Entropy Change of an Ideal Gas

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Homework Statement


Using the expression for the entropy change of an ideal gas when the volume and temperature change and TV[itex]\gamma-1[/itex] = constant, show explicitly that the change in entropy is zero for a quasi-static adiabatic expansion from state V1T1 to state V2T2.


Homework Equations


TV[itex]\gamma-1[/itex] = constant

dS = dQr / T

The Attempt at a Solution



My idea was to use T1V1[itex]\gamma-1[/itex] = T2V2[itex]\gamma-1[/itex] 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?
 

Answers and Replies

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

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