Comments by fhe Texfbook Errors Editor
The point made in thc paper by Rasiel and Frceman was also expressed to me in a let,tcr by D. V. Fenby, Department of Chemistry, Universit,y of Otago, Duncdin, New Zcnland. I n addition, Fenby points out the necessity for a careful statement of the slandard state of real gases. He writes Fugaeiiy, f, e m he defined hy i,he relations
+
where
S is t,he molar entropy.
Therefore
At the pressure P1
M(T,P) = #"(T) RT In f
These relations imply that the standard stale is the hgpothet,ieal perfect gas a t a pl.essllre of 1 aim. At the presswe I" corresponding to unit. fugacit,y P
(T,PL) = P' (TI
However, it is fnllneio~~s to conchde from this fact that the standard state is the real gas a t a fugnciiy of I at,m. This can readily be seen in the following
The entire problem, including implications for other thermodynamic functions, is treatcd with precision by Lewis, Randall, Pitzer and Brewer on pp. 234-5 of reference given i n footnote 1,of the paper, and in "Chemical Thermodynamics" by F. D. ROSSINI,p. 242, et seq. Also of intereqt is a review by E. A. GUGGENHEIM in T~ansaetzonsqf the Faladay Society, 50,768 (1954).
Volume
46, Number 5, Moy 1969
/
31 1
