Interactive Self-Study Module: Single-Component Phase Equilibrium


This module uses screencasts and interactive simulations to explain the phase equilibrium of a single-component. It explains phase diagrams, including vapor-liquid equilibrium and the critical point. Your retention of material in this module will increase if you write down reasons for your answers to ConcepTests, questions in screencasts, and questions to answer before using interactive simulations, and you try to solve the example problems before watching the screencast solutions. We suggest using the learning resources in the following order:

  1. Attempt to answer the multiple choice ConcepTest and solve the example problem before watching the screencasts or working with the simulations.
  2. Watch the screencasts that describe the phase diagrams and answer the questions within the screencasts.
  3. Review important equations for single-component phase equilibrium.
  4. Use the interactive simulations to further understand the behavior of the phase diagrams.
  5. Try to solve the example problems before watching the solutions in the screencasts.
  6. Answer the ConcepTests.
  7. Look at the list of key points, but only after you try to list the key points yourself.
  • Understanding single-component phase behavior is important for many processes in chemical engineering and necessary to understand multi-component phase behavior.
  • This module is intended for a thermodynamics course and may also be useful for a materials and energy balances course.
Before studying this module, you should:
  • Be able to apply the Antoine equation to determine saturation pressure of a single component at a given temperature.
After studying this module, you should 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.