Persistent confusion of total entropy and chemical system entropy in chemical thermodynamics

摘要

The change in free energy with temperature at constant pressure of a chemical reaction is determined by the sum (dS) of changes in entropy of the system of reagents, dSi, and the additional entropy change of the surroundings, dS_H, that results from the enthalpy change, dH. A faulty identification of the total entropy change on reaction with dSi has been responsible for the attribution of general validity to the expressions (dΔG/dT)_P = -ΔSi and d(ΔG/T)/d(1/T) = ΔH, which are found in most textbooks and in innumerable papers.