Equilibrium constants for gases can be expressed in terms of concentrations, K_c, or in terms of partial pressures, K_p. Which one of the following statements regarding K_c and K_p is correct?

Question

Quizplus · Accepted Answer

The equilibrium constant can be expressed as the ratio of the product of the concentrations (or partial pressures) of products raised to their stoichiometric coefficients and the product of the concentrations (or partial pressures) of reactants raised to their stoichiometric coefficients. Therefore, K_c and K_p will only be equal when the sum of the stoichiometric coefficients for the products equals the sum of the stoichiometric coefficients for the reactants. This is because the stoichiometric coefficients will cancel out when taking the ratio, resulting in the same value for both concentration and partial pressure expressions of the equilibrium constant.

Equilibrium Constants for Gases Can Be Expressed in Terms of Concentrations