$(i)$ $NH_3$ $_{(g)} + aq$ $\rightarrow$ $NH_3$ $_{(aq)}$, $\Delta H$ $= -8.4 \,Kcal.$
$(ii)$ $HCl_{(g)} + aq$ $\rightarrow$ $HCl{(aq)}$, $\Delta H =$ ${-1}7.3\, Kcal.$
$(iii)$ $NH_3$ $_{(aq)} + HCl_{(aq)}$ $\rightarrow$ $NH_4Cl $ $_{(aq)}$, $\Delta H = -12.5\, Kcal$.
$(iv)$ $NH_4Cl$ $_{(s)} + aq$ $\rightarrow$ $NH_4Cl$ $_{(aq)}$, $\Delta H = +3.9 \,Kcal.$
$C_6H_{12}O_6 + 6O_2 \rightarrow 6CO_2 + 6H_2O ; \Delta H = -2900 \,KJ/mole $
$298 \,K \,NH_3$$_{(g)}$ અને $H_2O_{(l)}$ ની નિર્માણ ઉષ્મા અનુક્રમે $-46.0$ અને $-286.0\, kJ \,mol^{-}$ છે.