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Slide 1 of 29 Chemistry 20.1. © Copyright Pearson Prentice Hall Slide 2 of 29 The Meaning of Oxidation and Reduction Salt on icy roads can make driving.

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Presentation on theme: "Slide 1 of 29 Chemistry 20.1. © Copyright Pearson Prentice Hall Slide 2 of 29 The Meaning of Oxidation and Reduction Salt on icy roads can make driving."— Presentation transcript:

1 Slide 1 of 29 Chemistry 20.1

2 © Copyright Pearson Prentice Hall Slide 2 of 29 The Meaning of Oxidation and Reduction Salt on icy roads can make driving safer, but the salt that clings to the metallic parts of cars can cause them to corrode or rust relatively quickly. This corrosion is one example of a chemical reaction called oxidation-reduction. You will learn about oxidation-reduction reactions. 20.1

3 © Copyright Pearson Prentice Hall Slide 3 of 29 The Meaning of Oxidation and Reduction > What Are Oxidation and Reduction? How is the gain or loss of oxygen in a chemical reaction linked to oxidation and reduction? 20.1

4 Slide 4 of 29 © Copyright Pearson Prentice Hall The Meaning of Oxidation and Reduction > What Are Oxidation and Reduction? The substance gaining oxygen is oxidized, while the substance losing oxygen is reduced. These reactions are called oxidation- reduction reactions and are also known as redox reactions. 20.1

5 © Copyright Pearson Prentice Hall Slide 5 of 29 The Meaning of Oxidation and Reduction > What Are Oxidation and Reduction? Oxygen and Redox A Bunsen burner oxidizes the methane in natural gas to carbon dioxide and water. 20.1

6 © Copyright Pearson Prentice Hall Slide 6 of 29 The Meaning of Oxidation and Reduction > What Are Oxidation and Reduction? Carbon is oxidized when charcoal burns. 20.1

7 © Copyright Pearson Prentice Hall Slide 7 of 29 The Meaning of Oxidation and Reduction > What Are Oxidation and Reduction? Iron is oxidized when it rusts. 20.1

8 Slide 8 of 29 © Copyright Pearson Prentice Hall The Meaning of Oxidation and Reduction > What Are Oxidation and Reduction? Electron Shift in Redox Reactions How is the gain or loss of electrons linked to oxidation and reduction? 20.1

9 Slide 9 of 29 © Copyright Pearson Prentice Hall The Meaning of Oxidation and Reduction > What Are Oxidation and Reduction? Losing electrons is oxidation. Gaining electrons is reduction. Oxidation is now defined to mean complete or partial loss of electrons or gain of oxygen. Reduction is now defined to mean complete or partial gain of electrons or loss of oxygen. 20.1

10 Slide 10 of 29 © Copyright Pearson Prentice Hall The Meaning of Oxidation and Reduction > What Are Oxidation and Reduction? Redox Reactions That Form Ions 20.1

11 Slide 11 of 29 © Copyright Pearson Prentice Hall The Meaning of Oxidation and Reduction > What Are Oxidation and Reduction? 20.1

12 Slide 12 of 29 © Copyright Pearson Prentice Hall The Meaning of Oxidation and Reduction > What Are Oxidation and Reduction? The substance that loses electrons is called the reducing agent. The substance that accepts electrons is called the oxidizing agent. 20.1

13 © Copyright Pearson Prentice Hall Slide 13 of 29

14 © Copyright Pearson Prentice Hall Slide 14 of 29

15 © Copyright Pearson Prentice Hall Slide 15 of 29

16 © Copyright Pearson Prentice Hall Slide 16 of 29 Practice Problems for Conceptual Problem 20.1 Problem Solving 20.1 Solve Problem 1 with the help of an interactive guided tutorial.

17 Slide 17 of 29 © Copyright Pearson Prentice Hall The Meaning of Oxidation and Reduction > What Are Oxidation and Reduction? Redox With Covalent Compounds 20.1

18 Slide 18 of 29 © Copyright Pearson Prentice Hall The Meaning of Oxidation and Reduction > What Are Oxidation and Reduction? 20.1

19 © Copyright Pearson Prentice Hall Slide 19 of 29 The Meaning of Oxidation and Reduction > Corrosion What happens to iron when it corrodes? 20.1

20 Slide 20 of 29 © Copyright Pearson Prentice Hall The Meaning of Oxidation and Reduction > Corrosion Iron, a common construction metal often used in the form of the alloy steel, corrodes by being oxidized to ions of iron by oxygen. 20.1

21 Slide 21 of 29 © Copyright Pearson Prentice Hall The Meaning of Oxidation and Reduction > Corrosion Resistance to Corrosion Aluminum resists corrosion because it forms a protective coating of aluminum oxide. 20.1

22 Slide 22 of 29 © Copyright Pearson Prentice Hall The Meaning of Oxidation and Reduction > Corrosion Controlling Corrosion Painting a surface protects it from corrosion. Chromium metal also serves as a protective coating. 20.1

23 Slide 23 of 29 © Copyright Pearson Prentice Hall The Meaning of Oxidation and Reduction > Corrosion Zinc blocks attached to the steel hull of this ship oxidize instead of the iron, preventing corrosion. 20.1

24 © Copyright Pearson Prentice Hall Slide 24 of 29 Section Quiz -or- Continue to: Launch: Assess students’ understanding of the concepts in Section 20.1 Section Quiz

25 © Copyright Pearson Prentice Hall Slide 25 of Section Quiz. 1.Choose the correct words for the spaces. During oxidation, an element _______ electrons. During reduction, an element ________ electrons. a.gains, loses b.loses, gains c.gains, donates d.gains, accepts

26 © Copyright Pearson Prentice Hall Slide 26 of Section Quiz. 2.Choose the correct words for the spaces. During reduction, a substance may _______ oxygen or ________ hydrogen. a.gain, lose b.lose, gain c.gain, gain d.lose, lose

27 © Copyright Pearson Prentice Hall Slide 27 of Section Quiz.. 3.The element that donates electrons in a redox reaction is called the reducing agent. This means the reducing agent is always a.the more active element. b.the less active element. c.oxidized. d.reduced.

28 © Copyright Pearson Prentice Hall Slide 28 of Section Quiz. 4.Which substance is the reducing agent in the following chemical reaction? Fe 2 O 3 + 3CO  2Fe + 3CO 2 a.Fe 2 O 3 b.CO c.Fe d.CO 2

29 © Copyright Pearson Prentice Hall Slide 29 of Section Quiz. 5.The following equations describe the corrosion of iron to iron hydroxides in moist conditions. 2Fe(s) + O 2 (g) + 2H 2 O(l)  2Fe(OH) 2 (s) 4Fe(OH) 2 (s) + O 2 (g) + 2H 2 O(l)  4Fe(OH) 3 (s) What substances in the equations are being oxidized? a.Fe(s) and Fe(OH) 2 (s) b.the O 2 (g) in both reactions c.the O 2 (g) and H 2 O(l) in both reactions d.Fe(OH) 2 (s) and Fe(OH) 3 (s)

30 END OF SHOW


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