Sulfur dioxide reacts with oxygen in a step in the production of sulfuric acid. 2 SO2(g) + O2(g) ⇌ 2 SO3(g), Kc = 7.9 * 10^4 at 1800 K. For an equilibrium mixture in which [SO2] = 4.5 * 10^-3 M and [O2] = 1.5 * 10^-3 M, what is [SO3]? (LO 15.4) (a) [SO3] = 6.2 * 10^-7 M (b) [SO3] = 4.9 * 10^-2 M (c) [SO3] = 0.73 M (d) [SO3] = 2.4 * 10^-3 M

Verified step by step guidance

Step 1: Write the expression for the equilibrium constant, Kc, for the reaction: Kc = [SO3]^2 / ([SO2]^2 * [O2]).

Step 2: Substitute the given values into the Kc expression: Kc = 7.9 * 10^4, [SO2] = 4.5 * 10^-3 M, and [O2] = 1.5 * 10^-3 M.

Step 3: Rearrange the Kc expression to solve for [SO3]^2: [SO3]^2 = Kc * ([SO2]^2 * [O2]).

Step 4: Calculate [SO2]^2 and multiply it by [O2] to find the denominator value.

Step 5: Multiply the result from Step 4 by Kc to find [SO3]^2, then take the square root to find [SO3].

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 concentration. Understanding equilibrium is crucial for solving problems involving equilibrium constants (Kc) and concentrations.

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 expressed as Kc = [products]^[coefficients] / [reactants]^[coefficients]. A large Kc value, such as 7.9 * 10^4, indicates that at equilibrium, the concentration of products is much greater than that of reactants, guiding the calculation of unknown concentrations.

Concentration Calculations

Concentration calculations involve determining the molarity of substances in a solution, which is essential for applying the equilibrium expression. In this problem, the concentrations of SO2 and O2 are provided, and using the Kc value, one can rearrange the equilibrium expression to solve for the unknown concentration of SO3. This requires an understanding of stoichiometry and the relationships between reactants and products.

Recommended video:

Guided course

07:35

Calculate Concentration of the Basic Form

Related Practice

Textbook Question

The reaction A21g2 + B21g2 ∆ 2 AB1g2 has an equilib- rium constant Kc = 9. The following figure represents areaction mixture that contains A2 molecules (red), B2 mol- ecules (blue), and AB molecules. What statement about the mixture is true? (LO 15.5)

(a) The mixture is at equilibrium, and there will be no net shift in reaction direction.(b) The reaction will shift toward the reactants to reach equilibrium.(c) The reaction will shift toward the products to reach equilibrium.(d) More information is needed to answer this question.

views