(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

I'm asked to compute the molar entropy of oxygen gas @ 298.15 K & 1 bar given:

molecular mass of 5.312×10−26 kg, Θvib = 2256 K, Θrot = 2.07 K, σ = 2, and ge1 = 3. I'm currently stuck on the vibrational entropy calculation.

2. Relevant equationsS = NkT ∂/∂T {ln q} + Nk ln (q/N) + Nk

where N is Avogadro's # & k is Boltzman's constant,

so Nk = R.

qvib = e-(Θvib/2T)/(1 - e-(Θvib/T)) where Θvib = hν/k

3. The attempt at a solution

For the derivative of ln q

I get

∂/∂T {ln q} = Θvib/2T^2{[1+ e-(Θvib/T)]/[1 - e-(Θvib/T)] which @ Θvib = 2256 K is(?) Θvib/2T^2,

so for the first part of the entropy calculation I would have a contribution of

RΘvib/2T.

I can plug in the numbers but I just want to know if I'm headed in the correct direction with this and I will return to confirm other parts of the calculation.

**Physics Forums | Science Articles, Homework Help, Discussion**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Vibrational entropy and the partition function

Tags:

Have something to add?

**Physics Forums | Science Articles, Homework Help, Discussion**