Consider the following reaction: H₂(g) + I₂(g) ⇌ 2 HI(g) Complete the table. Assume that all concentrations are equilibrium concentrations in M.
T (°C) [H₂] [I₂] [HI] Kc
25 0.0355 0.0388 0.922 _
340 _ 0.0455 0.387 9.6
445 0.0485 0.0468 _ 50.2

Verified step by step guidance

1. Identify the balanced chemical equation for the reaction: H2(g) + I2(g) ⇌ 2 HI(g).
2. Use the equilibrium constant expression for the reaction, Kc = \frac{[HI]^2}{[H2][I2]}, to set up the equation for each scenario provided in the table.
3. For each row in the table, substitute the given equilibrium concentrations of H2, I2, and HI into the Kc expression.
4. Calculate Kc by solving the expression for each set of concentrations. Remember to square the concentration of HI since it has a coefficient of 2 in the balanced equation.
5. Ensure the units are consistent and that all concentrations are in moles per liter (M) before substituting them into the Kc expression.

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 the given reaction, H2 and I2 combine to form HI, and at equilibrium, the concentrations of all species remain unchanged over time. Understanding this concept is crucial for analyzing the provided equilibrium concentrations and calculating the equilibrium constant (Kc).

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. For the reaction H2(g) + I2(g) ⇌ 2 HI(g), Kc is calculated as [HI]^2 / ([H2][I2]). This constant provides insight into the position of equilibrium and how it shifts with changes in concentration or temperature.

Le Chatelier's Principle

Le Chatelier's Principle states that if a dynamic equilibrium is disturbed by changing the conditions, the system will adjust to counteract the change and restore a new equilibrium. This principle helps predict how changes in temperature, pressure, or concentration will affect the equilibrium position of the reaction. In the context of the question, understanding this principle is essential for interpreting how Kc values might vary with temperature.