## Heat Capacity when cooling

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

YashDeshmukh1D
Posts: 42
Joined: Fri Sep 29, 2017 7:05 am

### Heat Capacity when cooling

In Example 9.6 in the textbook, it uses the given heat capacity when measuring the entropy change from heating the liquid. However, when calculating entropy change for cooling the vapor back down, it uses Cp,m, which multiplies the given heat capacity by 4. When do you use each one?

David Minasyan 1C
Posts: 54
Joined: Thu Jul 13, 2017 3:00 am

### Re: Heat Capacity when cooling

I'm pretty sure you're just supposed to use the C value that corresponds to the phase of the reactant. So if it's a liquid, use the regular C value at 4.184, or if its solid then use that one and the same with vapor.