Equilibrium should be a familiar topic for your students, at least in terms of homeostasis from their biology class. My state has removed any equilibrium calculations from our state standards, so I don’t technically have to show them how to calculate K or Q. I like to because it helps them build better mathematical thinking skills. Solving for K is not difficult (especially if you give them concentration already in Molarity). For a challenge, give them grams and milliliters- but is that the focus for our equilibrium unit?
I struggle every year with a good wet lab for equilibrium. There are some advanced labs and some decent demos floating around on the internet, but safe labs that aren’t just moving water around, at least for me, have been hard to come by. I like to get my students moving at the start of this unit with a Human Equilibrium activity. This helps them better develop a mental model of what the reaction particles are doing during equilibrium.
Chemical Equilibrium Lesson Plans
Total Duration: 6-8 days
Note: a day refers to 45-50 minute periods.
| Topic & Timeline | Tasks | Description |
| Reversible Reactions 1-2 days | Human Equilibrium activity Equilibrium Demo/Lab OPTIONAL: Equilibrium POGIL Equilibrium Notes | Now that our students understand dynamic equilibrium, we can show them how to express equilibrium as a ratio of products to reactants. My cooperating teacher only ever had her students set up K, and never calculated it. I think this is a mistake. Once you can set up K calculating it is pretty simple. Just plug in the concentrations. Comparing K’s can help them with logical, mathematical thinking. |
| Calculating K 1 day | Writing Equilibrium Expressions Notes | Once they know how to calculate K, calculating Q is a snap! Again, comparing Q to K is a great mathematical practice. Referring back to their movement lab, Q is at ANY time. K is when they know for sure they hit equilibrium. |
| Comparing K and Q 1 day | Reaction Quotient Notes | Once they know how to calculate K, calculating Q is a snap! Again, comparing Q to K is a great mathematical practice. Referring back to their movement lab, Q is at ANY time. K is when they know for sure they have hit equilibrium. |
| LeChatelier’s Principle 1-2 days | LeChatelier’s Principle Notes | Have your students perform the human equilibrium lab again. Add some stressors by shouting out new conditions (it’s really hot outside, the hallway is shrinking, etc). They will probably intuitively make adjustments. Discuss how reversible reactions adjust just like they did to new conditions. |
| Review 1 day | Equilibrium Vocabulary Study Guide | |
| Assessment 1 day |
Further Reading
The Chemistry Particle’s Guide to Teaching High School Chemistry, The Chemistry Particle
Chemical Equilibrium Notes Bundle, TeachersPayTeachers
Equilibrium Practice Pages, Matt Fry
