CHEM 120B Lecture Notes - Lecture 6: Equilibrium Constant, Chemical Equilibrium, Reaction Rate Constant
Document Summary
Chemical reactions still occur at equilibrium; that is, the average rate of change is zero but there is still movement that maintains this even amount of change: equilibrium is dynamic. Chemical equilibrium occurs when the net rate of reaction is zero. The rate of the reaction going forward (product formation) is the same as the rate of the reaction going backwards (reactant formation); no net change. Equilibrium constant (k): tells the relative amount of products and reactants: distinct from lower-case (k), which is representative of rate constant. The equilibrium constant expression: solids and liquids are never included in this equation; gases and aqueous solutions are always included. The concentrations of solids and liquids do not change. Does not depend on when/where. the reaction begins. Relates to the stoichiometry of the balanced reaction and applies only at equilibrium. Can be expressed in terms of partial pressures or concentrations; however, they cannot be mixed within the same constant.