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?

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)

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.

Example #1 What volume of a 0.100 M KI solution is needed to completely react with 100.0 mL of a 0.100 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?

Example #1 What volume of a 0.100 M KI solution is needed to completely react with 100.0 mL of a 0.100 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?

Example #1 What volume of a 0.100 M KI solution is needed to completely react with 100.0 mL of a 0.100 M Pb(NO3)2 solution? 200. mL KI How many of each type of ions are present before the reaction? 0.0100 mol Pb+2, 0.0200 mol NO3- 0.0100 mol K+, 0.0100 mol I- What is the mass of solid produced? What are the concentrations of the ions left in solution after the reaction is complete?

Example #1 What volume of a 0.100 M KI solution is needed to completely react with 100.0 mL of a 0.100 M Pb(NO3)2 solution? 200. mL KI How many of each type of ions are present before the reaction? 0.0100 mol Pb+2, 0.0200 mol NO3- 0.0100 mol K+, 0.0100 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?

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.

Clicker #3 How many moles of nitrate ions are present in the solution after the reaction is complete? A) 0 moles NO3- B) 0.0100 moles NO3- C) 0.0200 moles NO3- D) 100.0 moles NO3- E) I have no idea.

Example #1 What volume of a 0.100 M KI solution is needed to completely react with 100.0 mL of a 0.100 M Pb(NO3)2 solution? 200. mL KI How many of each type of ions are present before the reaction? 0.0100 mol Pb+2, 0.0200 mol NO3- 0.0100 mol K+, 0.0100 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?

Example #1 What volume of a 0.100 M KI solution is needed to completely react with 100.0 mL of a 0.100 M Pb(NO3)2 solution? 200. mL KI How many of each type of ions are present before the reaction? 0.0100 mol Pb+2, 0.0200 mol NO3-, 0.0100 mol K+, 0.0100 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–] = 0.0667 M [K+] = 0.0667 M

“Maximum State of Confusion?”

“Maximum State of Confusion?”

“Maximum State of Confusion?”

“Maximum State of Confusion?”

“Maximum State of Confusion?”

Example #2 Same reaction (and volumes) but different starting amounts in moles: Pb(NO3)2(aq) + 2KI(aq) → PbI2(s) + 2KNO3(aq) 0.0100 mol 0.0500 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

Example #2 Same reaction (and volumes) but different starting amounts in moles: Pb(NO3)2(aq) + 2KI(aq) → PbI2(s) + 2KNO3(aq) 0.0100 mol 0.0500 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

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.

Example #2 Same reaction (and volumes) but different starting amounts in moles: Pb(NO3)2(aq) + 2KI(aq) → PbI2(s) + 2KNO3(aq) 0.0100 mol 0.0500 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

Clicker #5 What volume should be used to calculate the final concentration of the potassium ions remaining in the solution? A) 0.0150 mL B) 100. mL C) 200. mL D) 300. mL

Example #2 Same reaction (and volumes) but different starting amounts in moles: Pb(NO3)2(aq) + 2KI(aq) → PbI2(s) + 2KNO3(aq) 0.0100 mol 0.0500 mol What are the concentrations of the ions left in solution after the reaction is complete? [Pb2+] = 0 M [I–] = 0.100 M [NO3–] = 0.0667 M [K+] = 0.167 M 100. mL 200. mL