Chapter 15

Question 1

Arrhenius Definition

Answer 1

• Acid: A substance that produces H⁺ ions in aqueous solution.
• Base: A substance that produces OH^- ions in aqueous solution.

Question 2

Brønsted–Lowry definition

Answer 2

• Acid: proton (H⁺ ion) donor (becoming a conjugate base).
• Base: proton (H+ ion) acceptor (becoming a conjugate acid).

Question 3

Amphoteric

Answer 3

A substance that can act as either an acid or a base.

Question 4

Conjugate Acid-Base Pair

Answer 4

Two substances related to each other by the transfer of a proton.

Question 5

Conjugate Acid

Answer 5

Any base to which a proton has been added.

Question 6

Strong Acid

Answer 6

completely ionizes in solution.

Example: HCl

Question 7

Weak Acid

Answer 7

Only partly ionizes in solution.

• The equilibrium concentration of a weak acid increases with increasing
  initial concentration of the acid.
• The percent ionization of a weak acid decreases with increasing concentration
  of the acid.

Question 8

Triprotic

Answer 8

An acid that that contains three ionizable protons.

Question 9

Acid-Ionization Constant

Answer 9

The equilibrium constant for the ionization reaction of a weak acid.

Question 10

Autoionization

Answer 10

The process by which water acts as an acid and a
base with itself.

Question 11

Ion Product Constant for Water (Kw)

Answer 11

The equilibrium constant for the autoionization of water.

Kw = [H3O⁺][OH^-] = [H+][OH^-]

• Neutral solution contains [H₃O⁺]=[OH^-]=1.0x10^-7
• Acidic solution contains [H₃O⁺]>[OH^-]
• Basic solution contains [OH^-]>[H₃O⁺]

Question 12

pH Equation

Answer 12

pH=-log[H3O+]

Question 13

pOH Equation

Answer 13

pOH=-log[OH^-]

Question 14

pK_a

Answer 14

pK_a= -log(K_a)

• The smaller the pK_a, the stronger the acid.

Question 15

[H₃O⁺] and pH of Strong Acids

Answer 15

The concentration of [H₃O⁺] in a strong acid solution is equal to the concentration of the strong
acid.

Question 16

[H_³O⁺] and pH of Weak Acids

Answer 16

• Concentration of H₃O⁺is not equal to the concentration of the weak acid.
• The equilibrium concentration of a weak acid increases with increasing
  initial concentration of the acid.
• The percent ionization of a weak acid decreases with increasing concentration
  of the acid.

Question 17

Percent Ionization of a week acid

Answer 17

The ratio of the ionized acid concentration to the initial acid concentration, multiplied
by 100%:

Question 18

Strong Bases

Answer 18

A base that completely dissociates in solution

Question 19

Weak Base

Answer 19

A base that only partly ionizes in solution.

Question 20

Base Ionization Constant (K_b)

Answer 20

The equilibrium constant for the ionization reaction of a weak base; used to compare the relative strengths of weak bases.