The reaction ${\mathrm{NH}}_4\mathrm{CN}\left(\mathrm{s}\right)+\frac{3}{2}{\mathrm{O}}_2\left(\mathrm{g}\right)\to {\mathrm{N}}_2\left(\mathrm{g}\right)+{\mathrm{CO}}_2\left(\mathrm{g}\right)+{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)$ was carried out in a bomb calorimeter. The heat released was $743 \mathrm{kJ} {\mathrm{mol}}^{-1}$. The value of $\mathrm{\Delta }{H}_{300\mathrm{K}}$ for this reaction would be