Q: A solution has a $$pH of 3. $$What is the $$[H^+]$$ concentration?

$$[H^+] = 1 \times 10$$^{-3}$$ \text{ M}$$

Q: Which of the following is the correct expression for the ion product of water ($$K_w) at$$ $$25^A0C$$?

$$K_w = [H^+][OH^-] = 1.0 \times 10$$^{-14}$$

Question 1

Which of the following best defines chemical equilibrium in a reversible reaction?

Accepted Answer

The forward and reverse reaction rates are equal, resulting in constant concentrations of reactants and products.

Question 2

Given the reaction $$aA + bB \rightleftharpoons cC + dD$$, which of the following is the correct expression for the equilibrium constant $$K_c$$?

Accepted Answer

$$K_c = \frac{[C]^c [D]^d}{[A]^a [B]^b}$$

Question 3

If the equilibrium constant $$K$$ for a reaction is multiplied by 2, what happens to the value of $$K$$?

Accepted Answer

The value of $$K is $$squared.

Question 4

Consider the reaction $$N_2(g) + 3H_2(g$$) \rightleftharpoons 2NH_3(g)$$ at equilibrium. If the concentration of NH_3$ is increased, what will happen according to Le Chatelier's Principle?

Accepted Answer

The system will shift to the left, producing more $$N_2$$ and $$H_2.$$

Question 5

Which of the following statements about acids and bases is correct according to the Bronsted-Lowry definition?

Accepted Answer

A base is a substance that accepts a proton ($$H^+).$$

Question 6

Which of the following is the correct relationship between $$pH$$ and $$[H^+]$$?

Accepted Answer

$$pH = -\log_{10} [H^+]$$

Question 7

A solution has a $$pH of 3. $$What is the $$[H^+]$$ concentration?

Accepted Answer

$$[H^+] = 1 	imes 10$$^{-3}$$ 	ext{ M}$$

Question 8

Which of the following will increase the value of the equilibrium constant $$K$$ for an endothermic reaction?

Accepted Answer

Increasing the temperature.

Question 9

Which of the following is a conjugate acid-base pair?

Accepted Answer

$$NH_3$$ and $$NH_4$$^+$$

Question 10

A buffer solution is prepared by mixing $$0.1$$ mol of $$CH_3COOH$$ and $$0.1$$ mol of $$CH_3COONa in$$ $$1 L of $$water. Which equation can be used to calculate the $$pH of $$the buffer?

Accepted Answer

$$pH = pK_a + \log_{10} \left( \frac{[CH_3COONa]}{[CH_3COOH]} \right)$$

Question 11

Which of the following is true about strong acids?

Accepted Answer

They ionize completely in water.

Question 12

If $$K_a$$ for acetic acid is $$1.8 	imes 10$$^{-5}$$, what is the pK_a$?

Accepted Answer

$$pK_a = 4.74$$

Question 13

Which of the following is the correct expression for the ion product of water ($$K_w) at$$ $$25^ A0C$$?

Accepted Answer

$$K_w = [H^+][OH^-] = 1.0 	imes 10$$^{-14}$$

Question 14

A $$0.01 M $$solution of $$HCl is $$prepared. What is the $$pH of $$the solution?

Accepted Answer

$$pH = 2$$

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 weak acid, $$HA$$, has a $$K_a of$$ $$1.0 	imes 10$$^{-6}$$. Which of the following statements is true?

Accepted Answer

The acid ionizes only partially in water.

Question 17

Which of the following is the correct $$pH$$ for a neutral solution at $$25^ A0C$$?

Accepted Answer

$$pH = 7$$

Question 18

Which of the following is the correct $$pOH$$ for a solution with $$[OH^-] = 1 	imes 10$$^{-4}$$ M?

Accepted Answer

$$pOH = 4$$

Question 19

A buffer is made by mixing $$0.2$$ mol $$NH_3$$ and $$0.1$$ mol $$NH_4Cl in$$ $$1 L of $$water. If $$K_b$$ for $$NH_3 is$$ $$1.8 	imes 10$$^{-5}$$, what is the $$pOH$$ of the buffer?

Accepted Answer

$$pOH = pK_b + \log_{10} \left( \frac{[NH_4$^+]}{[NH_3$]} \right)$$

Question 20

Which of the following is the correct relationship between $$pH$$ and $$pOH in $$aqueous solution at $$25^ A0C$$?

Accepted Answer

$$pH + pOH = 14$$

General Chemistry Study Guide: Chemical Equilibrium, Acids and Bases, and Thermodynamics

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