Science

Equilibrium constant.

Definition

A value (K) that expresses the ratio of product concentrations to reactant concentrations at chemical equilibrium, each raised to the power of their coefficients. A large K means products are favored; a small K means reactants are favored.

Examples

Real-world.

  • 1 The formation of water from hydrogen and oxygen has a very large K, favoring products
  • 2 The dissociation of a weak acid like acetic acid has a small Ka
  • 3 Comparing Q (reaction quotient) to K to predict which direction a reaction will shift
Key Fact

K = [products]^coefficients / [reactants]^coefficients at equilibrium

Studied in

1 unit use this concept.