Q: What is the $$pH of a $$solution with $$[H_3O^+] = 2.0 \times 10$$^{-3}$$ M?

$$pH = -\log(2.0 \times 10$$^{-3}$$) = 2.70$$

Q: Calculate the $$[OH^-] in a $$solution where $$[H_3O^+] = 0.00004 M. $$Use $$K_w = 1.0 \times 10$$^{-14}$$.

$$[OH^-] = \dfrac{1.0 \times 10$$^{-14}$$}{0.00004} = 2.5 \times 10$$^{-10}$$ M

Q: Which of the following is the correct expression for the ion-product constant of water?

$$K_w = [H_3O^+] \times [OH^-]$$

Question 1

Which of the following best describes a Bronsted-Lowry acid?

Accepted Answer

A compound that donates a hydrogen ion ($$H^+) in $$solution.

Question 2

What is the $$pH of a $$solution with $$[H_3O^+] = 2.0 	imes 10$$^{-3}$$ M?

Accepted Answer

$$pH = -\log(2.0 	imes 10$$^{-3}$$) = 2.70$$

Question 3

A solution has $$[OH^-] = 7.2 	imes 10$$^{-5}$$ M and $$[H_3O^+] = 1.38 	imes $$10^{-10} M. Is $$the solution acidic, basic, or neutral?

Accepted Answer

Basic, because $$[OH^-] \u003e [H_3O^+]$$

Question 4

Which of the following is a strong acid?

Accepted Answer

$$HNO_3 ($$nitric acid)

Question 5

Calculate the $$[OH^-] in a $$solution where $$[H_3O^+] = 0.00004 M. $$Use $$K_w = 1.0 	imes 10$$^{-14}$$.

Accepted Answer

$$[OH^-] = \dfrac{1.0 	imes 10$$^{-14}$$}{0.00004} = 2.5 	imes 10$$^{-10}$$ M

Question 6

Which of the following reactions is a neutralization reaction?

Accepted Answer

$$HCl(aq) + NaOH(aq) \rightarrow H_2O(l) + NaCl(aq)$$

Question 7

Which of the following pairs forms a buffer solution?

Accepted Answer

$$HF$$ and $$NaF$$

Question 8

If more lactic acid ($$C_3H_6O_3) is $$added to the equilibrium $$C_3H_6O_3 + $$HCO_3$$^- \rightleftharpoons C_3H_5O_3^- + H_2CO_3$$, what will happen according to Le Chatelier’s Principle?

Accepted Answer

The reaction will shift to the right, producing more products.

Question 9

Which statement about weak acids is correct?

Accepted Answer

They only partially dissociate in water.

Question 10

A buffer solution contains equal amounts of acetic acid ($$HC_2H_3O_2) $$and acetate ($$C_2H_3O_2^-). $$What happens when a small amount of $$OH^- is $$added?

Accepted Answer

The $$OH^-$$ reacts with $$HC_2H_3O_2 to $$form water and $$C_2H_3O_2^-.$$

Question 11

Which of the following is the correct expression for the ion-product constant of water?

Accepted Answer

$$K_w = [H_3O^+] 	imes [OH^-]$$

Question 12

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

Accepted Answer

$$HC_2H_3O_2$$ and $$C_2H_3O_2^-$$

Question 13

A sample of seawater has a hydronium ion concentration of $$3.67 	imes 10$$^{-9}$$ M. Is seawater acidic, neutral, or basic?

Accepted Answer

Basic, because $$[H_3O^+] \u003c 1.0 	imes 10$$^{-7}$$ M

Question 14

Which of the following is true about the equilibrium of a weak acid in water?

Accepted Answer

The concentration of reactants is usually higher than products.

Question 15

Which of the following is a polyprotic acid?

Accepted Answer

$$H_2SO_4$$

Question 16

A patient with emphysema cannot breathe out $$CO_2$$ efficiently. What effect does this have on blood pH?

Accepted Answer

Blood pH decreases, causing acidosis.

Question 17

Which of the following is a strong base?

Accepted Answer

$$Ba(OH)_2$$

Question 18

Beer has a $$pH of 5.0. Is $$beer acidic, basic, or neutral?

Accepted Answer

Acidic, because $$pH \u003c 7$$

Question 19

Which of the following best explains why buffers are important in human physiology?

Accepted Answer

Buffers maintain a stable pH by neutralizing small amounts of added acid or base.

Chapter 10: Acids, Bases, and Equilibrium – Study Notes

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