What can be said about the concentration of products when:

Question

a) the equilibrium constant is large

b) the equilibrium constant is small

Answer 1

The equilibrium constant expression of a reaction is set up as the concentrations of products divided by the concentrations of reactants, with each concentration raised to an exponent that matches its coefficient in the balanced chemical equation. Note that solids and liquids are never included in setting up an equilibrium constant expression.

For the general reaction A(aq) + B(aq) --> C(aq) + D(aq) the equilibrium constant expression would be written as:

K = [C][D]/[A][B]

a.) Since the equilibrium constant expression is set up as the concentrations of products divided by the concentrations of reactants, if K is greater than 1 this indicates that the concentrations of the products are greater than the concentrations of the reactants. Equilibrium is said to lie to the right.

b.) If K is less than 1 this indicates that the concentrations of the products are less than the concentrations of the reactants. Equilibrium is said to lie to the left.