Medical College Admission Test (MCAT) General Chemistry Practice Exam 2026 - Free MCAT Chemistry Practice Questions and Study Guide

The equilibrium constant (K) is defined as the ratio of the concentrations of products to the concentrations of reactants at equilibrium, each raised to the power of their respective stoichiometric coefficients. Importantly, K is dependent primarily on the temperature of the system.

At a given temperature, the value of K remains constant for a particular reaction, regardless of concentrations or pressures of the reactants and products. However, if the temperature changes, it can affect the rates of the forward and reverse reactions, leading to a new equilibrium position and consequently a new value for K.

While pressure and concentration can influence the position of equilibrium (the actual concentrations of reactants and products at equilibrium), they do not change the value of the equilibrium constant itself. Therefore, it is clear that temperature is the critical factor influencing the equilibrium constant.