Chemical Potentials of Real Solutions. Activity

In this frame we shall discuss solutions of liquids although what is said applies equally well also to solid solutions. 

1 Chemical Potential, ai liquid mixture) for a Rea (Non-Ideal) Liquid Mixture. Activity, a 

We begin by restating the equation (35.16), Frame 35 that we established to hold for the pure liquid solvent in an ideal liquid mixture, this time writing /u.(i)(Ilqmd mixture) as (ldeai liquid mixture) Thg chemical potential, /x(i)(Klealhqmdmlxture), for an jdeai liquid mixture is then  

In real (non-ideal) liquid mixtures quite often equation (39.1) is simply not valid. Nor is the one (i.e. equation (36.8), Frame 36) holding for the solute in ideal dilute solution, which took the form  

M0)(ideal dilute solution) = M (j)(pure solute) + r lnXj (39.2) 

Following the ideas of Frame 38 (for gases) we can again define an alternative equation to cover departures from ideality and hence formulate one which will apply to real solutions, this takes the form  

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Chemical Potentials of Real Solutions. Activity, a and Activity Coefficients, f... 

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