Consider a reaction A₂(𝑔) + B₂(𝑔) ⇌ 2 AB(𝑔), atoms of A shown in red in the diagram and atoms of B shown in blue. (a) If 𝐾_𝑐 = 1, which box represents the system at equilibrium?

Key Concepts

Chemical Equilibrium

Chemical equilibrium occurs in a reversible reaction when the rates of the forward and reverse reactions are equal, resulting in constant concentrations of reactants and products. In this state, the system appears static, but molecular activity continues. The equilibrium constant (Kc) quantifies the ratio of product concentrations to reactant concentrations at equilibrium, providing insight into the position of equilibrium.

Equilibrium Constant (Kc)

The equilibrium constant (Kc) is a numerical value that expresses the ratio of the concentrations of products to reactants at equilibrium, raised to the power of their stoichiometric coefficients. A Kc value of 1 indicates that the concentrations of reactants and products are equal at equilibrium, suggesting that neither side is favored. This concept is crucial for predicting the direction of a reaction and understanding the balance between reactants and products.

Le Chatelier's Principle

Le Chatelier's Principle states that if a dynamic equilibrium is disturbed by changing the conditions (such as concentration, temperature, or pressure), the system will adjust to counteract the change and restore a new equilibrium. This principle helps predict how a system will respond to changes, such as adding or removing reactants or products, and is essential for understanding the behavior of chemical reactions at equilibrium.