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its intrinsic entropy S i , and partly potential, determined by H, the energy locked in the bonds that partake in the chemical reaction.
Contrary to W's first sentence, the most remarkable thing about this beginning is how very unfamiliar it is. Nowhere else does one find such eccentric terminology or so many conceptual puzzles. Let me count the ways: (1) What could be meant by the phrase: ''free energy associated to each reagent''? (2) Almost all authors now use G to refer to the free energy of an entire thermodynamic system or phase. Since W is principally concerned with chemical reactions in liquid solution, I confine attention to that case to focus our ideas. Normally, then, G would mean the Gibbs energy of the entire solution, not that ''associated to each reagent.'' Moreover, what accounts for the lone subscript in an equation that would otherwise at least look familiar? (3) The term ''heat content'' is antiquated and has not been used in decades for very good reason. Heat is not a state function, so a body cannot be said to ''contain'' a given amount of it. The term is an historical holdover from the old caloric theory, in which heat is held to be a fluid. The term sometimes appears in competent thermodynamic texts dating from the first half of this century, but only as a synonym for enthalpy. Never is it encountered as meaning Gibbs energy. (4) No competent thermodynamic textbook talks of an ''intrinsic entropy,'' whatever that may mean, or contrasts an ''actual'' vs a ''potential'' heat.
The puzzling phrases ''free energy associated to each reagent'' in the cited passage and ''chemical system entropy'' (as contrasted with ''total entropy'') in the title of W suggest that W wishes to decompose the thermodynamic properties of the solution into contributions from the various reaction-participant solutes contained therein.