- #1

jbowers9

- 89

- 1

## Homework Statement

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.

## Homework Equations

[/B]S = 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

## 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.