Final answer:
At equilibrium, the concentrations of the reactants and products remain constant. The equilibrium constant (Kc) is a measure of the ratio of the product concentrations to the reactant concentrations at equilibrium.
Step-by-step explanation:
At equilibrium, the concentrations of the reactants and products remain constant. In the reaction 2SO₂(g) + O₂(g) ↔ 2SO₃(g), the equilibrium constant (Kc) is a measure of the ratio of the product concentrations to the reactant concentrations at equilibrium. For example, if Kc = 4, it means that at equilibrium, the concentration of SO₃ is four times larger than the concentrations of SO₂ and O₂.