Chapter 18, Problem 131RQ

Given the following reactions and their values of $\Delta G°$, calculate the value of $\Delta G_{\text{f}}^{\text{o}}{\text{ for N}}_{\text{2}}{\text{O}}_{\text{5}}\left(g\right)$.

$\begin{array}{l}2{\text{H}}_{\text{2}}\left(g\right)+\text{O2}\left(g\right)\to 2{\text{H}}_{\text{2}}\text{O}\left(l\right)\Delta G°=474.4\text{kJ}\\ {\text{N}}_{\text{2}}{\text{O}}_{\text{5}}\left(g\right)+{\text{H}}_{\text{2}}\text{O}\left(l\right) \to 2{\text{HNO}}_{\text{3}}\left(l\right)\Delta G°=-37.6\text{kJ}\\ \frac{1}{2}{\text{N}}_{\text{2}}\left(g\right)+\frac{3}{2}{\text{O}}_{\text{2}}\left(g\right)+2{\text{H}}_{\text{2}}\left(g\right)\to {\text{HNO}}_{\text{3}}\left(l\right)\Delta G°=-79.91\text{kJ}\end{array}$