1. Slide 1 of 35 Chemistry 19.1

2. © Copyright Pearson Prentice Hall Slide 2 of 35 Acid-Base Theories Bracken Cave, near San Antonio, Texas, is home to twenty to forty million bats. Visitors to the cave must protect themselves from the dangerous levels of ammonia in the cave. Ammonia is a byproduct of the bats’ urine. You will learn why ammonia is considered a base. 19.1

3. © Copyright Pearson Prentice Hall Acid-Base Theories > Slide 3 of 35 Acid-Base Theories > > Properties of Acids and Bases What are the properties of acids and bases? 19.1

4. Slide 4 of 35 © Copyright Pearson Prentice Hall Acid-Base Theories > > > Properties of Acids and Bases Acids Acids taste sour, will change the color of an acid-base indicator, and can be strong or weak electrolytes in aqueous solution. 19.1

5. Slide 5 of 35 © Copyright Pearson Prentice Hall Acid-Base Theories > > > > > > Properties of Acids and Bases Citrus fruits contain citric acid. Tea contains tannic acid. 19.1

6. Slide 6 of 35 © Copyright Pearson Prentice Hall Acid-Base Theories > > > Properties of Acids and Bases Bases Bases taste bitter, feel slippery, will change the color of an acid-base indicator, and can be strong or weak electrolytes in aqueous solution. 19.1

7. Slide 7 of 35 © Copyright Pearson Prentice Hall Acid-Base Theories > > > > > > Properties of Acids and Bases Antacids use bases to neutralize excess stomach acid. The base calcium hydroxide is a component of mortar. 19.1

8. Slide 8 of 35 © Copyright Pearson Prentice Hall Acid-Base Theories > > > Arrhenius Acids and Bases How did Arrhenius define an acid and a base? 19.1

9. © Copyright Pearson Prentice Hall Slide 9 of 35 Acid-Base Theories > > > Arrhenius Acids and Bases Arrhenius said that acids are hydrogen- containing compounds that ionize to yield hydrogen ions (H + ) in aqueous solution. He also said that bases are compounds that ionize to yield hydroxide ions (OH – ) in aqueous solution. 19.1

10. Slide 10 of 35 © Copyright Pearson Prentice Hall Acid-Base Theories > > > > > > 19.1 Arrhenius Acids and Bases Hydrochloric Acid

11. Slide 11 of 35 © Copyright Pearson Prentice Hall Acid-Base Theories > > > > > > Arrhenius Acids and Bases Arrhenius Acids Acids that contain one ionizable hydrogen, such as nitric acid (HNO 3 ), are called monoprotic acids. Acids that contain two ionizable hydrogens, such as sulfuric acid (H 2 SO 4 ), are called diprotic acids. Acids that contain three ionizable hydrogens, such as phosphoric acid (H 3 PO 4 ) are called triprotic acids. 19.1

12. Slide 12 of 35 © Copyright Pearson Prentice Hall Acid-Base Theories > > > > > > Arrhenius Acids and Bases 19.1

13. Slide 13 of 35 © Copyright Pearson Prentice Hall Acid-Base Theories > > > > > > Arrhenius Acids and Bases Arrhenius Bases Hydroxide ions are one of the products of the dissolution of an alkali metal in water. 19.1

14. Slide 14 of 35 © Copyright Pearson Prentice Hall Acid-Base Theories > > > > > > Arrhenius Acids and Bases 19.1

15. Slide 15 of 35 © Copyright Pearson Prentice Hall Acid-Base Theories > > > > > > Arrhenius Acids and Bases Milk of magnesia is a base used as an antacid. 19.1

16. © Copyright Pearson Prentice Hall Acid-Base Theories > Slide 16 of 35 Acid-Base Theories > > Brønsted-Lowry Acids and Bases What distinguishes an acid from a base in the Brønsted-Lowry theory? 19.1

17. © Copyright Pearson Prentice Hall Slide 17 of 35 Acid-Base Theories > > > Brønsted-Lowry Acids and Bases The Brønsted-Lowry theory defines an acid as a hydrogen-ion donor, and a base as a hydrogen-ion acceptor. 19.1

18. Slide 18 of 35 © Copyright Pearson Prentice Hall Acid-Base Theories > > > > > > Brønsted-Lowry Acids and Bases Why Ammonia is a Base 19.1

19. Slide 19 of 35 © Copyright Pearson Prentice Hall Acid-Base Theories > > > > > > Brønsted-Lowry Acids and Bases Conjugate Acids and Bases A conjugate acid is the particle formed when a base gains a hydrogen ion. A conjugate base is the particle that remains when an acid has donated a hydrogen ion. 19.1

20. Slide 20 of 35 © Copyright Pearson Prentice Hall Acid-Base Theories > > > > > > Brønsted-Lowry Acids and Bases A conjugate acid-base pair consists of two substances related by the loss or gain of a single hydrogen ion. A substance that can act as both an acid and a base is said to be amphoteric. 19.1

21. Slide 21 of 35 © Copyright Pearson Prentice Hall Acid-Base Theories > > > > > > Brønsted-Lowry Acids and Bases 19.1

22. Slide 22 of 35 © Copyright Pearson Prentice Hall Acid-Base Theories > > > > > > Brønsted-Lowry Acids and Bases A water molecule that gains a hydrogen ion becomes a positively charged hydronium ion (H 3 O + ). 19.1

23. © Copyright Pearson Prentice Hall Acid-Base Theories > Slide 23 of 35 Acid-Base Theories > > Lewis Acids and Bases How did Lewis define an acid and a base? 19.1

24. © Copyright Pearson Prentice Hall Slide 24 of 35 Acid-Base Theories > > > Lewis Acids and Bases Lewis proposed that an acid accepts a pair of electrons during a reaction, while a base donates a pair of electrons. 19.1

25. Slide 25 of 35 © Copyright Pearson Prentice Hall Acid-Base Theories > > > > > > Lewis Acids and Bases A Lewis acid is a substance that can accept a pair of electrons to form a covalent bond. A Lewis base is a substance that can donate a pair of electrons to form a covalent bond. 19.1

26. © Copyright Pearson Prentice Hall Slide 26 of 35 Acid-Base Theories > Lewis Acids and Bases Animation 25 Compare the three important definitions of acids and bases.

27. Slide 27 of 35 © Copyright Pearson Prentice Hall Acid-Base Theories > > > > > > Lewis Acids and Bases 19.1

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31. © Copyright Pearson Prentice Hall Slide 31 of 35 Practice Problems for Conceptual Problem 19.1 Problem Solving 19.1 Solve Problem 1 with the help of an interactive guided tutorial.

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