CFCs (3.3.3-organic) Flashcards
What is Ozone?
O₃
Why is ozone useful?
Formed naturally and absorbs UV radiation
Why are CFC’s an issue with the ozone layer?
Cl atoms are formed in atmosphere when ultraviolet radiation causes C–Cl bonds in CFCs to break.
What CFC stand for?
Chlorofluorocabons
What is the role of Cl atoms in the depletion ozone layer?
Cl atoms catalyse the decomposition of ozone and leads to the hole in the ozone layer
Why have scientists changed their attitudes to CFCs changed?
- initial enthusiasm due to inertness, non-toxic & non-flammable
- Ozone depletion—-> presence of CFCs
- World community agreed that CFCs should be banned
What is the danger with UV light?
- Skin cancer (NOT global warming)
What uses did CFCs have?
- Refrigerants
- Bubbles in expanded polysterene
- Inert atmospheres
- Aerosol propellants
How doe ozone protect us? (equation)
O₃ + [UV] ——–> O₂ + O•
How is O₃ formed?
O₂ + [UV] ——–> 2O•
O• + O₂ ——-> O₃
CFC mechanism?
CFC ——-> •Cl + X
•Cl + O₂ ——-> •ClO + O₂
•ClO + O₃ ——–> •Cl + 2O₂
What does •Cl act as?
A catalyst since it’s reformed
