Chapter 6, Problem 6.23E

Sulfur, in its cyclic molecular form having the formula ${\text{S}}_{\text{8}}$, is an unusual element in that the solid form has two easily accessible solid phases. The rhombic crystal solid is stable at temperatures lower than $95.\text{5}°\text{C}$, and has a density of $2.{\text{07 g/cm}}^{\text{3}}$. The monoclinic phase, stable at temperatures higher than $95.\text{5}°\text{C}$ and less than the melting point of sulfur, has a density of $\text{1}{\text{.96 g/cm}}^{\text{3}}$. Use equation 6.10 to estimate the pressure necessary to make rhombic sulfur the stable phase at $\text{100}°\text{C}$ if the entropy of transition is $1.0\text{0 J/mol}\cdot \text{K}$. Assume that ${\Delta }_{\text{trans}}S$ does not change with changing conditions.