Final answer:
The reaction quotient (Qc) is a measure that helps predict the direction a reaction will take to reach equilibrium. It compares the current concentrations of reactants and products to the equilibrium constant (K), adjusting the reaction's direction accordingly to achieve equilibrium.
Step-by-step explanation:
The reaction quotient, Qc, is a measure used in chemistry to determine the progress of a reaction towards equilibrium. It is calculated using the Law of Mass Action and has a similar form to the equilibrium constant, K. The reaction quotient is calculated from the current concentrations of reactants and products in a reaction mixture, regardless of whether the system has reached equilibrium.
When Qc is less than K, the reaction will shift in the forward direction to increase the value of Qc towards that of K. If Qc is greater than K, the reaction will move in the reverse direction, decreasing Qc until it equals K and equilibrium is achieved.
During this process, as the reaction moves forward, reactant concentrations decrease while product concentrations increase, leading to a change in Qc until it no longer changes, indicating that equilibrium has been reached. This tool allows chemists to predict the direction in which a nonequilibrium system will shift in order to reach equilibrium.