Acids and Bases

Question 1

dissociate to produce an excess of hydrogen ions (H+) in solution; have H at beginning of formula

Answer 1

Arrhenius acid

Question 2

dissociate to produce an excess of hydroxide ions (OH-) in solution; have OH at end of formula

Answer 2

Arrhenius base

Question 3

species that can donate H atoms

Answer 3

Bronsted-Lowry acid

Question 4

species that accept H atoms

Answer 4

Bronsted-Lowry base

Question 5

electron pair acceptors

Answer 5

Lewis acid

Question 6

electron pair donors

Answer 6

Lewis base

Question 7

species that can behave as an acid (in a basic environment) or a base (in an acidic environment)

Answer 7

amphoteric

Question 8

amphoteric species that donate or accept a proton (H+ ion), behaving as a Bronsted-Lowry acid or base

Answer 8

amphiprotic

Question 9

amphiprotic example:

Answer 9

water- can accept a H+ to become H3O+ or lose a H+ to become OH-

Question 10

process where an amphoteric compound reacts with itself (like water); one water molecule can donate a hydrogen atom to another water molecule to produce the hydronium ion (H3O+) and the hydroxide ion (OH-)

Answer 10

autoionization

Question 11

water dissociation constant (K(w))

Answer 11

K(w) = [H3O+] [OH-] = 10^-14

true at 298 K, only affected by changes in temperature

Question 12

logarithmic scale for the concentration of hydrogen (hydronium) ions

Answer 12

pH

Question 13

pH

Answer 13

pH = -log [H+] = log 1/[H+]

Question 14

logarithmic scale for the concentration of hydroxide ions

Answer 14

pOH

Question 15

pOH

Answer 15

pOH = -log [OH-] = log 1/[OH-]

Question 16

pH + pOH = __

Answer 16

pH + pOH = 14

in aqueous solutions at 298 K

Question 17

completely dissociate into their component ions in aqueous solution

Answer 17

strong acids and bases

Question 18

do not completely dissociate in solution and have corresponding dissociation constants (K(a) and K(b))

Answer 18

weak acids and bases

Question 19

acid dissociation constant (K(a))

Answer 19

K(a) = [H3O+] [A-] / [HA]

Question 20

base dissociation constant (K(b))

Answer 20

K(b) = [OH-] [B+] / [BOH]

Question 21

acid formed when a base gains a proton

Answer 21

conjugate acid

Question 22

base formed when an acid loses a proton

Answer 22

conjugate base

Question 23

when an acid and base react with each other to form a salt and sometimes water

Answer 23

neutralization reaction

Question 24

defined as one mole of the species of interest

Answer 24

equivalent

Question 25

equal to one mole of H+ (H3O+) ions

Answer 25

acid equivalent

Question 26

equal to one mole of OH- ions

Answer 26

base equivalent

Question 27

the concentration of acid or base equivalents in solution

Answer 27

normality

Question 28

acids and bases that can donate or accept multiple electrons/protons (by the Bronsted-Lowry definition)

Answer 28

polyvalent/polyprotic

Question 29

used to determine the concentration of known reactant in a solution; performed by adding small volumes of a solution of known concentration (titrant) to a known volume of a solution of unknown concentration (titrand) until completion of the reaction is achieved at the equivalence point

Answer 29

titration

Question 30

titration:

has a known concentration and is added slowly to the titrand to reach the equivalence point

Answer 30

titrant

Question 31

titration:

has an unknown concentration but a known volume

Answer 31

titrand

Question 32

titration:
midpoint of the buffering region, in which half of the titrant has been protonated (or deprotonated); thus, [HA] = [A-] and a buffer is formed

Answer 32

half-equivalence point

Question 33

titration:
is indicated by the steepest slope in a titration curve; it is reached when the number of acid equivalents in the original solution equals the number of base equivalents added, or vice-versa

Answer 33

equivalence point

Question 34

equivalence point equation:

Answer 34

N(A) V(A) = N(B) V(B)

where:
N(A) and N(B) = acid and base normalities
V(A) and V(B) = volumes of acid and base solutions

Question 35

have equivalence points at pH = 7

Answer 35

strong acid + strong base titrations

Question 36

have equivalence points at pH > 7

Answer 36

weak acid + strong base titrations

Question 37

have equivalence points at pH < 7

Answer 37

weak base + strong acid titrations

Question 38

can have equivalence points above or below 7, depending on the relative strength of the acid and base

Answer 38

weak acid + weak base titrations

Question 39

titration:
weak acids or bases that display different colors in their protonated and deprotonated forms; ____ chosen for a titration should have a pK(a) close to the pH of the expected equivalence point

Answer 39

indicators

Question 40

titration:

when the indicator reaches its final color in a titration

Answer 40

endpoint

Question 41

titration:

observed in polyvalent/polyprotic acid and base titrations

Answer 41

multiple buffering regions and equivalence points

Question 42

consists of a weak acid and its conjugate salt or a weak base and its conjugate salt; they resist large fluctuations in pH; e.g. a solution of acetic acid (CH3COOH) and its salt, sodium acetate (CH3COO- Na+), or a solution of ammonia (NH3) and its salt, ammonium chloride (NH4+ Cl-)

Answer 42

buffer solutions

Question 43

refers to the ability of a buffer to resist changes in pH; maximal ____ is seen within 1 pH point of the pK(a) of the acid in the buffer solution

Answer 43

buffering capacity

Question 44

quantifies the relationship between pH and pK(a) for weak acids and between pOH and pK(b) for weak bases; when a solution is optimally buffered, pH = pK(a) and pOH = pK(b)

Answer 44

Henderson-Hasselbach equation

Question 45

Henderson-Hasselbach equation

Answer 45

pH = pK(a) + log [A-] / [HA]

pOH = pK(b) + log [B+] / [BOH]

where:
[A-} = concentration of the conjugate base
[HA] = concentration of the weak acid
[B+] = concentration of the conjugate acid
[BOH] = concentration of the weak base