Chapter 5, Problem 5.15E

Consider the reaction

${\text{2NO}}_2(\text{g})\rightleftharpoons {\text{N}}_{\text{2}}{\text{O}}_{\text{4}}(\text{g})$

If the partial pressures are such that $\Delta G=0.00\text{kJ}$ at $298\text{K}$, what is $p_{{\text{NO}}_2}$ if $p_{{\text{N}}_2{\text{O}}_4}=0.077\text{atm}$?