2(g)}} \to \,{H_2}{O_{(g)}}\,:\,\Delta H\,\, = \,\, - 242\,\,$ કિલોજૂલ
$C_{(g)} + O_2$$_{(g)}$ $\to$ $CO_2$$_{(g)}$ : $\Delta H = x$ કિલોજૂલ