Acids, Bases, and Equilibrium

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Questions and Answers

Which of the following statements accurately describes the relationship between the strength of an acid and its acid dissociation constant (Ka)?

Ka only determines the reaction rate, not the acid strength.
A larger Ka indicates a stronger acid. (correct)
Ka is not related to the strength of an acid.
A larger Ka indicates a weaker acid.

What is the pH of a solution if the pOH is 6 at 25°C?

Cannot be determined.
8 (correct)
6
14

A weak acid, HA, has an initial concentration of 0.1 M and a degree of dissociation (α) of 0.02. What is the hydrogen ion concentration [H+] at equilibrium?

0.1 M
0.002 M (correct)
0.02 M
0.0002 M

Which of the following scenarios will result in a neutral solution (pH = 7) after salt hydrolysis?

Reaction of a strong acid and a strong base (A) Signup and view all the answers

A buffer solution is prepared using a weak acid, HA, and its conjugate base, A-. Which statement accurately describes the buffer's behavior when a small amount of strong acid is added?

The concentration of HA increases, and the pH decreases. (A) Signup and view all the answers

For a sparingly soluble salt MX2, what is the relationship between its solubility (s) and the solubility product constant (Ksp)?

$K_{sp} = 4s^3$ (D) Signup and view all the answers

What is the effect of adding a common ion to a solution of a sparingly soluble salt?

Decreases the solubility of the salt. (C) Signup and view all the answers

Which type of thermodynamic system allows the exchange of energy but not matter with its surroundings?

Closed system (D) Signup and view all the answers

According to the First Law of Thermodynamics, what is the relationship between the change in internal energy (ΔU), heat (q), and work (w) of a system?

ΔU = q + w (A) Signup and view all the answers

For an exothermic reaction, what is the sign of the enthalpy change (ΔH)?

ΔH < 0 (B) Signup and view all the answers

Which of the following statements is true regarding standard enthalpy of formation (ΔHf°)?

Both B and C (B) Signup and view all the answers

According to Hess's Law, how can the standard enthalpy change of reaction (ΔHrxn°) be calculated?

ΔHrxn° = ΣnΔHf°(products) - ΣnΔHf°(reactants) (C) Signup and view all the answers

Which of the following factors generally leads to an increase in entropy?

Increase in the number of gas particles (C) Signup and view all the answers

What does the Second Law of Thermodynamics state about the entropy of an isolated system?

The entropy of an isolated system tends to increase in a spontaneous process. (D) Signup and view all the answers

What is the entropy of a perfect crystal at absolute zero (0 K) according to the Third Law of Thermodynamics?

Zero (B) Signup and view all the answers

How is the Gibbs free energy (G) defined in terms of enthalpy (H), temperature (T), and entropy (S)?

G = H - TS (D) Signup and view all the answers

What condition of Gibbs Free Energy (ΔG) indicates that a reaction is at equilibrium at constant temperature and pressure?

ΔG = 0 (D) Signup and view all the answers

The standard free energy change of a reaction (ΔG°) is related to the equilibrium constant (K) by which equation?

ΔG° = -RTlnK (A) Signup and view all the answers

According to the van't Hoff equation, what is the relationship between the change in the equilibrium constant (K) with temperature (T) and the standard enthalpy change (ΔH°)?

ln(K2/K1) = ΔH°/R (1/T1 - 1/T2) (C) Signup and view all the answers

Which of the following is NOT a state function?

Work (B) Signup and view all the answers

Flashcards

Ionic Equilibrium

Equilibrium between ions and undissociated molecules in solution, especially for weak acids, weak bases, and sparingly soluble salts.

Brønsted-Lowry Theory

Acids donate protons (H+), while bases accept protons.