Chapter 16: Reactions Between Acids and Bases Flashcards

1
Q

titration: a procedure for the determination of the … of one substance by the addition of a measured amount of a second substance

A

quantity

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2
Q

analyte: substance whose concentration is

A

being determined

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3
Q

titrant is the substance added to

A

react with the analyte

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4
Q

(basic procedure for acid-base titrations) 1) a known volume of an acid of … is placed in a flask

A

unknown []

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5
Q

(basic procedure for acid-base titrations) 2) an indicator solution that changes color in a particular … is added to the acid

A

pH range

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6
Q

(basic procedure for acid-base titrations) 3) a standard solution of base is added until a … occurs, called the …

A

color change; endpoint

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7
Q

a titration curve is a graph of the pH of a solution as a function of the

A

amount of titrant that is added

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8
Q

equivalence point: point in the titration when exactly one mole of base has been added for

A

each mole of acid present in the sample

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9
Q

inflection point: point at which pH

A

changes most rapidly

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10
Q

the titration of a strong acid with a strong base shows a … in pH at the equivalence point

A

sharp change

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11
Q

the titration .., …, and … all influence the equivalence point volume

A

stoichiometry, concentrations, volumes

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12
Q

buffers are solutions that … when either OH- or H+ ions are added

A

resist changes in pH

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13
Q

strong acids and bases cannot be used as

A

buffers

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14
Q

buffered solutions contain either: a weak … and its … or a weak … and its …

A

acid; salt; base; salt

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15
Q

(buffers) keq for neutralization is … meaning that Keq is … and the reaction goes essentially to ..

A

1/Ka; large; completion

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16
Q

pH of buffer solutions is generally limited to the vicinity of the

A

pKa for the acid

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17
Q

buffers are most effective in the range of

A

pKa +- 1

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18
Q

to make an effective buffer, the concentrations of the weak acid and its conjugate base must be at least

A

100 times the Ka or Kb

19
Q

most pH buffers are made from solutions with concentrations that range from

A

.1 to 1.0 M

20
Q

concentrated buffers are generally more … than dilute buffers

21
Q

the effectiveness of a buffer is measured by

A

buffer capacity

22
Q

buffer capacity= the amount of strong acid or base needed to change the pH of

A

one liter of buffer by one unit

23
Q

acid/salt buffering pairs: salt will contain the …., and the cation of a

A

anion of the acid; strong base

24
Q

base/salt buffering pairs: the salt will contain the cation of the …, and the anion of a …

A

base; strong acid

25
the amount of base needed to neutralize an acid depends only on the amount of
acid present, not whether it is strong or weak
26
the titration curves for all the acids are indistinguishable beyond the equivalence point since
excess OH- determines the pH of solution
27
the pH halfway to the equivalence point in the titration of a weak acid is equal to the
pKa
28
the pH at the equivalence point is not 7.0 unless
both the acid and the base are strong
29
indicator: substance that changes ... to signal the end of a titration
color
30
an indicator should be chosen such that the ... and ... are the same
end point; equivalence point
31
indicators should have the following attributes: change color ... as a function of pH color change should be ... should not ... the system (should not consume a large amount of titrant/reactant)
abruptly; visible; perturb
32
indicators are ... in which the acid is a different color from the conjugate base
weak acid-base conjugate pairs
33
HIn + H2O H3O+ + In- | Kin=
[H3O+][In-]/[HIn]
34
if pH < pKin, most of the indicator is in the .. form | if pH > pKin, most of the indicator is in the ... form
acid; base
35
an indicator should be chosen to change color at or just beyond the
equivalence point
36
polyprotic acids provide more than one ... when they ionize
proton
37
successive ionization constants for polyprotic acids get smaller often by a factor of
more than 1000
38
to estimate the pH of a polyprotic acid, treat as if you had a
mixture of weak acids
39
amphoteric species have the properties of both
acids and bases
40
to estimate the pH of a solution of an amphoteric substance, compare ... and .... if Ka > Kb, the solution is .... if Kb > Ka, the solution is ...
Ka; Kb; acidic; basic
41
the solubility of a salt of a weak acid increases with the addition of
acid
42
solubility of a precipitate increases in the presence of a
complexing agent
43
additive reactions --> ... Ks to find overall equilibrium constants
multiply