Single-Component Phase Equilibrium: Summary

The answers to the ConcepTests are given below and will open in a separate window. 
Key points from this module:
  • The phase diagrams (P-V, P-T, V-T) typically used to represent single-component phase behavior are 2-D projections of a 3-D surface.
  • A liquid can be converted to a vapor without the co-existence of two phases by circumnavigating the critical point.
  • At a given pressure, vapor and liquid are in equilibrium at only one temperature.
From studying this module, you should now be able to:
  • Determine the state of a single-component system at a given pressure and temperature, given a phase diagram.
  • Explain how a single-component system changes as temperature or pressure changes.
  • Explain the significance of a critical point and identify it on a single-component phase diagram.
  • Explain how a liquid can become a vapor without going through a phase change.
  • Draw a pressure-temperature diagram.
  • Identify melting point and boiling point on a P-T diagram at a selected pressure.
  • Identify the triple point on a P-T diagram and explain what phases are present at the triple point.

Prepared by John L. Falconer, Department of Chemical and Biological Engineering, University of Colorado Boulder
Additional related screencasts include: