1. Announcements Precipitation lab write-up due tomorrow at the start of discussion Text HW due tomorrow in discussion Lon-capa HW #4 Type 1 due Monday, Oct 14 th at 7:00pm Lon-capa HW #4 Type 2 due Wednesday, Oct 16 th at 7:00pm

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

3. Solubility Rules (Page 172) 1. Most nitrate salts are soluble. 2. Most salts of sodium, potassium, and ammonium cations are soluble. 3. Most chloride salts are soluble. Exceptions: Ag + and Pb 2+. 4. Most sulfate salts are soluble. Exceptions: Ca 2+, Ba 2+, and Pb 2+. 5. Most hydroxide salts are only slightly soluble. Soluble ones are: Na +, K +, and Ca 2+. 6. Most sulfide, carbonate, and phosphate salts are only slightly soluble.

4. Clicker #1 When aqueous silver nitrate and aqueous sodium chromate are mixed, what are the formulas of the products? A)Na 2 NO 3 and AgCrO 4 B)NaNO 3 and Ag 2 CrO 4 C)NaNO 3 and AgCrO 4 D)Na 2 NO 3 and AgCr 2 O 7 E)NaNO 3 and Ag 2 Cr 2 O 7

5. Clicker #2 When potassium chloride and sodium nitrate are mixed, what precipitate will form? KCl (aq) + NaNO 3(aq) → A)KNO 3 B)NaCl C)KCl D)NaNO 3 E)No precipitate will form. Solubility Rules Most nitrate salts are soluble. Most salts of sodium, potassium, and ammonium cations are soluble.  Most chloride salts are soluble. Exceptions: Ag + and Pb 2+.  Most sulfate salts are soluble. Exceptions: Ca 2+, Ba 2+, and Pb 2+.  Most hydroxide salts are only slightly soluble. Soluble ones are: Na +, K +, and Ca 2+.  Most sulfide, carbonate, and phosphate salts are only slightly soluble.

6. Clicker #3 Will the resulting solution conduct electricity? A)No. There is no precipitate formed and a solid is required to conduct electricity. B)No. The resulting solution is pure water which does not conduct electricity. C)Yes. The resulting solution is pure water which conducts electricity. D)Yes. The resulting solution contains ions which conduct electricity.

7. Solubility Rules (Page 172) 1. Most nitrate salts are soluble. 2. Most salts of sodium, potassium, and ammonium cations are soluble. 3. Most chloride salts are soluble. Exceptions: Ag + and Pb 2+. 4. Most sulfate salts are soluble. Exceptions: Ca 2+, Ba 2+, and Pb 2+. 5. Most hydroxide salts are only slightly soluble. Soluble ones are: Na +, K +, and Ca 2+. 6. Most sulfide, carbonate, and phosphate salts are only slightly soluble.

8. 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.

9. Clicker #4 Is the resulting net ionic equation a chemical reaction? H + (aq) + OH – (aq) → H 2 O (l) A)Yes. There is a new compound formed from H + and OH –. B)Yes. Whenever two compounds are mixed, a chemical reaction always occurs. C)No. A precipitate (solid) must be formed to be considered a chemical reaction. D)No. There was no color change so a chemical reaction did not occur.