Calculating residual entropy

[navessor]

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

[PaigeBlack]

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

[Aoife Galvin 2D]

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]

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.