The goal of this assignment is to learn about chemical equilibrium. Most reactions do not proceed completely from reactants to products, and equilibrium helps scientists to understand the extent of a given reaction.

Chapter 15 introduces us to chemical equilibrium. We will learn about the distribution of products to reactants over time, and we will use the equilibrium constant, K, to determine if a reaction is more product favored or reactant favored. For systems not at equilibrium, we shall use the reaction quotient, Q, to determine the course of a given reaction. We will learn about the connection between the equilibrium constant and the kinetics rate constant, k. We shall also explore the concept of Le Chatelier's Principle to determine the probable effect upon a reaction when adding or removing chemicals or changing conditions.

For a complete list of important concepts, see the Chapter 15 Study Guide.

To understand equilibrium, you should read Chapter 15 in your textbook.

The following screencasts might prove useful to you as you study this chapter. Note that you must have Quicktime installed to watch these screencasts.

• An Introduction to Equilibrium
• Using the Equilibrium Constant
• Manipulating the Equilibrium Constant
• Understanding the Value of K (and Q)
• Using the K Value to Calculate Equilibrium Concentrations
• Le Chatelier's Principle

The Chapter Fifteen PowerPoint lecture notes which accompany this lesson will be helpful to you when going through this section. These are Web versions of the PowerPoint notes I use in my "normal" CH 223 class and should let you see what is important to me in this chapter.

A variety of handouts are available from Chapter Fifteen. Feel free to explore all of them or just the ones which give you difficulty.

• Types of Equilibrium Constants
• Understanding K and Q
• Manipulating Equilibrium Constant Expressions
• Guide to Le Chatelier's Principle

• Simulation: Equilibrium State
• Simulation: Equilibrium Constant
• Simulation: The Meaning of the Equilibrium Constant
• Simulation: Writing Equilibrium Expressions
• Chemical Equilibrium
• Tutor: Writing Equilibrium Expressions
• Tutor: Determining the Equilibrium Constant
• Tutor: Systems at Equilibrium
• Simulation: Chromatography and Equilibrium
• Tutor: Estimating Equilibrium Concentrations
• Le Chatelier's Principle
• Tutor: Effect of Temperature on Equilibrium
• Simulation: Disturbing a Chemical Equilibrium
• Tutor: Addition of a Reagent and Equilibria
• Simulation: Equilibria and Volume

These interactive exercises from W.W. Norton and Company (ChemTours) might prove useful as well:

• Equilibrium
• Equilibrium in the Gas Phase
• Le Chatelier's Principle
• Solving Equilibrium Problems

Once you have mastered the concepts listed above, check out the Chapter Fifteen Concept Guide for a series of worked problems relating to this chapter. They will help you to ensure the mastery of the knowledge from this chapter.

Finally, test yourself (and get extra-credit in the bargain!) on the following introductory chemistry concepts. Remember that you must have JavaScript enabled on your browser! If you get 9 out of 10 correct (or some multiple thereof), submit the information to me to receive extra credit.

1. Calculating the Value of an Equilibrium Constant, K
2. Calculating K Part II
3. Calculating an Equilibrium Concentration
4. Q vs K
5. The Le Chatelier Effect
6. Combining Equilibria
7. K_p and K_c

Feel free to explore and discuss the ideas from this chapter with the class. Equilibrium can be applied to much more than chemistry; do you see examples of equilibrium in your own life? Take time to share your thoughts with the class on Discus regarding your impressions of these concepts and as how they relate to your life.

Please complete problem set #1 to further explore the idea of chemical equilibrium. Problem set #1 covers several questions from Chapter 15, and it can be found here. We will discuss problems like these during recitation, so come prepared to ask and answer questions.

For additional practice, try the non-assigned problems in Chapter 15. Answers to many of those problems are listed in the back of your textbook or in the Chapter Fifteen Student Solutions Manual.

If you need assistance on these problems, you have several options. You can visit the Learning Success Center located above the MHCC library on the Mt. Hood Community College campus; they have tutors available to help you with your chemistry homework. You can also contact me if you have any questions.