1. ANNOUNCEMENTS Acid-Base Homework has been posted on OWL Exams and Quizzes handed back in lab this week. Answer keys will be posted on Wednesday

2. What is the real range of pH’s that are possible? Can pH be zero? Can pH be negative? Can pH be greater than 14?

3. Changing the pH of a solution is harder the farther away you are from neutral pH How much acid does it take to go from pH=1 to pH=2? How much acid does it take to go from pH=5 to pH=6? HCl molar mass=36.46 g/mol

4. Conjugate Acid-Base Pairs Different definitions of acids and bases Brønsted-Lowry ◦ Acid = H + (proton) donor ◦ Base = H + (proton) acceptor ◦ Acid-base reaction involves proton transfer ◦ Conjugate acid/base = what is left on the other side after the proton has been transferred AcidConjugate base HFF-F- NH 4 + NH 3

5. What is the conjugate base of CH 3 CO 2 H? 1. CH 3 CO 2 H 2 2. CH 3 CO 2 - 3. CH 3 CO 3

6. What is the conjugate acid of HPO 4 2-? What is the conjugate acid of HPO 4 2- ? 1. H 2 PO 4 - 2. H 3 PO 4 3. PO 4 3-

7. Acid (or base) strength depends on the equilibrium constant

8. Lab Information-pH titration

10. Types of pH Calculations 1. Acid strength (K a ) from pH Acid strength (K a ) from pH 2. K b from pH K b from pH 3. [acid] from pH for weak acid [acid] from pH for weak acid 4. [base] from pH for weak base [base] from pH for weak base 5. pH of solution from [acid] pH of solution from [acid] 6. Predict pH of a strong/weak acid Predict pH of a strong/weak acid 7. Predict pH of strong/weak base Predict pH of strong/weak base

11. pH Measurements are used to determine acid strength (K a ) A 0.10M solution of oxalic acid has a pH of 1.48. What is the K a value for oxalic acid?

12. What is the value of K a for an acid, HA, for which a 0.240 M solution has a pH of 3.28? Is this acid stronger or weaker than oxalic acid? (K a =0.016)

13. Determining K b from pH data A 0.300 M solution of a weak base has a pH of 9.20. What is K b ?

14. Determine the[acetic acid] in vinegar from pH measurements

15. Determine the [NH 3 ] in household ammonia from pH measurements

16. Determine the pH of a weak acid solution from [acid] What is the pH of a 0.15M solution of HF?

17. Determine the pH of a weak base solution from [base] What is the pH of a 0.15M solution of Ca(OH) 2 ?