Chemistry Reference
In-Depth Information
This protective ozone layer has undergone significant deterioration over
the past 30 years as a result of man-made chemicals that have been
released into the atmosphere. One of the most damaging groups of
chemical is the
chlorofluorocarbons,
, or CFCs. UV radiation causes chlorine
atoms to break free from CFC molecules. The free chlorine atoms react
with ozone, causing one oxygen atom to be removed from the molecule.
The reacted oxygen breaks free from chlorine and joins to another free
oxygen, forming O
2
instead of ozone (see Figure 2). The free chlorine
atoms remain in the atmosphere and continue to react with ozone for an
extended period of time. In this experiment, you will research the process
of ozone depletion and build a three-dimensional model demonstrating the
process of ozone depletion in the atmosphere.
F
F
C
1. UV radiation frees
a chlorine atom from CFC.
CFC molecule
Cl
C
Cl
Cl
Cl
Cl
Cl
ClO (chlorine
monoxide)
O
2
(oxygen
molecule)
Cl
O
O
O
Cl
Cl
O
O
Cl
O
O
O
O
O
free
chlorine
O
3
(ozone)
ClO (chlorine
monoxide)
O
2
(oxygen
molecule)
free
chlorine
free oxygen
from stratosphere
2. Free chlorine
atom collides with
ozone molecule.
3. One oxygen atom
is removed from ozone
to form chlorine monoxide.
4. Free oxygen collides
with chlorine monoxide.
5. Chlorine atom
is released.
Free chlorine atom continues the cycle.
Figure 2
Time Required
45 minutes
