Raoult's Law and Vapor-Liquid Equilibrium: Interactive Simulation

This simulation was prepared using Mathematica. Download the free CDF player, and then download the simulation CDF file (link below). Try to predict the behavior when a parameter changes before using a slider to change that parameter. For this simulation, a screencast is provided to explain how to use it.

Simulation: P-x-y and T-x-y Diagrams for VLE 

The vapor-liquid equilibrium (VLE) behavior of an n-hexane/n-octane mixture is demonstrated in P-x-y and T-x-y diagrams. The blue line represents the liquid-phase boundary (bubble point)and the green line represents the vapor-phase boundary (dew point). Click and drag the black dot on either diagram, and the bar chart shows the amount of liquid (blue) and vapor (green) present. The system contains a total of 1 mol. 

Try to answer these questions before determining the answer with the simulation:

  1. When the temperature increases, what happens to the two curves in the P-x-y diagram? Do they move to higher or lower pressure or do they not change? Why?
  2. If the black dot moves at constant overall composition to higher pressure at constant temperature in the P-x-y diagram, do the mole fractions of the liquid and vapor phases increase or decrease or does one increase and one decrease? 
  3. How is the T-x-y diagram different from the P-x-y diagram?