$\Delta U = w$
$1 \times 20 \times\left[ T _2-300\right]=-3000$
$T _2-300=-150$
$T _2=150\,K$
(ઉપયોગ કરો : $\Delta_{{c}} {H}($ ગ્લુકોઝ $)=-2700\, {~kJ}\, {~mol}^{-1}$ )
$N{H_{3(g)}}\, + \,\,\frac{3}{2}\,Cu{O_{(s)}}\, \to \,\,\frac{1}{2}\,{N_{2(g)}}\, + \,\,\frac{3}{2}{H_2}{O_{(\ell )}}\, + \,\,\frac{3}{2}\,C{u_{(s)}}.$ ......$J$