## Pressure's effect on Entropy

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

rachelmackenzie3H
Posts: 10
Joined: Fri Jul 22, 2016 3:00 am

### Pressure's effect on Entropy

How does a change in pressure affect the entropy of a gas? Does it just depend on how the pressure change affects the volume and/or temperature?

Jessica_Kim_3I
Posts: 12
Joined: Sat Jul 09, 2016 3:00 am

### Re: Pressure's effect on Entropy

Yes, I think it depends on whether the pressure (P), temperature (T), and volume (V) change and/or remain constant.
For example in a closed system (gases are ideal), if P increases and T=constant, you know that Volume must decrease. If V decreases then there is less space to explore and Entropy decreases. If P decreases, V has increased, and entropy has increased at constant T.
If T is not constant but V is constant, then increasing Temperature increases entropy since there is more thermal Energy.
If V and T are both changing, it depends. For example, if V and T increase (P decrease), there is greater entropy.

(I hope that helps! Please feel free to correct me if I said anything incorrect)