Acids and Bases

Question 1

Defined an acid as a species that donates H+ (protons) in an aqueous sol’n and a base as a species that produces OH- (hydroxide ions) in an aqueous sol’n

Answer 1

Arrhenius

Question 2

any species that donates protons

*Do not necessarily have to dissociate into H+ in aqueous sol’n

Answer 2

Bronsted-Lowry acid

Question 3

any species that accepts protons
*Do not necessarily have to dissociate to form OH- in aqueous sol’n
(Ex: NH3 and Cl-)

Answer 3

Bronsted-Lowry base

Question 4

Defines a ______ as an electron-pair acceptor

Answer 4

Lewis acid

Question 5

defines a _____ as an electron-pair donor

Answer 5

lewis base

Question 6

Bronsted-Lowry acids and bases always occur in pairs, called _______. The two members are related by the transfer of a proton

Answer 6

conjugate acid-base pairs

Question 7

The stronger the acid, the _______ its conjugate base

Answer 7

weaker

Question 8

the weaker the acid, the ________ its conjugate base

Answer 8

stronger

Question 9

H2O can act as either a ________ or a _____ with other species or with itself
H2O + H2) —-> H3O+ + OH-

Answer 9

proton donor or acceptor

Question 10

Constant that describes _______, or acting as a proton donor/acceptor toward itself

Answer 10

Autoionization: Kw

Question 11

Equation: Kw (Autoionization constant)

Answer 11

Keq = Kw = [H3O+][OH-]

Note: Kw for water = 110^-14

Question 12

measures hydrogen ion (proton) concentration

pX = -log(X) where [H+] is its molarity and the logarithm is of base 10

Answer 12

pH

Question 13

Equation: pH

Answer 13

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

Question 14

The power to which 10 would be raised to obtain the number x

Answer 14

Log(x)

i.e. [H+] = 1 * 10^-3 then pH = 3

Question 15

have a pH less than 7
relative excess of H+ ions
Ex: Lemon juice, gastric juice

Answer 15

acidic sol’n

Question 16

pH greater than 7
relative excess of OH- ions
Ex: baking soda, bleach, ammonia

Answer 16

basic sol’n

Question 17

pH = 7

Ex: water

Answer 17

neutral sol’n

Question 18

completely dissociate into their component ions in aqueous sol’n

Answer 18

strong acid and bases

Question 19

Examples of this include: HClO4, HNO3, H2SO4, HCl, HBr, HI

Answer 19

strong acids

Question 20

Examples of this include: NaOH, KOH, soluble hydroxides of Group IA and IIA metals

Answer 20

strong bases

Question 21

substances that do not ionize completely (only partially)

weak electrolytes

Answer 21

weak acids and bases

Question 22

equilibrium constant for acid ionization
acid dissociation constant
measure of the degree to which an acid dissociates
smaller for weaker acids

Answer 22

Ka

Question 23

equilibrium constant for base ionization

Answer 23

Kb

Question 24

the smaller the _____, the weaker the acid (i.e. must smaller than 1)

Answer 24

Ka

Question 25

Equation: Ka

Answer 25

Ka = [H+][A-] / [HA] | Note: [A-] = conjugate base; [HA] = weak acid

Question 26

Strategy: Calculate the pH for sol'ns of weak acids

Answer 26

1. ID start concentration for weak acid (reactant) and H+ and A- (product) 2. Calculate change in concentration 3. ID end concentration of weak acid (reactant) and H+ and A-

Question 27

The concentratino of teh weak acid at equilibrium = it's initial concentration minus the _______

Answer 27

amount dissociated

Question 28

The concentration of [H+] dissociated from a weak acid equals ______

Answer 28

amount of conjugate base formed

Question 29

the addition of a sol'n of known concentration and volume to another sol'n to determine its unknown concentrations involved the addition of a sol'n to determine its concentration

Answer 29

titrations

Question 30

add base of precisely known concentration drop by drop to an acid solution until the numbero f moles of base added equals the number of moles of acid initially present

Answer 30

acid-base titration

Question 31

point at which the number of moles of base added equals the number of moles of acid initially present in an acid-base titration

Answer 31

equivalence point

Question 32

Equation: Acid-Base titration at equilibrium point

Answer 32

Va * Ma = Vb * Mb Note: Va = initial volume of acid solution; Ma = acid's molarity (trying to determine); Vb = volume of base added; Mb = molarity of the base (known precisely before)

Question 33

T/F: The equivalence point in an acid-base titration must occur at pH 7

Answer 33

False

Question 34

Titrations between a strong acid and strong base have an equivalence point at pH =

Answer 34

7

Question 35

titration between a weak acid and a strong base has an equivalence point at pH ______

Answer 35

>7