Q: Which equilibrium constant represents a reaction that favors the reactants to the greatest extent?

$$K_{eq} = 1.0 \times 10$$^{-10}$$

Question 1

A mixture of SO$$_2$$, O$$_2$$, and SO$$_3 at a $$certain temperature contains 0.180 M SO$$_2$$ and 0.0753 M O$$_2. $$The equilibrium constant $$K_c$$ for the reaction $$2SO_2(g) + O_2$(g) \rightarrow 2SO_3(g) is 429. $$What is the equilibrium concentration of SO$$_3$$?

Accepted Answer

1.07 M

Question 2

The pH of a solution is 5.00 at 25°C. Which of the following is true about the solution?

Accepted Answer

The [H$$_3O$^+$$] is 1.0 × 10$$^{-5} M.$$

Question 3

Which of the following pairs of substances are an acid and its conjugate base?

Accepted Answer

H$$_2CO$_3 / $$HCO$$_3^-$$

Question 4

Consider the equilibrium: AgI (s) ⇌ Ag$$^+ (aq) + I$^- (aq$$), $$K_c = 1.3 	imes 10$$^{-8}$$ at 273 K. Which diagram best represents the reaction mixture at equilibrium?

Accepted Answer

Flask 2

Question 5

Which equilibrium constant represents a reaction that favors the reactants to the greatest extent?

Accepted Answer

$$K_{eq} = 1.0 	imes 10$$^{-10}$$

Question 6

Solution A: 0.10 M HNO$$_2$$ with $$K_a = 4.5 	imes 10$$^{-4}$$ at 25°C. Solution B: 0.10 M H_2$S with K_a = 9.0$$ 	imes $$10^{-8} at 25$$°C. Which statement is true?

Accepted Answer

Solution A is more acidic than solution B.

Question 7

Consider the equilibrium: $$2H_2S(g) + O_2$(g) \rightleftharpoons 2H_2O(g) + 2S(s)$$, $$\Delta H = +130 kJ. $$Which of the following scenarios will favor the forward reaction (shift the equilibrium to the right)?

Accepted Answer

Increasing the temperature.

Question 8

What is the concentration of the aqueous OH$$^-$$ ion given that the concentration of the aqueous H$$_3O$^+$$ ion is 1.3 × 10$$^{-5} M at 25$$°C?

Accepted Answer

$$7.7 	imes 10$$^{-10}$$ M

Question 9

What is the acid dissociation expression for hydrofluoric acid (HF) reacting with water?

Accepted Answer

$$K_a = \frac{[H^+][F^-]}{[HF]}$$

Question 10

A buffer solution is made by mixing equal concentrations of acetic acid and sodium acetate. What will happen to the pH if a small amount of HCl is added?

Accepted Answer

The pH will decrease slightly.

Question 11

Which of the following is a correct statement about the relationship between $$K_a$$ and acid strength?

Accepted Answer

A larger $$K_a$$ value means a stronger acid.

Question 12

Which of the following changes will increase the solubility of AgCl in water?

Accepted Answer

Adding NH$$_3 to $$the solution.

Question 13

A solution has a pOH of 4.00. What is the concentration of OH$$^-$$ ions?

Accepted Answer

$$1.0 	imes 10$$^{-4}$$ M

Question 14

Which of the following is true for a reaction at equilibrium?

Accepted Answer

The rates of the forward and reverse reactions are equal.

Question 15

Which of the following will NOT affect the position of equilibrium in a chemical reaction?

Accepted Answer

Adding a catalyst.

Question 16

A solution is prepared by dissolving 0.10 mol of acetic acid (CH$$_3$$COOH) and 0.10 mol of sodium acetate (CH$$_3$$COONa) in 1.0 L of water. What is the pH of the solution if $$K_a$$ for acetic acid is $$1.8 	imes 10$$^{-5}$$?

Accepted Answer

pH = 4.74

Question 17

Which of the following is a correct expression for the equilibrium constant $$K_c$$ for the reaction $$N_2(g) + 3H_2(g$$) \rightleftharpoons 2NH_3(g)$$?

Accepted Answer

$$K_c = \frac{[NH_3$]^2}{[N_2$][H_2$]^3}$$

General Chemistry I – Chemical Equilibrium and Acid-Base Concepts (Unit 4 Study Guide)

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