Q: Arrange the following acids by increasing acid strength: $$K_a = 5.7 \times 10$$^{-7}$$, K_a = 3.3$$ \times $$10^{-5}$$, $$K_a = 1.2 \times 10$$^{-3}$$.

$$5.7 \times 10$$^{-7}$$ \u003c 3.3 \times 10$$^{-5}$$ \u003c 1.2 \times 10$$^{-3}$$

Q: A solution has $$[OH^-] = 3.2 \times 10$$^{-10}$$ \text{ M}. $$What is $$[H_3O^+] in $$this solution at 25°C?

$$[H_3O^+] = \frac{1.0 \times 10$$^{-14}$$}{3.2 \times 10$$^{-10}$$} = 3.1 \times 10$$^{-5}$$ \text{ M}$$

Q: Calculate the pH of a blood sample with $$[H_3O^+] = 5.75 \times 10$$^{-8}$$ \text{ M}.$$

$$pH = -\log(5.75 \times 10$$^{-8}$$) = 7.24$$

Q: A 15.6 mL sample of KOH is neutralized by 32.0 mL of 0.385 M HCl. What is the molarity of the KOH solution?

$$M_{KOH} = \frac{M_{HCl} \times V_{HCl}}{V_{KOH}} = \frac{0.385 \times 32.0}{15.6} = 0.79 \text{ M}$$

Question 1

Which of the following statements best describes a Brønsted-Lowry acid?

Accepted Answer

A substance that donates a proton (H+)

Question 2

Which compound acts as the Brønsted-Lowry base in the following reaction? $$\mathrm{CH_3CO_2H(aq) + H_2O(l) \rightarrow CH_3CO_2^-(aq) + H_3O^+(aq)}$$

Accepted Answer

H$$_2O$$

Question 3

What is the conjugate base of H$$_3PO$_4$$?

Accepted Answer

H$$_2PO$_4^-$$

Question 4

Which of the following is a diprotic acid?

Accepted Answer

H$$_2CO$_3$$

Question 5

Which equation correctly represents the dissociation of hydrofluoric acid (HF) in water?

Accepted Answer

$$\mathrm{HF(aq) + H_2O(l) \rightleftharpoons H_3O^+(aq) + F^-(aq)}$$

Question 6

Arrange the following acids by increasing acid strength: $$K_a = 5.7 	imes 10$$^{-7}$$, K_a = 3.3$$ 	imes $$10^{-5}$$, $$K_a = 1.2 	imes 10$$^{-3}$$.

Accepted Answer

$$5.7 	imes 10$$^{-7}$$ \u003c 3.3 	imes 10$$^{-5}$$ \u003c 1.2 	imes 10$$^{-3}$$

Question 7

A solution has $$[OH^-] = 3.2 	imes 10$$^{-10}$$ 	ext{ M}. $$What is $$[H_3O^+] in $$this solution at 25°C?

Accepted Answer

$$[H_3O^+] = \frac{1.0 	imes 10$$^{-14}$$}{3.2 	imes 10$$^{-10}$$} = 3.1 	imes 10$$^{-5}$$ 	ext{ M}$$

Question 8

Calculate the pH of a blood sample with $$[H_3O^+] = 5.75 	imes 10$$^{-8}$$ 	ext{ M}.$$

Accepted Answer

$$pH = -\log(5.75 	imes 10$$^{-8}$$) = 7.24$$

Question 9

Which of the following pairs could form a buffer solution?

Accepted Answer

HPO$$_4$$^{2-}$$ and PO$$_$$4^{3-}$$

Question 10

Which description best characterizes an aqueous solution with $$[H_3O^+] = 8.8 	imes 10$$^{-7}$$ 	ext{ M}$$?

Accepted Answer

slightly acidic

Question 11

Write the balanced equation for the neutralization reaction between HBr and NaOH.

Accepted Answer

$$\mathrm{HBr(aq) + NaOH(aq) \rightarrow NaBr(aq) + H_2O(l)}$$

Question 12

A 15.6 mL sample of KOH is neutralized by 32.0 mL of 0.385 M HCl. What is the molarity of the KOH solution?

Accepted Answer

$$M_{KOH} = \frac{M_{HCl} 	imes V_{HCl}}{V_{KOH}} = \frac{0.385 	imes 32.0}{15.6} = 0.79 	ext{ M}$$

Question 13

Which of the following statements about strong acids is correct?

Accepted Answer

Strong acids dissociate completely in water.

Question 14

Which of the following is NOT a strong base?

Accepted Answer

NH$$_3$$

Question 15

What is the role of a buffer in a biological system?

Accepted Answer

To maintain pH by neutralizing small amounts of added acid or base

Question 16

Which of the following best describes the relationship between acid strength and conjugate base strength?

Accepted Answer

The stronger the acid, the weaker its conjugate base.

Question 17

Which equation represents the water dissociation constant ($$K_w) at 25$$°C?

Accepted Answer

$$K_w = [H_3O^+][OH^-] = 1.0 	imes 10$$^{-14}$$

Question 18

Which of the following is a real-life example of a buffer system in the human body?

Accepted Answer

Carbonic acid/bicarbonate system in blood

Chapter 12: Acids and Bases – Study Notes

Guida di studio - Domande di pratica

Study guide - Flashcard