1. Schedule Today (2/22): Continue Chapter 7
Should have read Sections (at least)
Monday (2/25): Finish Chapter 7
Start Chapter 8 on Wednesday
Wednesday (2/27): Start Chapter 8
Should have read Sections (at least)
Friday (2/29): Continue Chapter 8
Should have read through Section 8.7 (at least)

2. Clicker Question
You add 1.00 x 10–7 mol of HCl to 1.0 L of water at 25°C. What is the pH of the solution? a) 6.70 b) 6.79 c) 7.00 d) 7.21 e) 7.30

3. Problem Solving: A Journey
Where Are We Going?: What are we trying to solve? What does this mean?
Where Have We Been?: What do we know? What is given in the problem, and what is our knowledge base?
How Do We Get There?: How do we connect what we know to what we are trying to solve? Diagrams and more questions can be useful.

4. Problem Solving: Acids-Bases
What are the major species?
HF in water: HF and H2O
HCl in water: H3O+, Cl–, and H2O
What are the reactions in solution?
Always: H2O + H2O H3O+(aq) + OH–(aq)
Weak acid: HA(aq) + H2O H3O+(aq) + A–(aq)
Which reaction dominates?
Look at K values for the reactions

5. Clicker Question a) 3.18 b) 5.16 c) 6.37 d) 8.34 e) 10.32
Determine the pH of a 1.00M aqueous solution of H2CO3 at 25°C.
Ka1 = 4.3 x 10-7
Ka2 = 4.8 x 10-11
a) 3.18
b) 5.16
c) 6.37
d) 8.34
e) 10.32

6. Polyprotic Acids
Ka1 = 4.3 x 10-7 pKa1 = Ka2 = 4.8 x pKa2 = 10.32

7. Polyprotic Acids
Ka1 = 4.3 x 10-7; pKa1 = 6.37 Ka2 = 4.8 x 10-11; pKa2 = Ka1 = 7.5 x 10-3; pKa1 = 2.12 Ka2 = 6.2 x 10-8; pKa2 = 7.21 Ka3 = 4.8 x 10-13; pKa3 = 12.32

8. Polyprotic Acids
For a solution of a polyprotic acid (X M of H2A or H3A) we generally only concern ourselves with the first dissociation. Why? See Examples 7.10 and 7.11 in your text for H2SO4, and how concentration plays a role in this.

9. Clicker Question a) 2.90 b) 5.10 c) 7.00 d) 8.90 e) 11.10
Determine the pH of a 0.10M aqueous solution of KCN at 25°C.
(for HCN Ka = 6.2 x 10–10)
a) 2.90
b) 5.10
c) 7.00
d) 8.90
e) 11.10