Before the proliferation of personal computers, it was often convenient to summarize thermodynamic property data in the form of graphic diagrams. The Mollier diagram presents h (y-axis)

vs. s (x-axis). Obtain an expression for the slope of an isochor (constant-volume line) on a Mollier diagram for

(a) an ideal gas (in terms of T, v, cv, cP, and R);

(b) a van der Waals gas (in terms of T, v, cv, cP,

a, b and R).