A sample of HI 19.30 * 10^-3 mol^2 was placed in an empty 2.00-L container at 1000 K. After equilibrium was reached, the concentration of I2 was 6.29 * 10^-4 M. Calculate the value of Kc at 1000 K for the reaction H2(g) + I2(g) ⇌ 2 HI(g).

Verified step by step guidance

Identify the balanced chemical equation for the reaction: \( \text{H}_2(g) + \text{I}_2(g) \rightleftharpoons 2 \text{HI}(g) \).

Write the expression for the equilibrium constant \( K_c \) for the reaction: \( K_c = \frac{[\text{HI}]^2}{[\text{H}_2][\text{I}_2]} \).

Determine the initial concentration of HI by dividing the initial moles by the volume of the container: \( \frac{19.30 \times 10^{-3} \text{ mol}}{2.00 \text{ L}} \).

Use the stoichiometry of the reaction to express the changes in concentration of \( \text{H}_2 \), \( \text{I}_2 \), and \( \text{HI} \) in terms of a variable \( x \), where \( x \) is the change in concentration of \( \text{I}_2 \) at equilibrium.

Substitute the equilibrium concentrations into the \( K_c \) expression and solve for \( K_c \).

Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Equilibrium Constant (Kc)

The equilibrium constant, Kc, quantifies the ratio of the concentrations of products to reactants at equilibrium for a given reaction at a specific temperature. It is calculated using the formula Kc = [products]^coefficients / [reactants]^coefficients. A larger Kc value indicates a greater concentration of products at equilibrium, while a smaller Kc suggests a higher concentration of reactants.

Concentration and Molarity

Concentration refers to the amount of a substance in a given volume of solution, commonly expressed in molarity (M), which is moles of solute per liter of solution. In this problem, the concentration of I2 is given as 6.29 * 10^-4 M, indicating the number of moles of I2 present in one liter of the solution. Understanding how to convert moles to molarity is crucial for calculating Kc.

Stoichiometry of the Reaction

Stoichiometry involves the quantitative relationships between the reactants and products in a chemical reaction. For the reaction H2(g) + I2(g) ⇌ 2 HI(g), the stoichiometric coefficients indicate that one mole of H2 reacts with one mole of I2 to produce two moles of HI. This relationship is essential for determining the concentrations of all species at equilibrium, which are needed to calculate Kc.

Recommended video:

Guided course

01:16

Stoichiometry Concept

Related Practice

Textbook Question

Calculate the equilibrium concentrations at 25 °C for the reaction in Problem 15.84 if the initial concentrations are 3N2O44 = 0.0200 M and 3NO24 = 0.0300 M.

Textbook Question

The industrial solvent ethyl acetate is produced by the reac-tion of acetic acid with ethanol:CH3CO2H1soln2 + CH3CH2OH1soln2 ∆CH3CO2CH2CH31soln2 + H2O1soln2Ethyl acetate (b) A solution prepared by mixing 1.00 mol of acetic acid and 1.00 mol of ethanol contains 0.65 mol of ethyl ace- tate at equilibrium. Calculate the value of Kc. Explain why you can calculate K without knowing the volume of the solution.

views