Unit 7: Topic 5 - Magnitude of the Equilibrium Constant

Question 1

Explain the relationship between the equilibrium value and the rate at which the chemical reaction proceeds.

Answer 1

The equilibrium constant, K, is a fraction that represents the reaction at equilibrium, where the numerator is related to the concentration of the products and the denominator is related to the concentration of the reactants.

For K > 1, the concentrations of the products are larger than the concentrations of the reactants at equilibrium, so the forward reaction will be favored to proceed, in general. For larger K, such as K > 1000, the concentrations of products are much larger, and the reaction proceeds close to completion to achieve equilibrium.

For 0 < K < 1, the concentrations of the products will be less than that of the reactants at equilibrium, so the reverse reaction is generally favored. For smaller K, such as K < 10^-3, the concentrations of reactants are much larger, and the forward reaction barely proceeds at all.