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Re: [Phys-l] polytropic Sackur-Tetrode

On 01/20/2010 10:48 AM, Carl Mungan wrote:

On page 255 he discusses this kind of thing, but
in addition to the electronic "weight" (partition
function), he points out you need to include a
rotational partition function.....

1) Hmmm, clearly my first attempt to derive the entropy
of a polytropic gas was not correct.

2) I would hope that if the gas is really polytropic,
the "weight" factor and everything else could be
deduced from the observed gamma. I'm hoping that
only one new variable (gamma) needs to appear on
the RHS of the Sackur-Tetrode equation (as opposed
to gamma, weight, and who-knows-what else).

Or maybe I'm wrong about that, too. Is it really
possible to have two different polytropic gases
with the same gamma but different entropy ... and
therefore different heat capacity? Doesn't that
conflict with the notion of gamma as the ratio of
specific heats? I gotta go do the math on this