#### Interactive Self-Study Module: Chemical Equilibrium for Multiple Reactions

##### Overview:

This module uses screencasts to explain how to calculate chemical equilibrium using Gibbs free energy minimization. It then provides example problems 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 ConcepTests, questions in screencasts, and you try to solve the example problems before watching the solutions in the screencasts. We suggest using the learning resources in the following order:

- Attempt to answer the multiple-choice ConcepTest and solve the example problem before watching the screencasts or working with the simulations.
- Watch the screencasts that describe calculations of Gibbs free energy change as a function of temperature and how to minimize Gibbs free energy to determine chemical equilibria. Try to answer the questions within the screencasts. Use the spreadsheets to better understand the calculations.
- Review important equations for chemical equilibrium for multiple reactions.
- Try to solve the example problems before watching the solutions in the screencasts.
- Answer the ConcepTests.
- Look at the list of key points, but only after you try to list the key points yourself.

##### Motivation:

- Most reaction systems involve more than one chemical reaction so it is necessary to calculate equilibrium for multiple reactions simultaneously. This can be done by Gibbs minimization.
- This module is intended for a thermodynamics course.

##### Before studying this module, you should be able to:

- Use temperature-dependent Heat Capacities to calculate enthalpy changes.
- Determine Heats of Reaction as a function of temperature using heats of formation and temperature-dependent heat capacities.
- Calculate equilibrium constants from Gibbs free energies of formation and determine equilibrium extents of reaction for Gas-Phase Chemical Equilibrium.
- Use spreadsheets and the Solver function as explained in Iterative Solutions of Nonlinear Equations.

##### After studying this module, you should be able to:

- Calculate Gibbs free energy of formation at standard conditions as a function of temperature.
- Calculate Gibbs free energy as a function of mole fraction and pressure.
- Use minimization of Gibbs free energy to determine equilibrium compositions for one or more simultaneous reactions.