Download Electrochemistry

Chapter 21.1

Electrochemistry occurs through the use of
spontaneous redox reactions

For any two metals in an activity series, the
more active metal is the more readily
oxidized.

Because metals have different activities of
oxidation, we can use this to do things like
electroplating…
Zinc is
more
readily
oxidized
than
copper.
Causing
the
copper
to plate
the zinc
kicking
off zinc
atoms.
As the
copper
replaces
the zinc
as a
solid, the
zinc
replaces
the
copper
sulfate
with zinc
sulfate.



All electrochemical processes involve redox
reactions.
An electrochemical process is any
conversion between chemical energy and
electrical energy.
An electrochemical cell is any device that
converts chemical energy into electrical
energy or electrical energy into chemical
energy.


This is an electrochemical cell
that converts chemical energy
to electrical energy.
Named after Italian physicist
Alessandro Volta.



Electrical energy is produced by a
spontaneous redox reaction.
Electrons flow and create a voltage.
Can measure using a voltmeter or use to run
a small motor or light a light bulb!

Redox Reaction:

2Ag+ + Cu  2Ag + Cu+2

Identify the electrodes (cathode and anode),
salt bridge, and electron flow.
 Galvanic

Cell = Voltaic Cell
Have you ever heard of galvanized metal?
◦ It is a metal coated with another metal.




What current technologies use
electrochemical processes to produce
electrical energy?
1) Dry Cells
2) Lead Storage Batteries
3) Fuel Cells


A dry cell is a voltaic cell in which the electrolyte is
a paste.
Both dry cells and alkaline batteries are single
electrochemical cells that produce about 1.5 V.


A battery is a group of cells connected
together. The half-reactions for a lead
storage battery are as follows.
A 12-V car battery consists of six voltaic
cells connected together. One cell of a
12-V lead storage battery is illustrated
here.


Are voltaic cells that have renewable
electrodes.
Electrical energy is continually obtained and
can be designed to emit no air pollution and
are more cost-effective.
The
hydrogenoxygen fuel
cell is a clean
source of
power. Such
cells are
often used in
spacecraft.



Build a simple voltaic cell with a partner.
Measure the voltage.
Maybe try hooking it to a motor or light
bulb??