Creating a Positive Learning Environment for Everyone Be respectful of your classmates Save conversation for clicker portions of lecture Put cell phones in “airplane” mode Turn off tablets Close laptops

Announcements Lon Capa HW #4 has been opened. Lab this week (with lab write-up) Prelecture assignments and textbook homework due as usual

Clicker #1 Balance the following equation and determine the sum of the coefficients: C2H5OH + O2 → CO2 + H2O A) 4 B) 5 C) 8 D) 9 E) 10 This is a quick way for us to see if you balanced the equation correctly.

Clicker #2 Combustion of Ethane C2H6 + O2 → CO2 + H2O Which is not an acceptable way to balance this equation? (Does not have to be in standard form.) A) C2H6 + 3.5O2 → 2CO2 + 3H2O B) 4C2H6 + 14O2 → 8CO2 + 12H2O C) 2C2H6 + 7O2 → 4CO2 + 6H2O D) C2H6 + 7O2 → 2CO2 + 3H2O E) All four are acceptable.

Clicker #3 What are the possible products? AgNO3(aq) + KCl(aq) → ? A) AgCl and KNO3 B) AgNO3 and KCl C) AgK and NO3Cl D) Any of the above could be the products.

Clicker #4 So what is true about KNO3? A) KNO3 is aqueous (soluble) in all three reactions. B) KNO3 is the solid in reactions 1 and 2 but not reaction 3. C) KNO3 is the solid in reaction 1 but not in reactions 2 and 3. D) KNO3 is the solid in reaction 2 but not in reactions 1 and 3 E) KNO3 is the solid in reaction 3 but not in reactions 1 and 2.

Solubility Rules (Page 127) 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 127) 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. 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.

Equations Molecular Complete Ionic Net ionic Example: Aqueous barium nitrate + aqueous potassium sulfate 

Equations Molecular Complete Ionic Net ionic Example: Aqueous iron(III) nitrate + aqueous sodium hydroxide 