Schottky, Ulich and Wagner

In all instances where experiments have been carried out, this inequality has been verified (cf. Van Rysselberghe, loc. cit.). 

We may stress at this point that the conception of the role played by irreversible processes developed here is quite different from that in classical thermodynamics. In the latter, irreversible changes appear only as undesirable effects which reduce the efficiency of heat engines and which one must attempt to eliminate. On the other hand thermodynamic coupling, enables us to predict results such as separations and syntheses, which would be quite impossible to derive in the absence of a consideration of irreversible changes. 

Thermodynamic coupling has, of course, no infiuence on equilibria, since for true equilibrium all the reaction velocities are zero and 

Comparison with the method of Schottky, Ulich and Wagner. 

The thermodynamic method developed in this work is analogous in several ways to that of Schottky, Ulich and Wagner [42]. Both have the same aim to develop a consistent thermodynamic treatment of chemical reactions. They both place the main emphasis upon the chemical reaction, whereas in Gibbs work the stress is laid on the components of a system and their chemical potentials. Both begin from the same point the recognition of the essential fact that, except for the special limiting case of equilibrium reactions, chemical reactions are all irreversible phenomena, and both discuss the way in which this irreversibility manifests itself. 

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THE. 15. R. Defay et I. Prigogine, Methode thermodynamique de Th. De Donder et methode thermodynamique de Schottky, Ulich et Wagner (Thermodynamic method of Th. De Donder and thermodynamic method of Schottky, Ulich and Wagner), Bull. Cl. Sci. Acad. Roy. Belg. 33, 222-232... 

Duhem-Margules equation for compounds with a small deviation from the stoichiometric composition [ Schottky, Ulich, and Wagner, Thermodynamik, p. 375, Berlin 1929), the sum of the chemical potentials of anions and cations is constant in the crystal (and in its surface), (d) In the steady state of the dissolution process, equivalent numbers of anions and cations have to pass through the phase boundary per unit time. 

The loss of work is thus simply equal to the uncompensated heat, and we obtain De Lender s fundamental inequality. Schottky, Ulich and Wagner s method thus leads to the same results as ours, but requires the association of a hypothetical reversible process with each real irreversible change. 

The method developed here is in many ways analogous to that employed by Schottky, Ulich and Wagner. Both methods emphasize the criterion for establishing the irreversibility of a chemical reaction and for deciding whether the reaction will proceed spontaneously in a particular direction. In De Bonder s method this criterion appears immediately the production of entropy must be positive. On the other hand Schottky, Ulich and Wagner employ as the criterion of irreversibility the loss of useful work associated with the real process when compared with a hypothetical reversible process. As is shown in chap. V, these criteria are equivalent for isothermal changes. For non-isothermal changes, however, the concept of loss of useful work... 

Refs. [i] Schottky W (1928) Physik der Gluhelektroden. Akademische Verlagsgesellschaft, Leipzig [ii] Johnson JB (1971) IEEE Spectrum 8 42 [iii] Schottky W, Ulich H, Wagner C (1929) Thermodynamik. Springer Berlin [iv] Sharma BL (ed) (1984) Metal-semiconductor Schottky barrier functions and their applications. Springer New York... 

W.Schottky, H. Ulich and C. Wagner, Thermodynamik, VDI Buckhandlung, Berlin, 1929. V Innere Energie w Gibbsache W xme-funktion F Fieie Energie G Gihbssche thermody-namisches Potential ... 

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