## Difference between equations

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

Rita Chen 1B
Posts: 112
Joined: Sat Jul 20, 2019 12:15 am

### Difference between equations

When would I use nRln(V2/V1) and when would i use nCpln(T2/T1)? If the pressure is constant and the volume changes, the temperature changes too, so shouldn't both equations be able to be used?

Daniela Shatzki 2E
Posts: 53
Joined: Sat Aug 24, 2019 12:16 am

### Re: Difference between equations

I think generally either both pressure and temperature will be constant resulting only in a change in volume or pressure and volume would be constant resulting in only a change in temperature. If there is a change in volume use nRln(V2/V1), if there is a change in temperature use nCln(T2/T1).

Robert Tran 1B
Posts: 118
Joined: Thu Jul 11, 2019 12:15 am

### Re: Difference between equations

nRln(V2/V1) only works when the temperature is constant because it is derived from the equation (delta)S = q/T, which assumes that temperature is constant.