2.14.2 The Ozone Layer

Question 1

What are haloalkanes?

Answer 1

Alkanes with one or more H atom substituted by a halogen

Question 2

What do we call a haloalkane that contains chlorine and fluorine?

Answer 2

Chlorofluorocarbon (CFCs)

Question 3

What is ozone?

Answer 3

Ozone, O3, absorbs ultraviolet light and prevents it from reaching the ground

Question 4

How is ozone formed?

Answer 4

UV light from the sun provides the energy needed to break the O=O bond of oxygen
The radicals then react with oxygen to form ozone

Question 5

What happens when an ozone molecule absorbs UV light?

Answer 5

It dissociates to form an oxygen molecule and atom

Question 6

What has the release of CFCs caused to happen?

Answer 6

It has increased the rate of ozone decomposition, causing the concentration to decrease

Question 7

What are the three equations for decomposition of ozone due to CFCs?

Answer 7

CCl3F –UV light–> .CCl2F + .Cl
Cl. + O3 –> ClO. + O2
ClO. + O3 –> 2O2 + .Cl