CFCs and the ozone layer Flashcards
Where is the ozone layer found?
On the outer edge of the stratosphere
How is ozone formed?
O2 + UV -> 2O - broken down under UV radiation and O + O2 -> O3 - reacts with O2 molecules to form ozone
How is ozone broke down?
O3 + UV -> O2 + O
How does the ozone layer protect us?
It protects from UV radiation by absorbing it
What is the risk of the absence of the ozone layer?
There is an increased risk of genetic damage and skin cancer
What are CFCs?
Chlorofluorocarbon e.g. Freon-12
What are HCFCs?
Hydrochloroflourocarbon e.g. HCFC-22
What were CFCs used for?
Refrigerants and aerosol spray
Why do CFCs exist in the lower atmosphere?
C-F and C-Cl bonds are strong so molecules don’t break down easy
What does photodissociation produce?
Chlorine radicals
How do Cl radicals cause the break down of ozone?
Cl* + O3 -> ClO* + O2
ClO* + O -> Cl* + O2
O3 + O -> 2O2
What are chlorine radicals in the breakdown of ozone?
They act as a catalyst as they are unchanged at the end of the
Where does NO come from?
Lightening strikes and high flying aircraft’s
How does NO breakdown zone?
NO* + O3 -> NO2* + O2
NO2 + O -> NO* + O2
O3 + O -> 2O2
