1. Example Answers (on handout) Soluble or Insoluble? 7. K 3 PO 4  Soluble 8. Fe 3 (PO 4 ) 2  Insoluble 9. PbCl 2  Insoluble (exception) 10. FeSO 4  Soluble 11. (NH 4 ) 2 S  Soluble (exception) 12. PbS  Insoluble

2. LAB THIS WEEK- ANALYSIS OF SILVER GROUP IONS OWL HOMEWORK- NEW ASSIGNMENTS POSTED ACID-BASE, SOLUBILITY, NET IONIC EQUATIONS Announcements

4. Which of the following is soluble? 1. AlPO 4 2. PbBr 2 3. Al(OH) 3 4. FeSO 4

5. Which of the following is insoluble? 1. Al(NO 3 ) 3 2. PbC 2 O 4 3. NaOH 4. FeF 3

6. pH Review What is the pH of a 0.25M solution of NaOH?  pH + pOH = 14pOH=-log[OH - ]  NaOH is a strong base  [NaOH]=[OH - ] pOH= -log[0.25]=0.602 pH= 14 - pOH = 14 = 0.602 = 13.4 What is the [H 3 O + ] of this solution?  [H 3 O + ] = 10 -pH = log -1 (-pH) [H 3 O + ] = 10 (-13.4) = 3.98 x 10 -14 M

7. Conjugate Acid-Base Pairs Anions of weak acids are weak bases  Conjugate acids and conjugate bases  Example: CH 3 COOH = weak acid CH 3 COO - = weak base What would this look like in a reaction? CH 3 COONa + HCl  ? Anions of strong acids are neutral Weak AcidWeak Base CH 3 COOHCH 3 COO - NH 4 + NH 3 H 2 CO 3 CO 3 2- H2C2O4H2C2O4 C 2 O 4 2- H 2 SO 3 SO 3 2- H2SH2SS 2- H 3 PO 4 PO 4 3- HCNCN - HFF-F- NHO 2 NO 2 - HClOClO -

8. Conjugate Acids and Bases- More Examples HCl + NaCN  ? HNO 3 + AlPO 4  ?

9. Net Ionic Equations 1. Write all reactants as they exist in solution 2. Identify acids and bases  Need both acid and base present  Look for “hidden bases” (anions of weak acids) 3. Ions that form insoluble compounds will form precipitates 4. Look for known gas-forming reactions 5. Write out the products as they exist in solution 6. Cancel spectator ions

10. Precipitation Reactions Net Ionic Equations Pb(NO 3 ) 2 + K 2 CrO 4  ? Pb(NO 3 ) 2 + KI  ? Ba(NO 3 ) 2 + Na 2 C 2 O 4  ?

11. Gas Forming Reactions Special class of acid-base reactions Combination of double displacement (swap) and decomposition reactions  2HCl + Na 2 CO 3  ? Gas Forming Reactions 2H + + CO 3 2-  H 2 O(l) + CO 2 (g) 2H + + S 2-  H 2 S(g) 2H + + SO 3 2-  H 2 O(l) + SO 2 (g) 2H + + M  M 2+ + H 2 (g)