Question

The equation of state in the given range of pressure and temperature is given by

v = \(\cfrac{RT}p\) - \(\cfrac{C}{T^3}\)

where C is constant. 

Derive an expression for change of enthalpy and entropy for this substance during an isothermal process.

Answer 1

The general equation for finding dh is given by

as dT = 0 for isothermal change. 

From the given equation of state, we have

The general equation for finding ds is given by

as dT = 0 for isothermal change. 

Substituting the value from eqn. (i), we get