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Key Terms

ChemistryKey Terms

in chemical reactions, the state in which the conversion of reactants into products and the conversion of products back into reactants occur simultaneously at the same rate; state of balance
equilibrium constant (K)
value of the reaction quotient for a system at equilibrium
heterogeneous equilibria
equilibria between reactants and products in different phases
homogeneous equilibria
equilibria within a single phase
equilibrium constant for reactions based on concentrations of reactants and products
equilibrium constant for gas-phase reactions based on partial pressures of reactants and products
law of mass action
when a reversible reaction has attained equilibrium at a given temperature, the reaction quotient remains constant
Le Châtelier's principle
when a chemical system at equilibrium is disturbed, it returns to equilibrium by counteracting the disturbance
position of equilibrium
concentrations or partial pressures of components of a reaction at equilibrium (commonly used to describe conditions before a disturbance)
reaction quotient (Q)
ratio of the product of molar concentrations (or pressures) of the products to that of the reactants, each concentration (or pressure) being raised to the power equal to the coefficient in the equation
reversible reaction
chemical reaction that can proceed in both the forward and reverse directions under given conditions
change to a reaction's conditions that may cause a shift in the equilibrium
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