Consider the reaction: CO(g) + 2 H2(g) ⇌ CH3OH(g). An equilibrium mixture of this reaction at a certain temperature has [CO] = 0.105 M, [H2] = 0.114 M, and [CH3OH] = 0.185 M. What is the value of the equilibrium constant (Kc) at this temperature?

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Identify the balanced chemical equation: CO(g) + 2 H2(g) ⇌ CH3OH(g).

Write the expression for the equilibrium constant, Kc, for the reaction: Kc = \( \frac{[\text{CH}_3\text{OH}]}{[\text{CO}][\text{H}_2]^2} \).

Substitute the given equilibrium concentrations into the Kc expression: [CO] = 0.105 M, [H2] = 0.114 M, [CH3OH] = 0.185 M.

Calculate the value of Kc using the substituted values: Kc = \( \frac{0.185}{0.105 \times (0.114)^2} \).

Simplify the expression to find the numerical value of Kc.

Key Concepts

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

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 of the substances involved.

Equilibrium Constant (Kc)

The equilibrium constant (Kc) is a numerical value that expresses the ratio of the concentrations of products to reactants at equilibrium, each raised to the power of their coefficients in the balanced equation. For the reaction CO(g) + 2 H2(g) ⇌ CH3OH(g), Kc is calculated using the formula Kc = [CH3OH] / ([CO][H2]^2), where the concentrations are measured in molarity.

Concentration Units

Concentration is a measure of the amount of a substance in a given volume, typically expressed in molarity (M), which is moles of solute per liter of solution. Understanding how to manipulate and interpret these units is essential for calculating equilibrium constants and analyzing chemical reactions.

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