JChemEd Article Describes an Equilibrium Teaching and Learning Activity

AACT members now have access to 25 ACS Publications articles each year. We will highlight one article each month that you'll want to consider downloading through this new member benefit. This month we are featuring a hands-on student activity from the September 1998 issue of the Journal of Chemical Education titled, Equilibrium: A Teaching/Learning Activity, by Audrey H. Wilson.

The concept of chemical equilibrium is one of the most difficult topics for students to grasp and they develop quite a few misconceptions during the learning cycle. The author notes that there have been several classroom demonstrations offered on this topic in recent years. However, most require glassware, along with water or chemicals, making them more suitable as a teacher demonstration rather than a hands-on student activity. The activity outlined in this article can be done by small student groups working with small everyday items such as pennies, matches, or toothpicks.

By the end of this lesson, students should be able to recognize when equilibrium is reached and observe that at equilibrium, the concentration of products and reactants remain constant. Additionally, they will understand that at equilibrium the rates of the forward and reverse reactions are the same and that equilibrium can be approached from many starting points and from both directions.

During the lesson, the small student groups are further divided into “Reactants” and “Products” and exchange their small items as designated by the initial concentration and reaction rates. The lesson includes three activities, with each altering the initial concentration, forward and reverse reaction rates, and temperature. During each of the activities, students record data and draw conclusions about what it means to reach equilibrium.

Student Data Table for Activity 1

Note following the publication of the original article, there were modifications suggested in the September 2007 and November 2000 issues of the Journal of Chemical Education.

AACT has created a student activity sheet, answer key, and teacher notes to accompany the activity. If you have a favorite ACS Publication article that you use in your classroom, please share it with us at AACTconnect@acs.org.