Reaction Quotient
What is Reaction Quotient?
The reaction quotient (Q) is the ratio of the concentrations (or partial pressures) of products to reactants at any point during a reaction, using the same expression as the equilibrium constant K. By comparing Q to K, the direction in which a reaction must proceed to reach equilibrium can be predicted: if Q < K the reaction moves forward; if Q > K it moves in reverse; and if Q = K the system is already at equilibrium. Q is an instantaneous snapshot while K is the value at equilibrium.
Key Facts
Frequently Asked Questions
The reaction quotient (Q) is the ratio of the concentrations (or partial pressures) of products to reactants at any point during a reaction, using the same expression as the equilibrium constant K. By comparing Q to K, the direction in which a reaction must proceed to reach equilibrium can be predicted: if Q < K the reaction moves forward; if Q > K it moves in reverse; and if Q = K the system is already at equilibrium. Q is an instantaneous snapshot while K is the value at equilibrium.