ozone Flashcards
Give an example of a homogeneous catalyst
The Cl• radical in ozone depletion
What does the ozone layer do?
Doesn’t let through harmful UV-a rays
But it does let through UV-b and UV-c
What causes bond fission?
UV radiation
In the initiation stage, UV radiation causes homolytic fission etc.
When is ozone formed?
When oxygen gas absorbs high energy UV radiation
Show how oxygen gas forms ozone
O~2 –> 2O•
O~2 + O• O~3
What is the general equation for how ozone is removed?
O~3 + O –> 2O~2
What causes the ozone to be removed?
CFCs going up to the stratosphere from fridges
NO• from lightning and aircraft engines
How long do CFCs take to reach the ozone?
25 years
What is the equation for CFCs?
CF~2 Cl~2
show how CFCs remove ozone
Initiation:
CF~2 Cl~2 –> Cl• + CF~2 Cl
Propagation:
Cl• + O~3 –> ClO• + O~2
ClO• + O –> Cl• + O~2
Overall:
O~3 + O –> 2O~2
How many ozone molecules can 1 CFC remove?
100,000
Show how NO• removes ozone
We don’t need to know initiation here
Propagation:
NO• + O~3 –> NO~2• + O~2
NO~2• + O –> NO• + O~2
Overall:
O~3 + O –> 2O~2
What are all these reactions called?
Ones like O~3 + O –> 2O~2
Radical substitution reactions
What is the reaction from hexane to cyclohexane?
C~6 H~14 –>
C~6 H~12 + H~2
