By this point, you should have a solid conceptual understanding of dynamic equilibrium. This lesson will investigate the quantitative aspects of chemical reaction equilibrium systems.

It is important to be able to predict the amount of product formed in a chemical reaction. Previously you have used stoichiometry to calculate the mass of a product, assuming that the only limiting factor is the presence of a limiting reagent. In these cases, you assumed that the reaction went to completion and that the limiting reagent was consumed completely. However, as you have just learned, many reactions do not go to completion. Instead, the reaction reaches a state of dynamic equilibrium in which the reactants and products are both present.

All equilibria have various ratios of products to reactants. Some chemical reaction equilibrium systems contain mainly reactants, some contain mostly products, and some contain approximately equal amounts of reactants and products. However, note that any particular equilibrium system will always reach the same point of equilibrium given the same set of circumstances.