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

The maximum grams of salt that dissolve per liter

Answer

The rate at which the salt dissolves in water

Answer

The concentration of the undissolved solid

Question 2

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

Accepted Answer

Ksp = [Ag⁺]²[CrO₄²⁻]

Answer

Ksp = [Ag⁺][CrO₄²⁻]

Answer

Ksp = [2Ag⁺][CrO₄²⁻]

Answer

Ksp = [Ag⁺]²[CrO₄²⁻] / [Ag₂CrO₄]

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

1.1 × 10⁻¹⁰ M

Answer

5.5 × 10⁻¹¹ M

Answer

2.2 × 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

NaCl reacts with AgCl to form an insoluble precipitate

Answer

Na⁺ ions compete with Ag⁺ ions for binding sites

Answer

The ionic strength decreases the activity of Ag⁺

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

K^(1/2)

Answer

K^(1/4)

Answer

1/K^(1/4)

Question 6

At equilibrium, the Gibbs free energy change (ΔG) for the reaction equals:

Accepted Answer

Zero

Answer

The standard free energy change ΔG°

Answer

−RT ln K

Answer

A positive value indicating stability

Question 7

Which relationship correctly connects the standard Gibbs free energy change ΔG° to the equilibrium constant K?

Accepted Answer

ΔG° = −RT ln K

Answer

ΔG° = RT ln K

Answer

ΔG° = −R ln K / T

Answer

ΔG° = RT / K