$\begin{gathered}
(W)\,\, = \,\, - \,P({V_2}\, - \,\,{V_1})\,\,\, \Rightarrow \,\,W\,\, = \,\, - \,3\,\, \times \,\,(5\,\,\, - \,\,3)\,\, = \,\, - 3\,\, \times \,\,2\,\,litre\,\,atm\, \hfill \\
= \,\, - \,\frac{{6\,\, \times \,\,4.184\,\, \times \,1.987}}{{0.0821}}\,\,joule\,\, = \,\, - 607.8\,joule \hfill \\
\end{gathered} $
હવે, આ કાર્યનો ઉપયોગ પાણીને ગરમ કરવા થાય છે
$W = $ $q_p$ $ = 607.8\, joule$ ∵ $q_p$ = $mC_P$$\Delta T$
$607.8 = 10 × 18 × 4.184 ×$ $\Delta T$
$\Delta T = 0.80 → \Delta T = T_2 - T_1 → 0.80 = T_2 - 290 → T_2$
$= 290 + 0.80 = 290.80 \,K $
${H_2}{O_{(g)}} + {C_{(s)}}\, \to \,\,C{O_{(g)}} + {H_{2(g)}}\,:\,\,\Delta H\, = \,\,131$ કિલોજૂલ $C{O_{(g)}} + \,\,\frac{1}{2}\,\,{O_{2(g)}} \to \,\,C{O_{2(g)}}\,:\,\,\Delta H\,\, = \,\, - 282$ કિલોજૂલ
${H_{2(g)}} + \frac{1}{2}{O_{2(g)}} \to \,{H_2}{O_{(g)}}\,:\,\Delta H\,\, = \,\, - 242\,\,$ કિલોજૂલ
$C_{(g)} + O_2$$_{(g)}$ $\to$ $CO_2$$_{(g)}$ : $\Delta H = x$ કિલોજૂલ