Re: [Phys-l] how not to do thermodynamics and Legendre transformations

[Carl Mungan <mungan@usna.edu>]

> I mention this because I recently encountered the
> following article:
>   USE OF LEGENDRE TRANSFORMS IN CHEMICAL THERMODYNAMICS
>               (IUPAC Technical Report)
>             Prepared for publication by
>                 ROBERT A. ALBERTY
>
>                 Pure Appl. Chem.,
>         Vol. 73, No. 8, pp. 1349-1380, 2001.
>
> That article states, as if it were an established fact,
> that the equation
>
>       dU = TdS - PdV ...             [1]
>
> is "the" fundamental equation for the energy U. <snip>
>
> The paper goes on to assert that
>
>      "The variables in the differentials on the right-hand
>      side of the fundamental equation have a special
>      significance and are referred to as natural variables"
>
> and cites almost a dozen references.
>
> I disagree with this conclusion even more strongly than
> I disagreed with "the fundamental equation".

Interesting that you mention that paper, because a chemist friend 
recently cited that exact paper to me and told me that he was still 
confused about Legendre transforms and could I explain it to him more 
simply?

In reply I wrote:

http://usna.edu/Users/physics/mungan/Scholarship/LegendreTransform.pdf

and would glady accept your (or other folks) comments on it. -Carl
--
Carl E Mungan, Assoc Prof of Physics  410-293-6680 (O) -3729 (F)
Naval Academy Stop 9c, 572C Holloway Rd, Annapolis MD 21402-1363
mailto:mungan@usna.edu     http://usna.edu/Users/physics/mungan/