# Chapter 9: Mixtures

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$$\newcommand{\el}{\subs{el}} % electrical$$
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A homogeneous mixture is a phase containing more than one substance.  This chapter discusses composition variables and partial molar quantities of mixtures in which no chemical reaction is occurring.  The ideal mixture is defined.  Chemical potentials, activity coefficients, and activities of individual substances in both ideal and nonideal mixtures are discussed.

Except for the use of fugacities to determine activity coefficients in condensed phases, a discussion of phase equilibria involving mixtures will be postponed to Chap. 13.