1. Announcements Exams will be handed back in lab next week.
Quick “open-book” quiz at end of class today.

2. Lab Information
Metal hydroxide solubility
pH titration (on Friday)

3. An equilibrium will shift in response to change in the system or its environment
LeChatelier’s Principle
If a chemical system at equilibrium experiences a change in concentration, temperature, volume, or partial pressure, then the equilibrium shifts to counteract the imposed change and a new equilibrium is established.

4. The effect of concentration changes on equilibria
Add product [C]
Remove reactant [A]
Remove all of reactant [B] and product [D]

5. The effect of volume changes on equilibria
Equilibrium will shift to side with fewer moles of gas

6. The effect of temperature changes on equilibria
Endothermic reactions
Exothermic reactions

7. LeChatelier’s Principle- Quantitative
1-Liter flask contains 0.50 mol butane and 1.25 mol isobutane (at equilibrium). We then add 0.50 mol and butane. What happens and what are the final concentrations of isobutane and butane?

8. Chapter 16
Acid-base equilibria

9. Acids and Bases- Overview
pH and pOH
Relationship of conjugate pair acid-base strength.
When acids or bases control pH:
determine K
predict pH
When pH controls acid/base state:
predict acid/base state
use acid/base state to determine pH
Buffer action
pH titration curves

10. pH and pOH

11. Water autoionization

12. pH and pOH calculations
[H3O+][OH-] = 1.0 x 10-14
pH = -log[H3O+] pOH = -log[OH-]
[H3O+] = 10-pH [OH-] = 10-pH
pH + pOH = 14.00
What is the pH of [H3O+] = 4.6 x 10-5?
What is the pOH of [OH-] = 3.3 x 10-4?
What is the pOH of [H3O+] = 4.6 x 10-5?
What is the [H3O+] when the pH = 4.2?

13. What is the pH when [H3O+] = 0.045 M?
13.995
-1.35
1.35

14. What is the pH when [OH-] = 6.5 x 10-4 M?
3.18
-3.18
10.81
15.18

15. What is the [H3O+] when pH = 3.66 M?
2.18 x 10-4
10.34
4570
3.66

16. What is the [OH-] when pH = 5.84 M?
1.45 x 108
3.31 x 10-6
6.92 x 10-9
5.84

17. Strong acids and bases ionize completely
Strong monoprotic acids
[H3O+] = [acid]
Strong diprotic acid
[H3O+] = 2[acid]
Strong monoprotic base
[OH-] = [base]
Strong diprotic base
[OH-] = 2[base]

18. Quiz time!