Chapter 6, Problem 26PE

Write thermochemical equations corresponding to $\Delta H_{\text{f}}{}^{\text{°}}$ for $S{O}_3\left(g\right)$ and ${\text{SO}}_{\text{2}}\left(g\right)$ and show how they can be manipulated to calculate $\Delta H°$ for the following reaction:

${\text{SO}}_{\text{3}}\left(g\right)\to {\text{SO}}_{\text{2}}\left(g\right)+\frac{1}{2}{\text{O}}_{\text{2}}\left(g\right)\Delta H°=?$?

Use liquation 6.14 to calculate $\Delta H°$ for the reaction using the heats of formation of ${\text{SO}}_{\text{3}}(g){\text{ and SO}}_{\text{2}}(g)$. How do the answers compare?