Chapter 4, Problem 4.15E

Calculate $\Delta G$ in two different ways for the dimerization of ${\text{NO}}_{\text{2}}$:

${\text{2NO}}_{\text{2}}\left(\text{g}\right)\to {\text{N}}_{\text{2}}{\text{O}}_{\text{4}}\left(\text{g}\right)$

Are the two values equal?