1. U2 S2 L4 Ka and Kb calculations p 587-591: pH and Ka of a Weak Acid p 592-594: The Base Dissociation Constant, Kb Homework: p 591: # 5, 6, 7, 8, 9 and 10 p 595: # 11, 12, 13, 14, 15 and 16 p 597: # 1, 2, 3, 4, 5 and 6 p 617: # 7, 8, 10 and 11

2. Upon completion of this lesson, you should be able to: calculate the value of one of K a (or K b ) or an equilibrium concentration given all other values for a system. calculate pH (or pOH) given the initial concentration of a weak acid (or weak base) and K a (or K b ). use the quadratic equation to complete K a or K b calculations

3. Using percent ionization Percent ionization data can only be used for acid concentrations of 0.10 mol/L (see note on bottom of table) Calculate the pH of a 0.10 M solution of methanoic acid.

4. Finding % ionization: A 0.15 M boric acid solution has a pH of 5.00, calculate the percent ionization of boric acid.

5. Calculating K A cleaning solution is prepared by dissolving ammonia in water. The equilibrium concentrations of ammonia and hydroxide found to be 0.35 mol/L and 0.0025 mol/L respectively. Calculate K b

6. Calculation hydronium or hydroxide using K Propanoic acid solution has K a = 1.3 x 10 -5 and an equilibrium concentration of 0.050 mol/L. Calculate the concentration of hydronium ions and pH at equilibrium.

7. ICE tables (brrrrrr…!) A nitrous acid solution has an initial concentration of 0.25 mol/L. At equilibrium the hydronium concentration is 0.013 mol/L. Calculate K a.

8. Calculation Ka from pH An aqueous methanoic acid solution has an initial molar concentration of 0.75 M. The pH of the solution at equilibrium is 1.95. Calculate the K a of a methanoic acid.

9. An aqueous 0.50 mol/L sodium sulfite solution is prepared. The pH at equilibrium is 10.45. Calculate the K b for the sulfite ion.

10. Quadratic equation. A 0.022 mol/L aspirin (acetylsalicylic acid) solution is made by dissolving a 500.0 mg tablet in about 125 mL of water. A condensed formula for aspirin is C 8 H 7 O 2 COOH. Given K a for aspirin is 3.3 x 10 -4, calculate the pH of the aspirin solution

11. Calculate the pH of a 0.50 mol/L ethanoic acid solution