Thermodynamics of Mixing The simplest example of mixing: What is the Gibbs free energy if we take two pure ideal gases and mix them together? Consider gas a and gas B, both in separate containers at pressure p at temperature T The chemical potentials are at their "pure values"at this point. Gibbs energy is ∵ μA e矿4 RT In nUb+ RT In A B P We can simplify things by letting p denote the 3 pressure relative to p, writing + RT In pi+bLub+ RT In p