Equilibrium Constant for Chemical Reactions

This article discusses the equilibrium constant for chemical reactions. The equilibrium constant is a measure of the extent to which a reaction has gone to completion. It is calculated using the concentrations of the reactants and products at equilibrium.

Questions

1. What is the equilibrium constant?
2. How is the equilibrium constant calculated?
3. Why are solids and liquids omitted from the equilibrium constant?
4. What are the units of the equilibrium constant?

Answers

1. The equilibrium constant is a measure of the extent to which a reaction has gone to completion. It is calculated using the concentrations of the reactants and products at equilibrium.
2. The equilibrium constant is calculated using the following formula:

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   K = [products] / [reactants]

   where [products] is the concentration of the products at equilibrium and [reactants] is the concentration of the reactants at equilibrium.

3. Solids and liquids are omitted from the equilibrium constant because their concentrations are essentially constant. This is because the volumes of solids and liquids are basically constant, so their activities are therefore 1. The activities of solids and liquids equal 1.
4. The units of the equilibrium constant depend on the reaction. For reactions involving gases, the units of the equilibrium constant are moles per liter (mol/L). For reactions involving solids and liquids, the units of the equilibrium constant are dimensionless.