5.4 Halogen Derivatives

1. 5.4 Halogen Derivatives 5.4.1 Halogeno Compounds LO: I know a variety of uses for halogeno compounds

2. NAME STRUCTURE USE trichloromethane anaesthetic (chloroform) 1,1,1-trichloroethane solvent chloroethene manufacture of PVC (vinylchloride) manufacture of Teflon tetrafluoroethene LO: I know a variety of uses for halogeno compounds

3. 5.4.2 Chlorofluorocarbons LO: I understand the structure and properties of CFCs

4. Chlorofluorocarbons are based on alkane molecules where the hydrogens have been replaced by a mixture of chlorine and fluorine. dichlorodifluoromethane neutral insoluble unreactive non-flammable easily liquefied refrigerant long lasting propellant LO: I understand the structure and properties of CFCs

5. CFCs were used as refrigerants instead of ammonia and sulphur dioxide which are . toxic CFCs were used as propellants instead of propane and as they were not as dangerous (non-flammable). butane The use of CFCs was banned when it was discovered that they destroy . ozone LO: I understand the structure and properties of CFCs

6. 5.4.3 Ozone LO: I understand how CFCs cause a problem for the ozone layer.

7. uv Ozone provides a protective layer around the Earth against the damaging effects of radiation. uv UV radiation for the sun is responsible for the formation of in the upper atmosphere: ozone O2 O + O O + O2 O3 (ozone) UV radiation also splits CFCs in the upper atmosphere to produce atoms. chlorine Chlorine atoms react with , destroying it. ozone LO: I understand how CFCs cause a problem for the ozone layer.