Reaction Quotient

[Baria Alaswad 2E]

How does the value of Q compare to the equilibrium constant (K) at equilibrium?

[Ilia1B]

At equilibrium, Q=K. K, by definition, is the reaction quotient at equilibrium. Q would describe how a reaction would proceed if not at equilibrium concentrations, so if the reaction were at equilibrium, Q and K would be exactly the same.

[Cartor_Crisp_2A]

The formulas for the Reaction Quotient (Q) and the Equilibrium Constant (K) are identical, only differing in the times at which measurements are taken. For the Equilibrium Constant, the concentrations of reactants and products are taken when the reaction has reached equilibrium (the forward and reverse reaction equivalent), whereas the Reaction Quotient can be calculated experimentally at any point during the reaction or thereafter. The two are equal when the reaction has reached equilibrium.