## Change of Entropy for V and T

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

Melodie Oh 2A
Posts: 22
Joined: Fri Sep 29, 2017 7:06 am

### Change of Entropy for V and T

Why does the equation of entropy change for change in volume use V2/V1 while it is P1/P2 for the change in pressure?

Audrey Goodman 1F
Posts: 31
Joined: Fri Sep 29, 2017 7:06 am

### Re: Change of Entropy for V and T

If you consider the equation PV=nRT, you can see that pressure (P) and volume (V) are inversely proportional. Because they are inversely proportional, when you substitute P for V, the ratio is switched.

Wayland Leung
Posts: 51
Joined: Sat Jul 22, 2017 3:00 am
Been upvoted: 1 time

### Re: Change of Entropy for V and T

In the ideal gas law, pressure is the inverse of volume so you flip the pressure values in order to find the change in entropy.