Interactive Self-Study Module: Absorption and Henry's Law


This module uses a screencast and an interactive simulation to explain Henry’s law, which relates the amount of gas dissolved in a liquid to the partial pressure of the gas. It applies at low concentrations of the dissolved gas. The module then provides an example problem to allow the user to test themselves. Your retention of material in this module will increase if you write down reasons for your answers to the ConcepTest, questions in the screencast, and questions to answer before using the interactive simulation, and you try to solve the example problem before watching the screencast solution. 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 screencast or working with the simulation.
  2. Watch the screencast that describes Henry’s law and answer the questions within the screencast.
  3. Review important equations for absorption and Henry’s law.
  4. Use the interactive simulation to further understand the behavior of gases dissolved in water.
  5. Try to solve the example problem before watching the solution in the screencast.
  6. Answer the ConcepTest.
  7. Look at the list of key points, but only after you try to list the key points yourself.
  • Absorption is used in separations processes, including removing contaminants from gas streams and absorbing gases in polymer membranes. This module is intended for a thermodynamics course or a separations course.
Before studying this module, you should:
  • Be able to apply Raoult’s law to calculate liquid compositions for vapor-liquid equilibrium (Raoult’s Law and VLE).
After studying this module, you should be able to:
  • Given the pressure of a gas and its Henry’s constant, calculate the mole fraction of a gas absorbed in a liquid.
  • Explain how the amount of gas absorbed depends on temperature and pressure.