Infinite copy model

We can define the left side of Equation 10.20 as AG, where the process described is one mole of reaction at constant chemical potential for reactants and products, that is, for a system large enough so that one mole of reaction can take place in the mixture without any significant change in composition or chemical potential, an infinite-copy model. As AG is a constant at constant temperature, the quantity in brackets is also a constant at constant temperamre, and, in particular, independent of the total pressure and the initial composition of the system. We therefore designate the quantity in brackets as Kp, which is the equilibrium constant in terms of partial pressures for a... 

If we assume that the solutions are of large enough volume that the transfer does not change the compositions and chemical potentials, that is the infinite copy model, then the integral in Equation (11.24) can be evaluated and... 

Equation (16.23) is a general relationship for the calculation of AGm for any reaction from the value for AGm and from the activities Oa. b. and aq. We emphasize that Equation (16.23) refers to a system in which a mole of reaction occurs with no change in the activity of any reactant or product. Either the system is very large, the infinite copy model (as described in Section 9.6) or one in which we calculate the molar... 

Measure the change in total volume V of the solution when one mole of solute is added to a very large quantity (strictly speaking, an infinite quantity) of the solution at the desired concentration. Because very large quantities of solution are used, the addition of one mole of solute does not change the concentration of the solution appreciably. As in the description of equrhbrium in Chapter 10, we may refer to the infinite copy model. ... 

The infinitely many (7-points represent infinitely many identical copies of our gas model, which started at time t from all the possible phases and which then move independently of each other, under similar conditions (i.e., the function E q, p) is the same for all of them). The fiction of such a host of infinitely many identical and independent gas models allows us to replace certain probability assumptions" by statistical statements. They were explicitly formulated and used first by Maxwell 13) (1878), and on this occasion he used the word statistico-mechanical" to describe the study of such ensembles of gas models (cf. note 3). However, seven years earlier Boltzmann [4] (1871) had already worked with essentially the same kind of ensembles, (cf. note 107). 

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