Phase Diagrams of Partially-Miscible Liquids Example Problems


Try to solve the problems before watching the solutions in the screencasts.

Example Problem 1

One mole of a liquid mixture that is 75% B and 25% A is heated at constant pressure in a piston and cylinder until 0.05 mol of vapor are present. List all phases present, their compositions, and their amounts. 

Example Problem 2

A cyclohexane-water system system is at equilibrium at 50°C. The system contains two liquid phases and a vapor phase. The α liquid phase is rich in cyclohexane, and the β liquid phase is rich in water. Cyclohexane is more volatile as a pure component than is water. The temperature is decreased to 45°C at constant pressure. Which of the following will occur:

    (i) Some of the vapor will condense, with more water condensing than cyclohexane.

    (ii) Some of the vapor will condense, with more cyclohexane than water.

    (iii) Some of the vapor will condense, with more cyclohexane condensing than water.

    (iv) none of the above.

Explain.