Thomsen-Berthelot principle
A 2001 inorganic chemistry textbook summary of the the Thomson-Berthelot principle. [1]
In chemistry, the Thomsen-Berthelot principle (or Berthelot-Thomsen principle) argued that heat release or in modern speak that enthalpy was the driving force of a chemical reaction and that only exothermic reaction would occur spontaneously. The principle argued, in short, that heat is the driving force of chemical reactions and hence the measure of chemical affinity.

This principle was postulated independently in 1854 by Danish chemist Julius Thomsen and in 1864 by French chemist Marcellin Berthelot.

Another synonymous name is the principle of maximum work.

Chemical thermodynamics
The Thomsen-Berthelot principle was superseded by the "free energy principle", that free energy is the true measure of affinity, as proved in 1882 by German physicist Hermann Helmholtz, in which “On the Thermodynamics of Chemical Processes”. [2]

Absolute zero
The Thomsen-Berthelot principle was shown to only be true at absolute zero, as proved by German physical chemist Walther Nernst in his circa 1906 heat theorem.

1. 1. Wilberg, Egon, Holleman, A.F., and Viberg, Nils. (2001). Inorganic Chemistry (pg. 49). Academic Press.
2. Helmholtz, Hermann. (1882). “On the Thermodynamics of Chemical Processes”, in: Physical Memoirs Selected and Translated from Foreign Sources, 1: 43-97. Physical Society of London, Taylor and Francis, 1888.

External links
‚óŹ Thomsen-Berthelot principle – Wikipedia.

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