Chapter 16, Problem 35E

Given:

${\text{P}}_4\left(s\right)+5{\text{O}}_2\left(g\right)\to {\text{P}}_4{\text{O}}_{10}\left(s\right)$ $\Delta G{°}_{298}=-2697.0\text{kJ}/\text{mol}$

$2{\text{H}}_2\left(g\right)+{\text{O}}_2\left(g\right)\to 2{\text{H}}_2\text{O}\left(g\right)$ $\Delta G{°}_{298}=-457.18\text{kJ}/\text{mol}$

$6{\text{H}}_2\text{O}\left(g\right)+{\text{P}}_4{\text{O}}_{10}\left(s\right)\to 4{\text{H}}_3{\text{PO}}_4\left(l\right)$ $\Delta G{°}_{298}=-428.66\text{kJ}/\text{mol}$

(a) Determine the standard free energy of formation, $\Delta G_{\text{f}}^{°}$, for phosphoric acid.

(b) How does your calculated result compare to the value in Appendix G? Explain.