Berthelot principle

Thermochemistry, 254, 507 Thermodynamic potentials, 99 Thermo-electric circuit, 450 inversion, 451 theories, 453 Thermometers, 3, 140, 166 Thermometry, 1, 353 Thomsen-Berthelot principle, 257, 506... 

Drozin, N.N., Application of the Berthelot principle in the calculation of the standard entropies of solid inorganic compounds. Russ. J. Phys. Chem., 35, 879-881 (1961). 

Further developments with this model were to a large extent initiated by Fowkes ), who started from the assumption that the molecular forces, determining Y could be split up into components, of which only the London-van der Waals or dispersion forces had enough range to penetrate into an adjoining phase. For these forces the Berthelot principle would hold, so in (2.11.16] the geometric mean only involves the dispersion contributions to y and he replaced [2.11.17] by... 

The lack of the validity of the Thomsen-Berthelot principle is shown when one applies thermodynamics to chemical problems Horstman, 1869 (Ostwald s Klosstker), was the first to show the way of applying these thermodynamical principles A few years later Lord Rayleigh (Pros Roy Inst, 7, 386, 1875) questioned... 

It is interesting to note that the heat evolved m the reaction is small, viz 2800 calones approx It is an example of where the Berthelot principle breaks down... 

The hydrogen-oxygen or Knall-gas cell, as it is often called, offers a very striking lllustiation of the inapplicability of the Berthelot principle of considering heat as the measure of affinity Thus m the case of the cell,... 

Berthelot, Marcellin (or Marcelin) Pierre Eugene (1827-1907) French chemist and politician noted for the Thomsen-Berthelot principle of thermochemistry he synthesized many organic compounds from inorganic substances and disproved the theory of vitalism. 

As is usually the case when theoretical and experimental science meet, it is necessary to make some simplifying assumptions in order to apply theories to practical systems. Good and Girifalco proposed an empirical approach to the problem based on the Berthelot principle that the interaction constant between two different surfaces or particles will be the geometric mean of the interaction constant for the individual surface units, an approach already introduced in Chapter 4. Good and Girifalco suggested that the work of adhesion between two different liquids could be expressed as a similar function... 

The Thomsen-Berthelot principle was criticised by Rathke and by Potilit-zin. Potilitzin found that on heating a metallic chloride MCl, with bromine in a sealed tube a reaction occurs with absorption of heat, and with an equivalent n of bromine the percentage conversion to bromide is. mln y where m is the atomic weight of the metal. He also examined the action of dry hydrogen chloride on bromides. 

Van t Hoff then deals with chemical equilibrium on the basis of the law of mass action, and the change of equilibrium constant with temperature, introducing the case of condensed systems in the absence of vapour and a transition point (point de transition). Physical equilibria are special cases of chemical equilibria. Graphical methods with vapour pressure curves (e.g. for the allotropic forms of sulphur) are introduced. The principle of mobile equilibrium is explained for homogeneous and heterogeneous equilibria, and the Thomsen-Berthelot principle criticised (see pp. 614, 620). The last chapter, on affinity ,gives the definition The work of affinity (A) is equal to the heat produced in the transformation (q), divided by the absolute temperature of the transition point (P) and multiplied by the difference between this and the given temperature (P) ... 

Equation (16.9) forms the basis of the Berthelot principle [17-18] which states that dispersion interactions between dissimilar molecules can be estimated as the geometric mean of the interactions between like molecules. 

Good and Girifalco [10, 11] proposed a more empirical approach to the problem of calculating the surface and interfacial tension. The interaction constant for two different particles was assumed to be equal to the geometric mean of the interaction constants for the individual particles. This is referred to as the Berthelot principle. 

Thermochonistry — The Thomsen-Berthelot Principle — Free Energy — Dissociation — Equilibrium and Heat of Reaction — The Nemst Heat Theorem — Dixon — Influence of Moisture on Chemical Changes — The Burning of Carbon Monoxide — The Combustion of Hydrocarbons — Luminosity of Flames — The Detonation Wave — Nemst—Haber. 

Thomaon-Berthelot principle phys chem The assumption that the heat released in a chemical reaction is directly related to the chemical affinity, and that, in the absence of the application of external energy, that chemical reaction which releases the greatest heat is favored over others the principle is in general incorrect, but applies in certain special cases. tam san ber ta Io, prin sa pal) thoria See thorium dioxide. th6r-5 a ... 

The change of Gibbs energy during adhesion between two phases is the macroscopic outcome of interactions between the microscopic constituents of the different phases. According to the empirical Berthelot principle [21], the London energy of attraction between two dissimilar macrobodies is a geometric mean of the mutual interactions between similar objects, so that... 

Solid-Liquid interfacial enthalpy (Berthelot principle) ... 

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