Chapter 12: Introduction to Acids and Bases

Question 1

acids tend to

Answer 1

taste sour, react with active metals to produce H2 (g), and turn litmus red

Question 2

bases tend to

Answer 2

taste bitter, produce solutions that feel slippery, and turn litmus blue

Question 3

acid/base indicators

Answer 3

chemical compounds that change color in acidic, basic, or neutral environments

Question 4

both acids and bases dissociate to form ions in aqueous solution, therefore they are

Answer 4

electrolytes

Question 5

acids and bases that completely ionize/dissociate (100%) are

Answer 5

strong

Question 6

acids and bases that do not completely ionize in aqueous solution are

Answer 6

weak

Question 7

Arrhenius definition (acid)

Answer 7

an acid is a hydrogen-containing substance that dissociates to produce hydrogen ions (H+), which are typically present as H3O+ in water

acidic solutions have a higher [H3O+]

Question 8

Arrhenius definition (base)

Answer 8

a base is a substance that dissociates to produce hydroxide ions (OH-) in aqueous solution

basic solutions have a higher [OH-]

Question 9

neutral solutions have

Answer 9

[H3O+] = [OH-]

Question 10

H2O can function as

Answer 10

both an acid and a base; water is essentially a non-electrolyte, but there is a small amount of dissociation

allows for the autoionization of water

Question 11

polyprotic acids

Answer 11

can release more than one H+ into aqueous solution

Question 12

acids that can only release one proton into solution are

Answer 12

monoprotic acids (e.g., hydrochloric acid, hydrobromic acid, and nitric acid)

Question 13

diprotic acids such as sulfuric acid and carbonic acid can release

Answer 13

two protons

Question 14

triprotic acids such as phosphoric acid can release

Answer 14

three protons

Question 15

Bronsted-Lowry definition (acid)

Answer 15

an acid is a proton donor

Question 16

Bronsted-Lowry definition (base)

Answer 16

a base is a proton acceptor

Question 17

the ionization of weak acids is an example of an

Answer 17

equilibrium reaction

Question 18

when describing an acid-base equilibrium, we refer to the acid and base on the right-hand side of the chemical equation as the

Answer 18

conjugate acid and conjugate base

Question 19

the conjugate acid is formed when

Answer 19

a base gains a proton (H+); it’s what forms when a base accepts a proton

Question 20

the conjugate base is formed when

Answer 20

an acid loses a proton; it is what remains of the acid after it has donated a proton

Question 21

the conjugates of weak acids are

Answer 21

basic; they can act as a weak base and accept protons from water and increase the OH- concentration

Question 22

in acid-base neutralization reactions, an acid and a base combine to produce

Answer 22

water and an ionic compound (salt); the formation of water is the driving force for the neutralization reaction

double-displacement reaction

Question 23

acids react with pure metals to produce

Answer 23

hydrogen gas (single-displacement reaction)

precious metals (silver, gold, and platinum) do not react with acid

Question 24

nonmetal oxides

Answer 24

compounds that contain a nonmetal covalently bonded to one or more oxygen atoms; typically react with water to form acidic solutions

Question 25

metal oxides

Answer 25

compounds that consist of a metal element chemically bonded to oxygen; reacts with water to form basic solutions

Question 26

acids react with carbonates to produce

Answer 26

water, carbon dioxide, and a salt

Question 27

autoionization of water

Answer 27

the process in which water molecules spontaneously dissociate into hydronium ions and hydroxide ions | a water molecule donates a proton to another water molecule to form ions

Question 28

the autoionization of water yields

Answer 28

the same number of hydronium and hydroxide ions; [H3O+] and [OH-] = 1.0 x 10^-7 M

Question 29

the equilibrium constant expression for the autoionization of water is

Answer 29

Kw; Kw = [H3O+][OH-] = 1 x 10^-14 M at 25 C

Question 30

a common way to express acidity and basicity is

Answer 30

pH

Question 31

pH is a measure of

Answer 31

[H3O+] aka [H+]; pH = -log[H3O+] | -log[1.00 x 10^-7] = 7 (neutral)

Question 32

pOH =

Answer 32

-log[OH-]; since [OH-] = 1.0 x 10^-7 M, pOH = 7 (neutral)

Question 33

pH + pOH =

Answer 33

14

Question 34

if the pH decreases, the [H3O+]

Answer 34

increases; the solution is more acidic than neutral water | remember: pH is the negative logarithm of the [H3O+]

Question 35

pH < 7.00

Answer 35

the solution is acidic

Question 36

pH = 7.00

Answer 36

the solution is neutral

Question 37

pH > 7.00

Answer 37

the solution is basic

Question 38

a change of 1 pH represents

Answer 38

a tenfold change in [H3O+]; a decrease in pH by 1 unit increases [H3O+] by a factor of 10 & an increase in pH by 1 unit decreases [H3O+] by a factor of 10

Question 39

because strong acids dissociate completely, the acid molecules break apart to form

Answer 39

hydronium ions and anions (conjugate base); thus, [strong acid] is the same as [H3O+]

Question 40

titration

Answer 40

an analytical technique used to precisely determine the concentration of an acid or base by measuring the volume required for a neutralization to occur | used to determine the molarity of an unknown acid or base

Question 41

buffer

Answer 41

a solution containing a mixture of acidic and basic components that resists changes in pH; adding acid or base in a buffered solution causes a smaller pH change

Question 42

two common combinations of buffers are

Answer 42

a mixture of a weak acid and its conjugate base & a weak base and its conjugate acid

Question 43

the pH of a buffer solution depends on

Answer 43

the relative amounts of the acid and base components

Question 44

the weaker the acid,

Answer 44

the stronger the conjugate base | weak acids leave a conjugate base w/ a greater ability to accept protons

Question 45

the stronger the acid,

Answer 45

the weaker the conjugate base

Question 46

there is no reverse reaction with a strong acid because

Answer 46

the strong acid completely dissociates, going all the way to the right side of the reaction; dissociation is essentially irreversible because of the strong tendency to donate a proton

Question 47

the salt of a strong acid forms a

Answer 47

neutral solution because the conjugate base is very weak and does not interact with water in a way that would alter the pH

Question 48

the salt of a weak acid forms a

Answer 48

basic solution because the conjugate base is strong enough to react with water and increase the [OH-], thus increasing the pH

Question 49

since the salt of a weak acid is basic, a neutralization reaction can take place with

Answer 49

an acid; the conjugate base of the weak acid (present in the salt) can neutralize the H⁺ ions from the acid, reforming the weak acid in hydrolysis

Question 50

hydrolysis

Answer 50

a chemical reaction in which a substance reacts with water to produce either H+ or OH- ions, affecting the pH (acidic, basic, or neutral hydrolysis)