21.1 - 21.6 Acids, bases and buffers Flashcards
Give the Bronsted-Lowry definition of an acid
A proton/H+ donor
Give the Bronsted-Lowry definition of a base
A proton/H+ acceptor
Give the Bronsted-Lowry definition of an acid-base reaction
A reaction involving proton transfer
Define amphoteric
A substance that acts as an acid or a base i.e water
Give the Lewis definition of an acid
An electron pair acceptor
Give the Lewis definition of a base
An electron pair donor
Define a strong acid
An acid that fully dissociates in water
What is the equation for calculating pH?
-log [H+]
What is the equation for calculating [H+]?
[H+] = 10^-pH
How do you calculate the dilution of a strong acid?
C1 x V1 = C2 x V2
Define Kw
Kw = [H+] x [OH-]
Why is pure water always neutral?
Because [H+] = [OH-]
How do you calculate the pH of strong alkalis?
- Calculate [OH-]
- Use Kw to calculate [H+]
- Use pH = -log[H+]
How do you use Kw to calculate [H+]?
[H+] = Kw/[OH-]
How do you calculate the pH of a mixture of a strong acid and a strong base?
- moles H+
- moles OH-
- XS moles of H+ or OH-
- [H+] or [OH-]
- pH
How do you calculate the pH of a weak acid?
[H+]^2 = Ka x [Ha]
How do you calculate the pH of a mixture of a weak acid and a strong base?
- Calculate moles HA
- Calculate moles OH-
- Calculate moles XS HA or OH-
XS HA:
- Moles HA left
- Moles A- formed
- [HA] and [A-]
- [H+] = Ka x [HA] / [A-]
- pH
XS OH-:
- [OH-]
- [H+] = Kw/[OH-]
- pH
List the strong acids
HCl
HNO3
H2SO4
List the weak acids
Carboxylic acids
List the strong bases
NaOH
KOH
Ba(OH)2
List the weak bases
NH3
Give the Ka equation
Ka = [H+][A-] / [HA]
If a weak acid in solution with nothing else:
Ka = [H+]^2 / [HA]
Describe how to convert between Ka and pKa
pKa = -log(Ka)
Ka = 10^-pKa
Describe the relation between Ka and pKa and pH
Ka up = pH down
pKa down = pH down
