Archived Entropy Change of an Ideal Gas

1. Sep 16, 2012

mouzis

1. The problem statement, all variables and given/known data
Using the expression for the entropy change of an ideal gas when the volume and temperature change and TV$\gamma-1$ = constant, show explicitly that the change in entropy is zero for a quasi-static adiabatic expansion from state V1T1 to state V2T2.

2. Relevant equations
TV$\gamma-1$ = constant

dS = dQr / T
3. The attempt at a solution

My idea was to use T1V1$\gamma-1$ = T2V2$\gamma-1$ and solve for T in terms of V and substitute in to the second equation. I couldn't figure it out from there, so my question is is my idea of what to do fundamentally wrong, or is my calculation once i set up the problem wrong?

2. Mar 14, 2016

Staff: Mentor

$$dS=C_v\frac{dT}{T}+R\frac{dV}{V}$$