All Problems

Second law of thermodynamics, entropy

Problem 2.141

One mole of a Van der Waals gas which had initially the volume \(V_{1}\) and the temperature \(T_{1}\) was transferred to the state with the volume \(V_{2}\) and the temperature \(T_{2}\). Find the corresponding entropy increment of the gas, assuming its molar heat capacity \(C_{V}\) to be known.

Reveal Answer
ΔS=CVln⁡(T22/T1)+Rln⁡[(V2−b)/(V1−b)]\Delta S=C_{V} \ln \left(T_{2}^{2} / T_{1}\right)+R \ln \left[\left(V_{2}-b\right) /\left(V_{1}-b\right)\right]