London N616 Chem 8/31 Exam 1--Fall 2011

Front 1

why are pH & acid base balance important

Back 1

[H+] in body is tightly regulated. Provides conditions for optimal intracellular function esp:
-intracellular trapping of metabolite intermediates is maximized at intracellular pH of neutrality;
-activity of proteins (enzymes) is optimized b/c net charge kept constant

Front 2

name the three definitions of acid & bases in aqueous solutions

Back 2

Arrhenius
Bronsted-Lowry
Lewis

Front 3

What is the Arrhenius definition of acid/base

Back 3

Arrhenius:
acid: H+ or H3O+ producer in water (HCl, HNO3)

think Arr H enius = H+ or OH-
base: OH- producer in water (NaOH, LiOH)

Front 4

what is the Bronsted-Lowry definition of acid/base

Back 4

Bronsted-Lowry

Acid: proton (H+) donor
Base: proton acceptor

think brOnsted-lOwry = proton

Front 5

what is the Lewis definition of acid base

Back 5

Lewis

acid: electron-pair acceptor
base: electron pair donor

think l E wis = electron

Front 6

In the Bronsted-Lowry definition what do acids donate? what do bases accept

Back 6

acids donate protons

bases accept protons

Front 7

an acid becomes a ____ after the donation of its proton

Back 7

base

Front 8

if acids or bases are 100% ionized in solution, they are said to be this

Back 8

strong acids or strong bases

Front 9

How do you recognize conjugate acid-base pairs

Back 9

conjugate acid base pairs differ by exactly 1 H ion;

the charge on the conjugate acid is always one greater than the charge on the conjugate base

Front 10

according to the B/L theory, acids donate protons--otherwise known as

Back 10

H+

Front 11

according to the B/L theory, the solvent (eg H20) may act as a ___________ or ____ acceptor

Back 11

proton or H+

Front 12

an acid becomes a ____after the donation of its proton, since the process may be reversed

Back 12

base

Front 13

a base becomes an _______after accepting a proton or H+, since the process may be reversed

Back 13

acid

Front 14

In the equation:

HCl ---> H+ + Cl-

HCl is an acid

if HCl gave away its H+, that leaves Cl-, in the reverse direction, Cl- becomes the _____ base of HCl because it takes a H+; conversely HCl is the ________acid of Cl-

Back 14

conjugate; conjugate

Front 15

the higher the Ka (the equilibrium constant for dissociation of a weak acid), the __________the tendency to dissociate a proton

Back 15

greater

Front 16

H30+ is the __________ion

Back 16

hydronium

Front 17

the hydronium ion is

Back 17

H30+

Front 18

when you have an acid (Hx) and base (x-) that differ in the presence or absence of H+, they are called

Back 18

conjugate acid/base pairs

Front 19

every acid has a ______base formed by removing H+

(X- is the conjugate base of HX)

Back 19

conjugate

Front 20

every base has a _________acid by adding H+

(HX is the conjugate acid of X-)

Back 20

conjugate

Front 21

stronger the acid, the ______ the conjugate base

Back 21

weaker

Front 22

the stronger the base, the ______the conjugate acid

Back 22

weaker

Front 23

in the reaction,

HA + B ---> <--- A- + HB +
which are the conjugate pairs & why

Back 23

the two pairs of protonated & deprotonated substances are HA & A-, and HB+ & B are called conjugate acid-base pairs

when an acid gives away a proton, it always gives it to a base, so when an acid gives away its H+ to a base, the acid is converted into its conjugate base

Front 24

what is the definition of a strong acid

Back 24

a strong acid is a proton-donating compound which is completely dissociated in water to produce only H30+ (aq) ions & accompanying anions
eg: HCl, HNO3, H2SO4

Front 25

what is the definition of a strong base

Back 25

a strong base is a compound which is completely dissociated in water to produce only OH-(aq) & accompanying cations

eg: NaOH, Ca(OH)2, KOH

Front 26

a hydroxyl ion is

Back 26

OH-

Front 27

a hydrogen ion is

Back 27

H+

Front 28

what is a neutralization reaction

HCl + NaOH ---> H20 + NaCl

Back 28

a neutralization reaction is a chemical reaction between an acid & base, that yields a salt & water

Front 29

a neutralization reaction is a chemical reaction between an acid & a base that yeilds a ____ & _____

Back 29

salt & water

Front 30

is this a strong or weak acid and why

HA + H20 ---> H20 + A-

Back 30

strong acid b/c complete dissociation

Front 31

partial dissociation means the acid is

Back 31

weak

Front 32

strong acids dissociate _____ into _____ in water

----->

Back 32

completely, ions

100% ionized
all starting reactants are converted into products

Front 33

weak acids dissociate very _____ into ions in water

<-----
------>

Back 33

slightly

Front 34

the Hydronium ion

Back 34

H30+

Front 35

what is H30+

Back 35

the Hydronium ion

Front 36

the ____ of a solution is normally specified by the concentration of _____ in moles per liter of solution, M

Back 36

the ACIDITY of a solution is normally specified by the concentration of H30+ (hydronium ion) in moles per Liter of solution, M

Front 37

strong acids: acid concentration =

Back 37

[H30+]

Front 38

weak acids: acid concentration >

Back 38

[H3O+}

Front 39

Pure water has a [H30+] =

Back 39

1 x 10 -7 M

Front 40

1 x 10 -7 M is what

Back 40

concentration of H30+ in pure water

Front 41

[ ] or brackets mean what

Back 41

molar concentration

Front 42

concentrations of species in acid-base chemistry are always expressed as

Back 42

molaRity

Front 43

sulfuric acid: H2SO4

Hydroiodic acid: HI

Hydrobromic acid: HBr

Hydrochloric acid: HCl

Nitric acid: HNO3
are all examples of _____acids

Back 43

strong acids

Front 44

Lithium hydroxide: LiOH
Sodium hydroxide: NaOH
Potassium hydroxide: KOH
Barium hydroxide: Ba(OH)2

are examples of strong ___

Back 44

bases

Front 45

water as an acid & base

H20 + H20 <-->H30+ + OH-

Ka=

Back 45

Ka = [H30+][OH-] / [H20][H20]

Front 46

the relative strength of a weak acid is quantified by the equilibrium constant,

Back 46

Ka

Front 47

Ka is the

Back 47

equilibrium constant that indicates the relative strength of a weak acid

Front 48

a large Ka means a ____ acid

Back 48

stronger

Front 49

of the following acids, which is the strongest based on Ka

H3PO4 (phosphoric acid) Ka= 7.1 x 10 -3 versus

NH4+ (ammonium ion) Ka=5.6 x 10 -10

Back 49

Phosphoric acid is stronger based on Ka (because 10 -3 is larger than 10 -10)

Front 50

Kw is the

Back 50

ion-product for water

Front 51

the ion-product of water is

Back 51

Kw

Front 52

PKw =

Back 52

PKw = -logKw

Front 53

what scale is used to express H+ ion concentration in water

Back 53

the pH scale

Front 54

pH of neutral soution =

Back 54

pH =7

Front 55

pH of acidic solution <

Back 55

7

Front 56

pH of basic solution >

Back 56

7

Front 57

express pH of an acidic solution <7 according to hydronium versus hydroxide ions

Back 57

[H30+] > [OH-]

Front 58

express pH of a neutral solution =7.00 in terms of hydronium & hydroxide ions

Back 58

pH =7

[H30+] = [OH-]

Front 59

express pH of a basic solution > 7 in terms of [H30+] & [OH-]

Back 59

pH > 7 is basic

[H30+] < [OH-]

Front 60

pH =

Back 60

- log[H30+]

pH = - log[H30+]

Front 61

- log[H30+] is

Back 61

pH = - log[H30+]

Front 62

pH is a________-scale. One pH unit of change means the hydrogen ion concentration changes _____ fold

Back 62

pH is a logarithmic scale, therefore one pH unit of change means the H+ concentration changes 10 fold

Front 63

these acids have more than one Hydrogen & can ionize more than once

Back 63

polyprotic acids

Front 64

biologically, the MOST important polyprotic acid is

Back 64

carbonic acid, H2CO3

Front 65

H2CO3 is

Back 65

carbonic acid= H2CO3

Front 66

H2CO3 <-->

&

HCO3 <--->

Back 66

H2CO3 <--> H+ + HCO3-

&

HCO3 <---> H+ + CO3 -2

Front 67

polyprotic acids can neutralize as many ____ ions as they have _____

Back 67

OH- ions as they have H+

Front 68

carbonic acid (H2CO3) & sulfuric acid (H2SO4) can neutralize ____ OH- ions

Back 68

2

Front 69

phosphoric acid (H3PO4) can neutralize ___ OH- ions

Back 69

3

Front 70

what is a buffer solution

Back 70

a buffer solution is one that maintains a constant pH in spite of addition of a lot of acid or base

Front 71

most buffers consist of a solution of a weak ___ and its ____

Back 71

acid & its salt

Front 72

what is the MOST IMPORTANT buffer in blood

Back 72

carbonic acid (H2CO3)

Front 73

the proton dissociation of an acid is characterized by an acid _______ & its ____

Back 73

the proton dissociation of an acid is characterized by an acid dissociation constant (Ka) & its pKa value

Front 74

pKa =

Back 74

pKa = - log10 (Ka)

Front 75

ionizable groups of ____ & _____ are critical for biological function

Back 75

Amino Acids & Proteins

Front 76

Protonated

express pH vs pKa

Back 76

Protonated

pH < pKa

Front 77

Deprotonated

express in terms of pH & pKa

Back 77

deprotonated

pH > pKa

Front 78

the _____ equation calculates the ionic form of the molecule at a given pH from the pKa value of each acid group

Back 78

Henderson-Hasselbach

Front 79

in general, a weak acid dissociate to a limited extent in water to what

HA --> <-- H+ + A-

Back 79

the hydronium ion & conjugate base

Front 80

the tendency of the acid (HA) to dissociate & donate a H+ is the

Back 80

Ka, the equilibrium constant for dissociation

Front 81

pKa =

Back 81

pKa = - logKa

Front 82

-logKa is the

Back 82

pKa

Front 83

the higher the Ka, the ____the tendency to dissociate ( ie the stronger the acid)

Back 83

greater

Front 84

the higher the Ka, the ____ the acid

Back 84

stronger

Front 85

H-H equation
the pH of solution of weak acid
*Dissociation constant = Ka = [H+]{A-]/ [HA]

isolate for H+

Back 85

[H+] = Ka *[HA]/[A-]

Front 86

lactic acid is a weak acid which means it __________dissociates in water

Back 86

only partially dissociates

Front 87

lactic acid dissociates in water resulting in ____ & ___

Back 87

lactate ion & H+

Front 88

pKa is the PH at which ___% of the acid is dissociated

Back 88

50%

Front 89

in the ___ form the substances are able to pass through the lipid membranes

Back 89

undissociated

Front 90

the dissociated (ionized) form of substrates (are/are not) able to pass through the lipid membrane

Back 90

are not

Front 91

the carbonic-acid-bicarbonate buffer in the blood

Back 91

CO2 + H20
carbonic anhydrase
H2CO3 (carbonic acid)
^
v
HCO3- + H+ (bicarbonate)

Front 92

carbonic-acid bicarbonate buffer

Back 92

pH = pK -log [ [CO2]/[HCO3-] ]

Front 93

if the pH < pKa then [HA]

Back 93

if the pH < pKa, then

[HA] >> [A-] + [H+]
weak acids barely dissociate

Front 94

if pH > pKa then [HA]

Back 94

if pH > pKa then

[HA] <<< [A-] + [H+]
weak acids will be majority dissociated

Front 95

the pH of the drug solution will depend upon the

Back 95

pKa

Front 96

buffers do this to pH

Back 96

stabalize

Front 97

phenobarbitol pKa

Back 97

pKa 7.4

Phenobarbitol

Front 98

given the H-H equation the

pH =

Back 98

pH = pKa + log [ionized] / [nonionized]

Front 99

all processes are at some ____; if you change the concentration/temperature/reactants/products, you will try to reach a new _____

Back 99

equilibrium; equilibrium

Front 100

pH of drug solution is dependent on the ___of a compound

Back 100

pKa