$298 \,K \,NH_3$$_{(g)}$ અને $H_2O_{(l)}$ ની નિર્માણ ઉષ્મા અનુક્રમે $-46.0$ અને $-286.0\, kJ \,mol^{-}$ છે.
${{\text{H}}_{\text{2}}}{\mkern 1mu} + {\mkern 1mu} {\mkern 1mu} \frac{{\text{1}}}{{\text{2}}}{{\text{O}}_{\text{2}}}{\mkern 1mu} \to {\mkern 1mu} {{\text{H}}_{\text{2}}}{\text{O}}{\mkern 1mu} {\mkern 1mu} \Delta {H_2}{\mkern 1mu} = {\mkern 1mu} {\mkern 1mu} {\text{ - }}{\mkern 1mu} {\mkern 1mu} {\text{286}}\,{\text{KJ}}$
$\,{\text{4N}}{{\text{H}}_{\text{3}}}\, + \,\,{\text{3}}{{\text{O}}_{\text{2}}}\, \to \,\,{\text{2}}{{\text{N}}_{\text{2}}}\, + \,\,{\text{6}}{{\text{H}}_{\text{2}}}{\text{O,}}\,\,\Delta {\text{H}}\,\, = \,\,{\text{?}}$
$\begin{gathered}
\Delta {\text{H}}{\mkern 1mu} {\mkern 1mu} = {\mkern 1mu} {\mkern 1mu} {\text{6}}\Delta {\mkern 1mu} {{\text{H}}_{\text{2}}}{\mkern 1mu} {\text{ - }}{\mkern 1mu} {\mkern 1mu} {\text{4}}{\mkern 1mu} \Delta {\mkern 1mu} {{\text{H}}_{\text{1}}}{\mkern 1mu} {\mkern 1mu} {\mkern 1mu} \hfill \\
\Rightarrow {\mkern 1mu} {\mkern 1mu} {\mkern 1mu} \Delta {\text{H}}{\mkern 1mu} {\mkern 1mu} = {\mkern 1mu} {\mkern 1mu} {\text{6( - 286)}}{\mkern 1mu} {\text{ - }}{\mkern 1mu} {\text{4}}{\mkern 1mu} {\text{( - 46)}}{\mkern 1mu} {\mkern 1mu} \hfill \\
= {\mkern 1mu} {\mkern 1mu} {\text{ - }}{\mkern 1mu} {\mkern 1mu} {\text{1716}}{\mkern 1mu} {\mkern 1mu} + {\mkern 1mu} {\mkern 1mu} {\text{184 }}{\mkern 1mu} {\mkern 1mu} \hfill \\
\therefore {\mkern 1mu} {\mkern 1mu} \Delta {\text{H}}{\mkern 1mu} {\mkern 1mu} = {\mkern 1mu} {\mkern 1mu} {\text{ - }}{\mkern 1mu} {\mkern 1mu} {\text{1532}}{\mkern 1mu} \,{\text{KJ}} \hfill \\
\end{gathered} $
$(I)\,\,q + \mathrm{w}$ $(II)\,\, q$
$(III)\,\, \mathrm{w}$ $(IV)\,\, H - TS$