Organohalogens

Question 1

Uses of organohalogen compounds

Answer 1

Molecules that contain at least 1 halogen joined to carbon chain
Pesticides
Not found in environment, not broken down by environment

Question 2

Ozone layer

Answer 2

Outer edge of stratosphere
Absorb most of UVB radiation
Depletion allows more to reach earth

Oxygen broken down into oxygen radicals and reformed by UV to form ozone at same rate

CFCs upset equilibrium

Question 3

CFCs and the ozone

Answer 3

CFCs are very stable, strong bonds
Less stable in stratosphere, broken down by UV, homolytic fission, radicals formed
CCl bond broken, lowest enthalpy

Question 4

Photodissociation

Answer 4

CF2Cl2 => CF2Cl +Cl *
Cl* + O3 => ClO* + O2
ClO* + O => Cl* + O2
O3 + O => 2O2

Question 5

Are CFCs responsible for all ozone depleting reactions

Answer 5

Nitrogen radicals are just as bad

NO* + O3 => NO2* + O2
NO2 + O => NO* + O2