Chapter 5.3, Problem 40P

The methods of this section can also be applied to reactions in which one set of solids converts to another. A geologically important example is the transformation of albite into jadeite + quartz: ${\text{NaAlSiO}}_{\text{8}}\leftrightarrow {\text{NaAlSi}}_{\text{2}}{\text{O}}_{\text{6}}+{\text{SiO}}_{\text{2}}$.

Use the data at the back of this book to determine the temperatures and pressures under which a combination of jadeite and quartz is more stable than albite. Sketch the phase diagram of this system. For simplicity, neglect the temperate and pressure dependence of both $△S$ and $△V$.