1. Monday, April 14, 2008 1.Chapter 17 Quiz 2. Notes Section 18.1 – Oxidation-Reduction 3. Homework – Reading Analysis – Section 18.1

2. Types of Reactions What were the types of reactions we talked about back in chapter 8? What were the types of reactions we talked about back in chapter 8? Precipitation Precipitation Acid-base Acid-base Combustion Combustion Synthesis Synthesis Decomposition Decomposition

3. Classify the reaction type for each of the following: Forest fire Forest fire Rusting steel Rusting steel Gasoline in car Gasoline in car Metabolism of food Metabolism of food Batteries Batteries All of these are types of oxidation/reduction reactions.

4. Oxidation What do you think happens in these reactions? What does the word sound like? What do you think happens in these reactions? What does the word sound like? Called oxidation because ‘O’ is added to element Called oxidation because ‘O’ is added to element Originally used to describe combustion- reaction of substances with oxygen in the air Originally used to describe combustion- reaction of substances with oxygen in the air When substances lost oxygen, they were reduced in mass  called reduction reactions When substances lost oxygen, they were reduced in mass  called reduction reactions

5. Metal/Nonmetal Reactions oo +1 -1 2Na(s) + Cl 2 (g)  2NaCl(s) Na e-  Cl  Na + Cl -

6. Drawing Recall how we drew this transfer of electrons. Recall how we drew this transfer of electrons. An electron is transferred from the sodium to the chlorine An electron is transferred from the sodium to the chlorine

7. Oxidation-Reduction Reactions Reactions in which one or more electrons are transferred Reactions in which one or more electrons are transferred Also called Redox reactions Also called Redox reactions Oxidation is defined as the loss of electrons Oxidation is defined as the loss of electrons Reduction is defined as the gain of electrons Reduction is defined as the gain of electrons

8. Oxidation / Reduction OIL RIG – Oxid. Is Loss, Reduc. Is Gain LEO the Lion goes GER – Lose Electrons Oxidation Gain Electrons Reduction

9. Oxidation / Reduction 4Fe + 3O 2  2Fe 2 O 3 What is oxidized? What is reduced? Zn + Cl 2  Zn 2+ + 2Cl - Practice Problem 18.1 2Cu + O 2  2CuO 2Cs + F 2  2CsF

10. Oxidation/Reduction Do metals gain or lose electrons? Do metals gain or lose electrons? Are they oxidized or reduced? Are they oxidized or reduced? Do some metals lose electrons more easily than others? Do some metals lose electrons more easily than others? If you put Cu(s) in Mg(NO 3 ) 2, will Cu lose e- and Mg gain them to become Mg? If you put Cu(s) in Mg(NO 3 ) 2, will Cu lose e- and Mg gain them to become Mg? –Which metal wants to get rid of e- more?

11. Will a Reaction Occur? Magnesium wants to get rid of electrons more so it won’t take them away from copper Magnesium wants to get rid of electrons more so it won’t take them away from copper How do we know? How do we know? Electronegativities page 403 Electronegativities page 403 Mg 1.2, Cu 1.9 Mg 1.2, Cu 1.9 How about Mg and Fe(NO 3 ) 2 ? How about Mg and Fe(NO 3 ) 2 ?