## Calculating residual entropy

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

navessor
Posts: 16
Joined: Fri Sep 25, 2015 3:00 am

### Calculating residual entropy

How do you calculate which has a greater residual entropy, NO or BF3?

PaigeBlack
Posts: 32
Joined: Fri Sep 25, 2015 3:00 am

### Re: Calculating residual entropy

BF3 would have a greater residual entropy because it is a more complex molecule which allows more rotation and vibration.

Aoife Galvin 2D
Posts: 9
Joined: Fri Sep 25, 2015 3:00 am

### Re: Calculating residual entropy

I thought that BF3 would have a greater residual entropy too, but on page 176 of the course reader, winter 2011 final exam question 1C, the answer says NO would have a greater residual entropy.

Ritika Saranath 3I
Posts: 24
Joined: Fri Sep 25, 2015 3:00 am

### Re: Calculating residual entropy

NO can be oriented as both NO and ON; BF3, no matter how you rotate the molecule, will look the same, because the F's are symmetric around the B. Therefore, NO has higher residual entropy, because it takes upon more orientations.