This module uses screencasts and interactive simulations to explain how to apply the first law of thermodynamics (energy balance) and mass balances to open systems that contain tanks with ideal gases or liquids and/or vapors. This includes releasing a gas from a tank, adding a gas to a tank, or evaporating a liquid into a vacuum. It then provides and an example problem to allow the users to test themselves. 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 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 screencasts or working with the simulations.
2. Watch the screencasts that describe unsteady-state energy balances on tanks and answer the questions within the screencasts.
3. Review important equations for unsteady-state energy balances on tanks.
4. Use the interactive simulations to further understand these energy balances.
5. Try to solve the example problem before watching the solution in the screencast.
6. Answer the ConcepTests.
7. Look at the list of key points, but only after you try to list the key points yourself