1. Oxidation & Reduction

2. Monday 3/3/08 Prep: 1.Submit 20-1 & 20-2 for copies. 2.Clean up room. Class: DMA: Set all lab equipment on side counters. Schedule of Week (Pass papers while graphs checked) 1.Graphs shared up front for discussion of results using document viewer. 2.Lab report expectations reviewed. Asmt: Lab Report (written individually) due Tuesday. Plan: 1.Talk to POD about Rubric & Thursday. 2.Respond to tournament query. 3.Explore U12 & U11 brackets.

3. Schedule of Week 3/3-3/7/08 Mon – Review Lab Results / Asmt: INDIVIDUAL Lab Report due Tuesday Tues – Oxidation / Reduction / Worksheet 20-1 / Asmt: Page 665 #1-4, 669 #1-3 Wed – Analyzing Reactions / Worksheet 20- 2 / Asmt: Practice Exam 4 Thur – Review Unit 4 Fri – Unit 4 Exam (no school?)

4. Redox Side 8 Chapter 20 Voltaic Cells – Oxidation vs Reduction  Electricity! Chapter 23 Electrolytic Cells – Redox to Isolate Metals! Electrolysis of Water Demo Chapter 36 The Dry Cell? Chapter 10 Space Flight

5. Oxidation Numbers – 6 Rules 1.The oxidation # of a lone element is 0. 2.The oxidation # of a monatomic ion = its ionic charge. 3.Periodic patterns of elements include: Alkali metals = +1 alkaline earth metals = +2, Al is always +3, F is always -1, H is +1 if with non-metals, O is almost always -2. 4.Every element in a compound has an oxidation # for each atom. 5.The total of all the oxidation #s in a compound = 0. 6.The total oxidation #s in a polyatomic ion = the total charge.

6. 20-1 Examples 1. N 2 Ox# = 0 2. H 2 O Ox#s: H: +1, O: -2 3. NaCl Ox#s: Na: +1, Cl: -1 4. OH -1 Ox#s: O: -2, H: +1 Total: -2 +1 = -1 5. Fe Ox# = 0 6. Fe 2 O 3 Ox#s: O: -2 (x3) = -6 Fe +3 (x2)=+6 7.BaSO 4 Ox#s: Ba: +2, O: -2 (x4) = -8 S must be -6 to make total = 0

7. Definitions Oxidation – loss of electrons (LEO) Reduction – gain of electrons (GER) LEO says GER! Loss of Electrons is Oxidation, Gain of Electrons is Reduction Oxidizing Agent – Gains electrons to leave victim oxidized. (= electron thief) Reducing Agent – Donates electrons ands becomes oxidized (= victim).

8. 20-2 Example 1 Al + O 2  Al 2 O 3 a.Determine all oxidation numbers: b.Determine what became more positive since it lost electrons (oxidized) & what became more negative since it gained electrons (reduced). c.Determine which was the thief (oxidizing agent) & which was the victim (reducing agent). 0-2+3(x3) Al lost 3 electronsAl was oxidized O gained 2 electronsO was reduced Al was the victim Al is the reducing agent O was the thief!O is the oxidizing agent 0(x2)

9. 20-2 Example 2 Fe + CuCl 2  FeCl 2 + Cu a.Determine all oxidation numbers: b.Determine what became more positive since it lost electrons (oxidized) & what became more negative since it gained electrons (reduced). c.Determine which was the thief (oxidizing agent) & which was the victim (reducing agent). 0 +2 0 +2(x2) Fe lost 2 electronsFe was oxidized Cu gained 2 electronsCu was reduced Fe was the victim Fe is the reducing agent Cu was the thief! Cu is the oxidizing agent