Electrochemistry

1
Electrochemistry

• Redox
• Oxidation / Reduction

2
Potato Clock
3
Leo Ger
My name is Leo. Grr-rrrr

• Lose electron ? oxidation
• Zn ? 2e- Zn2
• Gain electron ? reduction
• 2e- Cu2 ? Cu

4
Rules for assigning oxidation states
5
Redox Reaction
Zumdahl, Zumdahl, DeCoste, World of Chemistry
2002, page 591
6
Electron Flow
Zumdahl, Zumdahl, DeCoste, World of Chemistry
2002, page 592
7
Ion flow keeps the charge neutral
Zumdahl, Zumdahl, DeCoste, World of Chemistry
2002, page 592
8
The salt bridge contains a strong electrolyte
Zumdahl, Zumdahl, DeCoste, World of Chemistry
2002, page 592
9
The porous disk allows ion flow
Zumdahl, Zumdahl, DeCoste, World of Chemistry
2002, page 592
10
Schematic of a Battery
Zumdahl, Zumdahl, DeCoste, World of Chemistry
2002, page 593
11
Simple Battery
Kelter, Carr, Scott, Chemistry A Wolrd of Choices
1999, page 487
12
Redox of a Battery
Kelter, Carr, Scott, Chemistry A Wolrd of Choices
1999, page 487
13
Standard Electrode Potentials
14
Types of Batteries

• Lead
• Ni-cad
• Alkaline
• Rechargeable
• Mercury
• Lithium

15
One Cell of a Lead Battery
Zumdahl, Zumdahl, DeCoste, World of Chemistry
2002, page 595
16
The First Battery
Alessandro Volta (1745 1827)
Generate electricity by putting a layer of
cardboard soaked in brine between discs of
copper and zinc a voltaic cell. When he made a
pile of these cells, he increased the amount of
electricity generated. This was the first
battery a collection of cells.
Zinc disc
Copper disc
Newmark, CHEMISTRY, 1993, page 46
17
A Mercury Battery
Zumdahl, Zumdahl, DeCoste, World of Chemistry
2002, page 596
18
A Common Dry Cell Battery
Zumdahl, Zumdahl, DeCoste, World of Chemistry
2002, page 596
19
Electroplating
20
Cathodic Protection of an Underground Pipe
Zumdahl, Zumdahl, DeCoste, World of Chemistry
2002, page 598