## Textbook 9.7

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

Alyssa Pelak 1J
Posts: 72
Joined: Fri Sep 29, 2017 7:04 am
Been upvoted: 1 time

### Textbook 9.7

Assuming that the heat capacity of an ideal gas is independent of temperature, calculate the entropy change associated with raising the temperature of 1.00 mol of ideal gas atoms reversibly from 37.6 C to 157.9 C at (a) constant pressure and (b) constant volume.

Can someone please explain why each equation is used for the problems?

Humza_Khan_2J
Posts: 56
Joined: Thu Jul 13, 2017 3:00 am

### Re: Textbook 9.7

For each problem, you would need to use nC(for constant pressure or volume)*ln(T2/T1). The only thing that would change is if you use the molar heat capacity for constant volume or for constant pressure. We utilize this because the process occurs with a temperature change(check the textbook for the derivation of the formula).

Renee Delamater 2H
Posts: 31
Joined: Wed Nov 16, 2016 3:02 am

### Re: Textbook 9.7

For constant pressure, you use 5/2R in the equation and for constant volume, you use 3/2R.