Re: DW/DW Summary

[Jim Green <JMGreen@SISNA.COM>]

At 10:09 PM 01-11-99 -0500, someone  wrote:
> Vehemently NO for your 7) and 8).

Margaret!!!  Help!!! The other boys on the playground are being raucous,  I
wish there were more girls here.  They are nicer -- and better looking too.

In the light of morning,  I see that I have experienced a major mental
lapse: what I wrote in 7) and 8) is faulty,  But I don't yet see where the
error is.  I will have to think more on this and on Bob's statements below,
which, I believe, are faulty as well.  But I can't think with all this
commotion.

I _am_ pleased that points 1 through 6 (which I fervently stand behind) are
accepted -- at least in part.  This has been a several year effort! (:-)

Jim

> dQ is different for different paths between the same two states.
>
> dQ =TdS ONLY for a reversible path between the two given states.
>
> dS =dQ/T (reversible process) is path independent;
>
> dQ (even for reversible processes {where dQ=Tds} ) is path dependent.
>
> Bob
>
> > . . .
> > 7) The only way to calculate DQ for the irreversible process is to
> choose a
> > reversible process with the same end states as the irreversible one,
> > determine the end point entropy of that process and then calculate
> DQ=TdS.
> >
> > 8) In some cases dS  might be determined from a carefully chosen DQ of
> the
> > reversible process, but that would be the same DQ for the irreversible

Jim Green
mailto:JMGreen@sisna.com
http://users.sisna.com/jmgreen