Announcements Be respectful – no electronics please! Exam 2 is on Thursday March 14 at 7 pm Thursday before start of spring break Post/Pre-lecture assignment due Thursday 8 am Textbook homework due Friday in discussion Limiting Reactants lab due Friday in discussion Lab again on Monday What is the purpose of the quicksand video?

So far… Stoichiometry: what a chemical reaction means, finding limiting and excess reactants ---------------------------- Today… Precipitation reactions Predicting products Solubility Molecular, complete, and net ionic equations

Iodine Clock Trial Volume A Volume B Volume H2O I 50 mL 80 mL 150 mL II 100 mL III 25 mL 175 mL

Clicker #1 You add 300.0 mL of water to 300.0 mL of a 2.00 M silver nitrate solution. How many of the following will change? I. total volume of the solution II. moles of solute in the solution III. mass of solute in the solution IV. concentration of the solution V. number of solute molecules in the solution A) 1 B) 2 C) 3 D) 4 E) 5

Clicker #2 Discussion Question What is the other product likely to be formed in this reaction? AgNO3 + Na2CO3  Ag2CO3 + ________ NaNO3 NO3Na Na2NO3 NO3Na2 Na3(NO3)2

Solubility Rules (Page 167) Most nitrate salts are soluble. Most salts of sodium, potassium, and ammonium cations are soluble. Most chloride 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.

Solubility Rules (Page 167) Most nitrate salts are soluble. Most salts of sodium, potassium, and ammonium cations are soluble. Most chloride 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. How many are soluble? PbCl2 NaCl BaSO4 Fe(OH)3 (NH4)2SO4

Precipitation Reactions Know how to use the solubility rules (you will be given them on the exam). Know how to write equations from reactants (ionic reactants). Understand what solutions “look” like at a very magnified level.

Solubility Rules (Page 167) Most nitrate salts are soluble. Most salts of sodium, potassium, and ammonium cations are soluble. Most chloride 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.

Clicker #3 Which combinations are expected to form precipitates? Neither #1 only #2 only Both #1 and #2 Most nitrate salts are soluble. Most salts of sodium, potassium, and ammonium cations are soluble. Most chloride 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.