chapt 9 ionic equilibria/ acid & base

Question 1

How do acidic buffers work?

Answer 1

When OH- is added, most of it is removed by reacting with a large reservoir of HA (acid)
OH- + HA»_space; H2O + A-
.
When H3O+ is added, most of it is removed by reacting with a large reservoir of A- (conjugate base).
H3O+ + A-»_space; H2O + HA

Question 2

What is present in an acidic / alkaline buffer? and what’s their pH?

Answer 2

Acidic: weak acid + conjugate base
pH < 7
.
Alkaline: weak base + conjugate acid + conjugate base
pH > 7

Question 3

How do alkaline buffers work?

Question 4

formula for pH of buffer soln for acidic and basic.
And which formula NOT to use

Answer 4

pH = pKa + lg([A- salt] / [HA initial])
.
derived from Ka = ([H3O+][A-] / [HA])
.
Don’t use [H30+] = sq root(Ka [acid]initial).
bcus there is a large reservoir of A-, this formula assumes [H3O+] = [A-]

Question 5

Max buffering capacity occurs when…

Answer 5

[HA] = [A-]
pH = pKa
OR
[B] = [BH+]
pOH = pKb

Question 6

How CO₃^2- HCO₃^- buffer system maintains the pH in the ocean

Answer 6

weak acid: HCO₃^-
conjugate base: CO₃^2-
.

Question 7

Ocean acidification due to increased CO2

Question 8

Process of Ocean acidification