Chapter 6, Problem 72E

Under certain nonstandard conditions, oxidatin by ${\text{O}}_2\text{(}g\text{)}$ of 1 mol of ${\text{SO}}_2\text{(}g\text{)}$ to ${\text{SO}}_3\text{(}g\text{)}$ absorbs 89.5 kJ. The heat of formation of ${\text{SO}}_3\text{(}g\text{)}$ is −204.2 kJ under these conditions. Find the heat of formation of ${\text{SO}}_2\text{(}g\text{)}$ .