1. UNIT 7:
Lesson 1: Introduction

2. The Electrochemical Cell
An electrochemical cell is a system that produces electrical energy from chemical energy.
Each half of the electrochemical cell is called a half-cell. The reaction that occurs in a half-cell is called a half-reaction.
This is just a brief intro – we will learn much more about electrochemical cells next unit, but first we must learn some theory...

3. Redox Reactions
An oxidation reaction is a half-reaction in which a species loses electrons.
A reduction reaction is a half-reaction in which a species gains electrons.
Just remember: LEO the lion says GER!
These two reactions always go hand-in-hand. The overall reaction involving the loss and gain of electrons is called a redox reaction.

4. Oxidation or Reduction?
A species being oxidized becomes more positively charged. (LEO → less negative = more positive.)
E.g. Zn → Zn e-.
A species being reduced becomes more negatively charged. (GER → more negative = less positive.)
E.g. Cu e- → Cu.

5. Brain Break!
Spot It!

6. Oxidizing and Reducing Agents
In the redox reaction 2 Ag+ + Cu → 2 Ag + Cu2+
Ag+ is the “agent” that causes Cu to be oxidized, so Ag+ is the oxidizing agent.
Cu is the “agent” that causes Ag+ to be reduced, so Cu is the reducing agent.
The oxidizing agent is reduced, and the reducing agent is oxidized!
Note: the reducing or oxidizing agent is the entire molecule, not just the atom.

7. Demo: Cereal Surprise!
Predict: What chemical can be easily extracted from breakfast cereal?
Observe: What did you see?
Explain: Iron metal (Fe) is put into cereal to react with the hydrochloric acid in our stomachs and provide the nutrient Fe2+:
Fe + 2 HCl → Fe Cl- + H2
Is the iron reduced or oxidized in the stomach?
Demo 12.V.2 – 15 min

8. Practice:
Pg. 192 #1 and 2
15 min