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. (b) If 𝐾_𝑐 = 1, which box represents the system at 𝑄 < 𝐾_𝑐?

Verified step by step guidance

1. Step 1: Understand the concept of the reaction quotient (Q) and the equilibrium constant (Kc). The reaction quotient is a measure of the relative amounts of products and reactants present during a reaction at a particular point in time. The equilibrium constant (Kc) is the value of the reaction quotient when the reaction is at equilibrium.
2. Step 2: In this case, the reaction is A2(g) + B2(g) ⇌ 2 AB(g). The reaction quotient Q is given by the formula Q = [AB]^2 / ([A2][B2]), where the brackets denote the concentrations of the species.
3. Step 3: If Q < Kc, it means that the reaction is not at equilibrium and will proceed in the forward direction to reach equilibrium. This implies that the concentrations of the reactants (A2 and B2) are higher than that of the product (AB).
4. Step 4: Look at the boxes in the diagram. The box that represents the system at Q < Kc will have more molecules of A2 and B2 (reactants) than molecules of AB (product).
5. Step 5: Remember that in the diagram, atoms of A are shown in red and atoms of B are shown in blue. So, molecules of A2 will be represented by two red atoms together, molecules of B2 will be represented by two blue atoms together, and molecules of AB will be represented by one red and one blue atom together.

Key Concepts

Chemical Equilibrium

Chemical equilibrium occurs when the rates of the forward and reverse reactions are equal, resulting in constant concentrations of reactants and products. In this state, the system is dynamic, meaning that reactions continue to occur, but there is no net change in the concentrations. Understanding this concept is crucial for analyzing the position of equilibrium in a reaction.

Reaction Quotient (Q)

The reaction quotient (Q) is a measure of the relative concentrations of products and reactants at any point in time during a reaction. It is calculated using the same expression as the equilibrium constant (K), but with the current concentrations. Comparing Q to K helps determine the direction in which a reaction will proceed to reach 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 for a given reaction at a specific temperature. A Kc value of 1 indicates that the concentrations of products and reactants are equal at equilibrium. This concept is essential for predicting the behavior of a reaction and understanding how changes in conditions affect the system.