Chapter 10, Problem 53E

As ${\text{O}}_{\text{2}}\text{(}l\text{)}$ is cooled at 1 atm, it freezes at 54.5 K to formsolid I. At a lower temperature, solid I rearranges tosolid II, which has a different crystal structure. Thermalmeasurements show that $\Delta H$ for the $\text{I}\to \text{II}$ phasetransition is -743.1 J/mol, and $\Delta S$ for the same transitionis $\text{-17}{\text{.0 J K}}^{\text{-1}}{\text{mol}}^{\text{-1}}$ . At what temperature aresolids I and II in equilibrium?