Gibbs Free Energy and Phase Separation: ConcepTest and Example Problem

Try to answer this ConcepTest and solve the example problem before using this module. Studies show that trying to answer the questions before studying material improves learning and retention. We suggest that you write down the reasons for your answers. By the end of this module, you should be able to answer these on your own. Answers will be given at the end of this module.

A sample problem on change in free energy by composition.

Calculate \(\Delta G\) for a binary liquid mixture at 75°C that has a mole fraction of 0.30 for component 1 (x1). The vapor in equilibrium with the liquid has a pressure of 0.31 bar and a mole fraction of 0.65 for component 1 (y1). The saturation pressures are: P1sat  = 0.33 bar; P2sat = 0.10 bar.