$K_{eq}$: The equilibrium constant, a number that expresses the ratio of product concentrations to reactant concentrations at equilibrium for a given reaction.
Le Chatelier's Principle:A principle stating that if an external change is applied to a system at equilibrium, the system adjusts in such a way as to counteract that change and restore a new equilibrium.
Dynamic Equilibrium:A state where forward and reverse reactions occur at equal rates so that there is no net change in concentration of reactants and products.