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Re: [Phys-l] Temp & Energy density



Hi all-
Let me try again:
There is a thermodynamics of few-particle systems, recognized, apparently, by chemists. Instead of letting the particle number grow without bound, one considerslarge assemblages of few-particle systems.
See Hill, T., J. of Chem. Phys. 36 (1962) 3182 and textbooks by the same author. One then considers averages over the assemblge.
Regards,
Jack
"Trust me. I have a lot of experience at this."
General Custer's unremembered message to his men,
just before leading them into the Little Big Horn Valley




On Tue, 4 Aug 2009, Brian Whatcott wrote:

Donald Smith wrote:
Greetings,

Isn't the volume in question the volume occupied by the gas, not the volume of
the chamber? As others have said, by having just a few molecules, you're not in
a thermodynamic situation any more, and these two concepts are no longer the
same thing. By moving the piston when no molecules are hitting it, you are not
changing the volume of space occupied by the gas. Ultimately, I agree with the
other posters -- you're applying macroscopic concepts like pressure, temperature
and volume to a system where they don't apply. Hence, the paradoxes.

Yours,

It will not be the first time that people have tortured themselves with
conditions
that seem almost plausible... but how long would a piston take to move as
specified without touching a molecule if just ONE molecule were
contained in
a container of dimensions ~ 0.1 meter at room temperature?
If one could not move quite that fast, how much kinetic energy
would be gained by just one collision with a piston?
Would you count this as a static or equilibrium collision??

Brian W
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