Wrap-Up

In this lesson, we have studied chemical reaction rates, the energies associated with chemical reactions, and chemical equilibria. We started by developing the reaction coordinate diagram framework for analyzing two important features of a reaction: its activation energy and its enthalpy.

From our understanding of activation energy, collision theory provides a basis for understanding reaction rate in terms of the need for collisions with sufficient energy and effective orientation. On that basis, we learned reaction rate can be influenced by concentration, surface area, temperature, and catalysts.

Collision theory also provides an explanation for the development of equilibria in reversible reactions, and for Le Chatelier's Principle, wherein a reaction responds to a disruption of an equilibrium in a way that counters the disruption.

Finally, we expanded our use of equilibrium expressions to include any reaction at equilibrium; now you are able to write an equilibrium expression for solubility product equations, for acid and base dissociation equations, and for any other reaction at equilibrium. Given the equilibrium constant and/or the individual concentrations of the various chemicals, you are able to solve equilibrium expression equations for the missing variable.