Chemical equilibrium describes the composition at which a reacting system reaches a minimum Gibbs function and experiences no net spontaneous change. In this chapter, we develop the thermodynamic relationships between Gibbs energy, chemical potential, equilibrium constants, and reaction composition, and examine how equilibrium responds to changes in pressure, composition, and temperature. These principles are then applied to a variety of important chemical systems, including dissociation equilibria, acid-base reactions, buffer solutions, and solubility equilibria.
Learn how chemical equilibrium arises from the tendency of systems to minimize the Gibbs function. You will connect equilibrium composition to chemical potential and the criterion for spontaneous change.
Develop the relationship between the standard Gibbs energy change and the thermodynamic equilibrium constant. You will also examine the role of activities and fugacities in the rigorous thermodynamic treatment of equilibrium.
Explore how equilibrium compositions respond to changes in pressure, volume, and composition. Reaction quotients, equilibrium constants, and Le Chatelier's principle will be used to predict and explain these changes.
Use ICE-table methods to determine equilibrium compositions for chemical systems. Applications include dissociation equilibria and calculations involving the degree of dissociation.
Derive and apply the van't Hoff equation to understand how equilibrium constants vary with temperature. You will also learn how equilibrium measurements can be used to determine reaction enthalpies.
Apply the principles of chemical equilibrium to important chemical systems, including acid-base equilibria, buffer solutions, hydrolysis reactions, and solubility equilibria. These examples illustrate how equilibrium concepts are used throughout chemistry.