Consider a real gas, which obeys the following equation-of-state:
$$v=\dfrac{R T}{P}+C_{1}-\dfrac{C_{2}}{P v},$$
where $v$ is the mass specific volume, $P$ is the pressure, $T$ is the temperature and $R$ is the gas constant. $C_{1}$ and $C_{2}$ are constants. If $s$ is the mass specific entropy, the quantity $\left(\dfrac{\partial s}{\partial v}\right)_{T}$ for the gas is given by
- $\dfrac{R}{v}$
- $\dfrac{R^{2} T}{P v^{2}}$
- $\dfrac{R}{v-C_{1}}$
- $\dfrac{C_{1} C_{2}}{T v}$
