Chemistry Test Chemical Equilibrium 3

Question 1

The solubility product constant (Ksp) for a sparingly soluble salt represents:

Accepted Answer

The equilibrium constant for the dissolution of a slightly soluble ionic compound

Answer

Ksp is the equilibrium constant specifically for the dissolution of a sparingly soluble ionic compound, with the solid excluded from the expression.

Question 2

What is the correct Ksp expression for the dissolution: Ag₂CrO₄(s) ⇌ 2Ag⁺(aq) + CrO₄²⁻(aq)?

Accepted Answer

Ksp = [Ag⁺]²[CrO₄²⁻]

Answer

The Ksp expression uses concentrations raised to stoichiometric powers; Ag⁺ has a coefficient of 2, so Ksp = [Ag⁺]²[CrO₄²⁻]. The solid is excluded.

Question 3

If the Ksp of BaSO₄ is 1.1 × 10⁻¹⁰, what is the molar solubility of BaSO₄?

Accepted Answer

1.05 × 10⁻⁵ M

Answer

BaSO₄ dissolves as Ba²⁺ + SO₄²⁻, so Ksp = s² = 1.1 × 10⁻¹⁰; solving gives s = √(1.1 × 10⁻¹⁰) ≈ 1.05 × 10⁻⁵ M.

Question 4

The common ion effect reduces the solubility of AgCl in a solution already containing NaCl because:

Accepted Answer

The extra Cl⁻ ions shift the dissolution equilibrium to the left

Answer

Adding Cl⁻ from NaCl increases [Cl⁻], making Q > Ksp for AgCl, which shifts the equilibrium left and causes more AgCl to precipitate, reducing solubility.

Question 5

The equilibrium constant for 2SO₂(g) + O₂(g) ⇌ 2SO₃(g) is K. What is the equilibrium constant for the reaction ½SO₃(g) ⇌ ½SO₂(g) + ¼O₂(g)?

Accepted Answer

1/K^(1/2)

Answer

Reversing the reaction gives K' = 1/K; halving the coefficients (multiplying equation by ½) gives K'' = (1/K)^(1/2) = K^(-1/2), or 1/√K.

Chemistry Practice Test Practice Test

Chemistry Practice Test Practice Test

Chemistry Test Chemical Equilibrium 3