1. Announcements Be respectful – no electronics please!
Exam 2 is on Thursday March 14th at 7:00 pm (Conflict at 5:00 pm that day)
Please let me know about conflicts to the conflict!
Stoichiometry Workshop Tuesday in Lecture
Pre-lecture assignments due Tuesdays & Thursday at 8:00 am
HW 4 Due Wednesday at 10:00 pm
Lab due Friday in discussion
Textbook homework due Friday in discussion
What is the purpose of the quicksand video?

2. Exam Info 40% Basic Knowledge & Skills 40-50% Application Questions
(Pre/Post-lecture questions, book problems)
40-50% Application Questions
(Lon-Capa homework questions, lab questions, lecture demonstrations)
10-20% New Problems
(Same material, but connected in different ways, or extensions of other problems)

4. Clicker #1
When lead(II) nitrate and potassium iodide are mixed, what precipitate will form?
Pb(NO3)2(aq) + KI(aq) →
A) KNO3
B) KI
C) Pb(NO3)2
D) PbI2
E) No precipitate will form.
Solubility Rules
Most nitrate salts are soluble.
Most salts of sodium, potassium, and ammonium cations are soluble.
Most chloride and iodide salts are soluble. Exceptions: Ag+ and Pb2+.
Most sulfate salts are soluble. Exceptions: Ca2+, Ba2+, and Pb2+.
Most hydroxide salts are only slightly soluble. Soluble ones are: Na+, K+, and Ca2+.
Most sulfide, carbonate, and phosphate salts are only slightly soluble.

5. Example #1
What volume of a M KI solution is needed to completely react with mL of a M Pb(NO3)2 solution?
How many of each type of ions are present before the reaction?
What is the mass of solid produced?
What are the concentrations of the ions left in solution after the reaction is complete?

6. Example #1
What volume of a M KI solution is needed to completely react with mL of a M Pb(NO3)2 solution? 200. mL KI
How many of each type of ions are present before the reaction?
What is the mass of solid produced?
What are the concentrations of the ions left in solution after the reaction is complete?

7. Example #1
What volume of a M KI solution is needed to completely react with mL of a M Pb(NO3)2 solution? 200. mL KI
How many of each type of ions are present before the reaction?
mol Pb+2, mol NO3-
mol K+, mol I-
What is the mass of solid produced?
What are the concentrations of the ions left in solution after the reaction is complete?

8. Example #1
What volume of a M KI solution is needed to completely react with mL of a M Pb(NO3)2 solution? 200. mL KI
How many of each type of ions are present before the reaction?
mol Pb+2, mol NO3-
mol K+, mol I-
What is the mass of solid produced?
4.61 g PbI2
What are the concentrations of the ions left in solution after the reaction is complete?

9. Clicker #2
What ions are left in solution after the reaction is complete?
I. Pb2+
II. NO3–
III. K+
IV. I–
A) II and III
B) I and IV
C) II, III and IV
D) I, II, III and IV
E) No ions are left in solution after the reaction is complete.

10. Clicker #3
How many moles of nitrate ions are present in the solution after the reaction is complete?
A) 0 moles NO3-
B) moles NO3-
C) moles NO3-
D) moles NO3-
E) I have no idea.

11. Example #1
What volume of a M KI solution is needed to completely react with mL of a M Pb(NO3)2 solution? 200. mL KI
How many of each type of ions are present before the reaction?
mol Pb+2, mol NO3-
mol K+, mol I-
What is the mass of solid produced? 4.61 g PbI2
What are the concentrations of the ions left in solution after the reaction is complete?

12. Example #1
What volume of a M KI solution is needed to completely react with mL of a M Pb(NO3)2 solution? 200. mL KI
How many of each type of ions are present before the reaction? mol Pb+2, mol NO3-, mol K+, mol I-
What is the mass of solid produced? 4.61 g PbI2
What are the concentrations of the ions left in solution after the reaction is complete?
[Pb2+] = 0 M
[I–] = 0 M
[NO3–] = M
[K+] = M

13. “Maximum State of Confusion?”

14. “Maximum State of Confusion?”

15. “Maximum State of Confusion?”

16. “Maximum State of Confusion?”

17. “Maximum State of Confusion?”

18. Example #2
Same reaction (and volumes) but different starting amounts in moles:
Pb(NO3)2(aq) + 2KI(aq) → PbI2(s) + 2KNO3(aq)
mol mol
What is the mass of solid produced?
What are the concentrations of the
ions left in solution after the reaction is
complete?
100. mL
200. mL

19. Example #2
Same reaction (and volumes) but different starting amounts in moles:
Pb(NO3)2(aq) + 2KI(aq) → PbI2(s) + 2KNO3(aq)
mol mol
What is the mass of solid produced?
What are the concentrations of the
ions left in solution after the reaction is
complete?
100. mL
200. mL
4.61 g PbI2

20. Clicker #4
What ions are left in solution after the reaction is complete?
I. Pb2+
II. NO3–
III. K+
IV. I–
A) II and III
B) I and IV
C) II, III and IV
D) I, II, III and IV
E) No ions are left in solution after the reaction is complete.

21. Example #2
Same reaction (and volumes) but different starting amounts in moles:
Pb(NO3)2(aq) + 2KI(aq) → PbI2(s) + 2KNO3(aq)
mol mol
What is the mass of solid produced?
What are the concentrations of the
ions left in solution after the reaction is
complete?
100. mL
200. mL
4.61 g PbI2

22. Clicker #5
What volume should be used to calculate the final concentration of the potassium ions remaining in the solution?
A) mL
B) 100. mL
C) 200. mL
D) 300. mL

23. Example #2
Same reaction (and volumes) but different starting amounts in moles:
Pb(NO3)2(aq) + 2KI(aq) → PbI2(s) + 2KNO3(aq)
mol mol
What are the concentrations of the
ions left in solution after the reaction is
complete?
[Pb2+] = 0 M
[I–] = M
[NO3–] = M
[K+] = M
100. mL
200. mL