SI Chem 178 Ch 16, 17 Leader: Emily February 26, 2013

Review of Ch 16 16.75 Ephedrine (nasal sprays) is a weak organic base: (why!?) C10H15ON(aq) + H2O(l)  C10H15OH+(aq) + OH-(aq) A 0.035M solution has a pH of 11.33. What are the equilibrium concentrations of each of the species in solution? What is it’s Kb? What is it’s pOH?

16.86 An unknown salt is either: KBr, NH4Cl, KCN, or K2CO3. A 0.1M solution of this mysterious salt is neutral. Which salt is dissolved?

Review Acid Strength Patterns… ______New Stuff (Ch 17)

Use arrows (up/down) to compare the following concepts:

______Ionization of weak electrolyte ______Concentration of strong electrolyte with common ion

17.14 Given B(aq) + H2O(l)  HB+(aq) + OH-(aq) and using Le Chatelier’s principle, explain what the presence of a salt of HB+ does to the ionization of B. What is a salt that can decrease the ionization of NH3 in solution? What is the pH of a 1L solution containing 0.3 moles of acetic acid and 0.3 moles of sodium acetate? How do we approach this…. 1. What is the common ion?

2. Which species is a strong electrolyte, and which is weak? What will be floating around in solution?

3. Which species will actually affect pH?

4. Make your ICE table here… What must you be careful of in your “I” column? Can we likely make our 5% assumption here? What are our molarities?

5. What is your Ka equation? Write it conceptually and numerically. (The Ka of acetic acid is 1.8*10^-5)

6. What is your pH?

7. Compare: What would the pH of a simple 0.3M acetic acid solution be? (Without the sodium acetate? (And therefore, what does this tell us? Whose principles apply here?)

17.18 a) What is the % ionization of 0.125M lactic acid? (Ka= 1.5*10^-5) b) What is the % ionization of 0.125M lactic acid with 0.0075M Sodium lactate added?