Monoprotic and Polyprotic Equilibria

Question 1

define conjugate acid-base pair

Answer 1

acid and a base that differ only through the loss or gain of a single proton

conjugate of a WA is a WB

Question 2

define formal concentration

Answer 2

total number of moles of a compound dissolved in a L

Question 3

define zwitterion

Answer 3

molecule that contains an equal number of + and - charged functional groups

Question 4

define dissociation constants

Answer 4

Ka = [H+][A-]/[HA] or x^2/F-x
strong acid = high Ka and low pKa

Kb = [BH+][OH-]/[B] or x^2/F-x
strong base = high Kb and low pKb

Question 5

define the fraction of dissociation/assocation

Answer 5

a = x/x+(F-x)

we can neglect x in the denominator if it works out to be less than 1% of F (most of the time)

Question 6

define buffer

Answer 6

• a buffered solution resists changes in pH when acids and bases are added, or when dilution occurs
• a mixture of acid with CB

Question 7

what is the henderson-hasselbalch equation

Answer 7

acid: pH = pKa + log ([a-]/[ha]

base: same but [b]/[bh+]

Question 8

can you make a diprotic buffer?

Answer 8

Yes! you just write out 2 henderson-hasselbalch equations, both of which are true. depending on what step we know and the concentration, that will determine what equation we use

Question 9

how do Ka/Ka values change with polyprotic acids/bases?

Answer 9

your K value with have a subscript for every addition protons that is taken away or added.

1 proton gone = Ka1
2 protons added = Kb2

Question 10

define isoince point/pH

Answer 10

the pH produced by the pure, neutral, polyprotic acid

Question 11

define isoelectric point/pH

Answer 11

the pH at which the average charge of the polyprotic acid is 0

Question 12

define proteome

Answer 12

entire composition of proteins that can be, or is, expressed by a cell, tissue or organism