Buffers Flashcards
1
Q
Define buffers + requirements
A
A buffer is a solution that will not change pH after a strong acid or base has been added. They need to have a weak acid or base and its conjugate.
2
Q
Ways to make a buffer
A
- Put weak A/B and its conjugate into soln
- Add H+ to weak base and form conj acid
- Add OH- to weak acid and form conj base
3
Q
Formula to find pH of a base
A
pH = pKa + log( [A-] / [HA] )
4
Q
Equivalence point + properties
A
moles of original acid = moles of added strong base
with strong acid, pH = 7
with weak acid, ph >7
5
Q
Before half equivalence
pH ( ) PKa
[A-] ( ) [HA]
A
<
6
Q
Half equivalence point + properties
A
moles of added base = ½ moles of added acid (pH=pKa)
(weak acid / strong base)
7
Q
After half equivalence
pH ( ) PKa
[A-] ( ) [HA]
A
>
8
Q
Henderson Hasselback Formula
A
pH = pKa + log ([A-]/[HA])
9
Q
Weak acid titrated by strong base, find pH with
A
limiting reactant and weak acid problem
