Students tend to develop the following misconceptions concerning chemical equilibrium:

• Equilibrium means equal concentrations.
• Once equilibrium is achieved, the system becomes static. Nothing happens.

To combat these misconceptions, try the water analogy inquiry activity and force students to continue swapping water once equilibrium is reached. Emphasize the following definition:

Chemical Equilibrium - a dynamic state in which the concentrations of all reactants and products in a reaction remain constant with time.

Use dynamic analogies like the ratios of genders at the mall on a Sunday afternoon, or the types of cars on the interstate during the day.

Continually emphasize the following four points with students.

1. Equilibrium is a dynamic condition. Though concentrations of reactants and products reach a constant value, they are still being exchanged. If I give my friend 5% of the money I have and he gives me 10% of the money he has, at some point an equilibrium is established. At the established equilibrium point, money is still being exchanged but the amount of money exchanged remains constant.
2. Equilibrium is reached when the forward and reverse reaction rates are equal. Not when the species' concentrations are equal.
3. The equilibrium point is determined by thermodynamics.
4. The rate at which equilibrium is approached is determined by kinetics.