When to use deltaS=q/t versus deltaS=nRlnV2/V1

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

Josephine Lu 4L
Posts: 62
Joined: Fri Sep 28, 2018 12:18 am

When to use deltaS=q/t versus deltaS=nRlnV2/V1

In what circumstances should I use the equation of change in entropy deltaS=q/t versus deltaS=nRlnV2/V1? I don’t know when I should use which equation.

Hanniel U 2B
Posts: 76
Joined: Fri Sep 28, 2018 12:16 am

Re: When to use deltaS=q/t versus deltaS=nRlnV2/V1

Use deltaS= nRLnV2/V1 when there is a change in entropy of an ideal gas when there is an isothermal expansion from a volume V1 to V2. Use deltaS= q/t when you are trying to find the change in entropy with given heat energy and temp.

RachelCheung1A
Posts: 30
Joined: Fri Sep 28, 2018 12:19 am

Re: When to use deltaS=q/t versus deltaS=nRlnV2/V1

Use deltaS=q/t when q (heat transferred) and temperature is given. Use deltaS=nRlnV2/V1 when moles and volume change is given.