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Announcements “Limiting Reactants” lab write-up due tomorrow at start of discussion. Online HW 5 (Type I) due Monday 10/23 and (Type II) due Wednesday 10/25 by 7:00pm. Next Thursday (10/26): Stoichiometry Workshop (graded!) in lecture

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? 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 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 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 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 #3 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 #4 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

Clicker #5 Rate your personal confidence level with these concentration of ions questions. (There is no right answer.) I totally know what I’m doing. This makes sense to me but I’ll have to look over it a couple more times to be able to do it on my own. A couple of the parts of the problem are confusing. This makes absolutely no sense to me.

Clicker #6 What part is most confusing? Determining the limiting reactant. Figuring out which ions are in the container after the reaction. Calculating the moles of excess ions leftover. Calculating the concentrations of all the ions. Something else/more than one of these.