## 8.33

Volume: $\Delta S = nR\ln \frac{V_{2}}{V_{1}}$
Temperature: $\Delta S = nC\ln \frac{T_{2}}{T_{1}}$

Jessica Jones 2B
Posts: 80
Joined: Fri Sep 29, 2017 7:04 am

### 8.33

I was under the impression that for a monoatomic gas, C= 3/2 * R, for a diatomic gas, C= 5/2 * R, and for a polyatomic gas, C= 7/2 * R, but in the solution manual polyatomic is 3* R. Could someone explain this?

Britney Alvey 1B
Posts: 31
Joined: Fri Jun 23, 2017 11:39 am

### Re: 8.33

The question asks for Cv. The Cv vaule for polyatomic gases is 3*R. The value 7/2*R is the Cp value for diatomic molecules. You can reference the table on page 281 in the book which lists the Cv and Cp values for ideal gases.