Calcium carbonate (3) has two polymorphs, calcite and aragonite. The volume chan
ID: 1054630 • Letter: C
Question
Calcium carbonate (3) has two polymorphs, calcite and aragonite. The volume change for the calcite to aragonite transformation is 2.7843/ and is assumed to be independent of temperature and pressure. The chemical potential change for the calcite to aragonite transformation as a function of temperature at 1 is given by Chemical potential (mu) = 210 + 4.2T (J/Mol).
Determine whether an increase in pressure at a fixed temperature will increase or decrease the thermodynamic stability of aragonite with respect to calcite.
Explanation / Answer
The theromodynamic stability will depend upon the chemical potential. Here in this case change in the chemical potential for the transformation of calcite to aragonite get decreased with increase in pressure.
This shows that the stability of calcite at higher pressure is more than aragonite.