${S_R} + {O_{2\left( g \right)}} \to S{O_{2\left( g \right)}};\,\Delta H = - 296.90\,kJ$
${S_M} + {O_{2\left( g \right)}} \to S{O_{2\left( g \right)}};\,\Delta H = - 299.40\,kJ$
\(ii)\) \(S _{ M }+ O _2 \longrightarrow SO _2 \quad \Delta _{ ii }=-299.4\)
\(iii)\) \(S_R \longrightarrow S_M\)
\(\therefore \Delta H=\Delta H_i-\Delta H_{i i }=-296.9-(-299.4)=2.5\,kJ\)
($\Delta H$ અને $\Delta S$ તાપમાન સાથે બદલાતા નથી તેમ ધારો)
[ઉપયોગ : $\left.{R}=8.3 \,{~J} \,{~mol}^{-1}\, {~K}^{-1}\right]$