1. Dr. S. M. Condren Chapter 15 Acids and Bases

2. Dr. S. M. Condren Arrhenius Acid-Base Theory Arrhenius, Svante August (1859-1927), Swedish chemist 1903 Nobel Prize in chemistry acid - proton donor base - hydroxide ion donor

3. Dr. S. M. Condren Bronsted-Lowry Acid-Base Theory acid - proton donor base - proton acceptor strong vs. weak acids and bases strong - completely ionized weak - partially ionized

4. Dr. S. M. Condren Acid-Base Reactions hydronium ion hydrated proton, H 3 O + used interchangeably for H + indicators natural or synthetic substance that changes color in response to the nature of its chemical environment.

5. Dr. S. M. Condren Indicators Indicators are used to provide information about the degree of acidity of a substance (pH) or the state of some chemical reaction within a solution being tested or analyzed.

6. Dr. S. M. Condren Indicators One of the oldest indicators is litmus, a vegetable dye that turns red in acid solutions and blue in basic ones. Other indicators include alizarin, methyl red, and phenolphthalein, each one being useful for a particular range of acidity or a certain type of chemical reaction.

7. Dr. S. M. Condren Indicators

8. Dr. S. M. Condren Neutralization Reactions acid + base ---> “salt” + water HCl + NaOH ---> NaCl + H 2 O

9. Dr. S. M. Condren Sulfur Acid SO 3 + H 2 O -----> H 2 SO 4

10. Dr. S. M. Condren Phosphoric Acid P 4 O 10(s) + 6H 2 O (l) ---> 4H 3 PO 4(aq)

11. Dr. S. M. Condren Strong vs. Weak Acids and Bases strong acid completely ionized weak acid partially ionized

12. Dr. S. M. Condren Which of the following "molecular" pictures best represents a concentrated solution of the weak acid HA with Ka = 10 -5 ? A, B

13. Dr. S. M. Condren Autoionization of Water H 2 O + H 2 O H 3 O + + OH - [H 3 O + ][OH - ] K = ----------------- [H 2 O] 2 K w = K [H 2 O] 2 = [H 3 O + ][OH - ] = 1.0 x 10 -14

14. Dr. S. M. Condren Autoionization of Water K w = K [H 2 O] 2 = [H 3 O + ][OH - ] = 1.0 x 10 -14 [H 3 O + ][H 3 O + ] = 1.0 x 10 -14 [H 3 O + ] 2 = 1.0 x 10 -14 [H 3 O + ] = 1.0 x 10 -7 -log([H 3 O + ]) = -log(1.0 x 10 -7 ) pH = -log([H 3 O + ]) = 7.00

15. Dr. S. M. Condren pH Scale @ -2 -----> @ +16 pH = - log [H 3 O + ]

16. Dr. S. M. Condren A solution with pH=5 is 100 times more acidic than a solution with a pH =? 7, 3, 0.05

17. Dr. S. M. Condren pH Scale