1. Electrochemistry – Research Projects
2 or 3 PowerPoint slides
May use my background
Font - size 18 or 20 Tahoma
I have access to pictures in the book – just ask for them.
Sample questions to answer
What it is?
How does it work?
How is it related to electrochemistry?
Include in slides
Diagram(s)
Half reactions or cells
balanced equations
Due Date 11/13
Five minute (NO LONGER) presentation.
Topics:
Lead Storage Batteries 17.5
Dry Cell Batteries 17.5
Fuel Cells 17.5
NiCd Batteries 17.5
Photovoltaic cells 17.5
Galvanizing 17.6
Cathodic Protection 17.6
Hall Heroult Process 17.8
Electrorefining 17.8 e-

2. Introduction to Batteries and Corrosion
Electrochemistry
Introduction to Batteries and Corrosion
Chapter 17 Sections 5 & 6 e-

3. Electrochemistry- Batteries
A galvanic cell or group of galvanic cells connected in series
Potentials of individual cells = total battery potential
Direct current
Series vs. Parallell e-

4. Electrochemistry- Batteries
How are these connected?
Series
Two 1.5V , 2000mAH in series = 3.0V & 2000mAH
Parallel
Two 1.5V, 2000mAH in parallel = 1.5V & 4000mAH
What is going on here?
Four batteries, two pairs in series, pairs connected in parallel
3.0V & 4000mAH e-

5. Electrochemistry- Corrosion
Corrosion returns metals to their natural states, ores.
Oxidation of metal
Metals that are easily corroded have reduction potentials less than O2 (g)
Most metals develop a thin oxide coating – preventing further oxidation
Al E = -1.7V thin layer of Al2O3 or Al2(OH)6 E = -0.6 V
Fe forms a rust coating but it flakes off exposing more iron
Cu forms CuCO3 or green patina
Ag forms Ag2S or tarnish e-

6. Electrochemistry- Corrosion
Corrosion Mechanism of Steel
Steel has a non-uniform surface – not completely homogeneous
Anions, Fe2+, flow through the moisture to the cathode to react with oxygen gas
The moisture is the salt bridge; the metal is the “wire” for e- flow.
Fe2+ (aq) + O2 (g) + (4n+2n) H2O(l)  2Fe2O3•n H2O(s) H+(aq)
Different degrees of hydration produces various FexOy compounds with various colors – red, black yellow e-
p. .814

7. Electrochemistry- Corrosion
Corrosion Mechanism of Steel
NaCl or any salt accelerates corrosion
The salt dissolves in the moisture which increases conductivity
Cl1- forms many stable complexes with Fe3+ e-
p. .814