Chapt. 7: Acids & Bases

1. Strategy for Solving Acid-Base Problems

1.1. List major species

1.2. Look for rxns that go to completion, determine [products]

1.3. Define each major species as an acid or base

1.4. Pick equilibrium that controls pH

2. Polyprotic Acids

2.1. More than one H+ dissociating in steps

2.2. Examples

2.2.1. Carbonic Acid

2.2.2. Phosphoric Acid

2.2.3. Sulfuric acid

3. Strong Acid Solutions in Which Water Contributes to the H+ Concentration

3.1. Applies when [HA]~10^-7 M

3.2. Charge balance equation

3.3. Same procedure works for strong base solutions

4. Acid Solutions in Which Water Contributes to the H+ Concentration

4.1. Dilute solution of a very weak acid

4.2. Determine [H+], [OH-], [HA] and [A-]

4.3. Re-derive Ka in terms of [H+] & [HA]0

5. Acid-Base Properties of Salts

5.1. Salt: an ionic compound that breaks into its ionic components when dissolved in water

5.2. Salt solutions

5.2.1. Neutral

5.2.2. Basic

5.2.3. Acidic

5.2.4. Both acidic & basic

5.3. Base strength in aqueous solution

6. PP acids dissociate in successive steps, each with a weaker Ka than the previous step

7. To determine the pH of a salt solution, answer the question: What are the acid-base properties & strength of each component?

8. For an aqueous solution of an acid/base pair, you can calculate Kb from Ka & Kw or vice versa

9. To solve problems where H2O contributes H+, use Ka, Kw, material and charge balance

10. The Nature of Acids & Bases

10.1. Definitions

10.1.1. Arrhenius

10.1.2. Brønstead & Lowry

10.1.3. Lewis

10.2. Dissolution of an acid in water

10.3. Ka

11. Bases

11.1. Strong bases dissociate completely in water

11.2. Hydroxides of the Group 1A & 2A elements all strong bases

11.3. Some bases accept protons but do not contain hydroxide

11.4. Kb

12. Acid Strength

12.1. Strong & weak Acids

12.2. Diprotic acids

12.3. Halo-acids

12.4. Water as an acid & base

13. The pH Scale

13.1. pH definition

13.2. Other log scales

14. Calculating the pH of Strong Acid Solutions

14.1. Identify major species

14.2. Focus on chemistry of solution components

14.3. Consider sources of H+ from all major species

15. Calculating the pH of Weak Acid Solutions

15.1. A weak acid dissolved in water is a model for any equilibrium in solution

15.2. pH of a mixture of two weak acids of very different strengths

15.3. Percent dissociation

16. Definitions of acid & base predict chemistry

17. Conjugate base: everything in the acid except the H+ Conjugate acid: everything in the base plus a H+

18. Stronger the acid, weaker the conjugate base Stronger the base, weaker the conjugate acid

19. Autoionization of water gives very important Kw=10^-14

20. Solve A/B problems strategically

20.1. Key Strategy: IDENTIFY MAJOR SPECIES

20.2. Remember autoionization of H2O, determine if it is important

21. Strong bases dissociate to produce [OH-] ≈ [Base] Weak bases react with water