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Time Variation of Chemical Affinity


IN two previous communications1,2 we have shown that an accelerated chemical reaction is always characterized by the variation of the chemical affinity of the system with time. For a reaction with constant velocity this time derivative would, of course, be zero. In this communication we shall consider further the properties of the function &Adot;≡(dA/dt. A is the instantaneous chemical affinity defined by In this equation, ν i is the stoichiometric coefficient, and µi is the instantaneous chemical potential of the ith component. Since this potential is a function of the activity of the particular substance, it will vary with concentration, and hence with time. Bearing this in mind, we can now differentiate equation (1) with respect to time: Throughout this discussion the pressure and temperature will be assumed constant.

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  1. 1

    Raw, C. J. G., and Yourgrau, W., Nature, 178, 809 (1956).

  2. 2

    Yourgrau, W., and Raw, C. J. G., Nuovo Cimento, 5, Supp. 3, 472 (1957).

  3. 3

    Prigogine, I., and Defay, R., “Chemical Thermodynamics” (Longmans, Green and Co., London, 1954).

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