The latent heat of formation of \(\mathrm{H}_{2} \mathrm{O}(\mathrm{g})=-5800 \mathrm{cal}\) at \(500 \mathrm{~K}\). What will be the heat of formation at \(1000 \mathrm{~K}\) ? We are given that

\[ \begin{aligned} C_{P_{\mathrm{H}_{2}}} & =6.94-0.2 \times 10^{-3} T \\ C_{P_{\mathrm{O}_{2}}} & =6.15+3.2 \times 10^{-3} T \\ C P_{\mathrm{H}_{2} \mathrm{O}} & =7.25+2.28 \times 10^{-3} T \end{aligned} \]