Ozone

Question 1

What is the troposphere ?

Answer 1

• layer of atmosphere closest to Earths surface

Question 2

What is the stratosphere?

Answer 2

• next layer above troposphere
• ozone layer is found

Question 3

What are the gases in the atmosphere and how much do they make up?

Answer 3

• N2 = 78%
• O2 = 21%
• remainder is a mix of CO2, CH4 , Ar and many other gases

Question 4

Why is ozone necessary in the stratosphere?

Answer 4

• filter out most harmful UV rays

Question 5

What happens when ozone is present in the troposphere?

Answer 5

• atmospheric pollutant
• causing photochemical smog

Question 6

How do you convert ppm to %?

Answer 6

• /10,000

Question 7

How do you convert % to ppm?

Answer 7

• x10,000

Question 8

What is the principle radiation of the earth and sun?

Answer 8

• UV , visible and infrared rays reach the earth from the sun
• the earth then reradiates the infrared radiation

Question 9

Describe the wavelength , energy and frequency of UV?

Answer 9

• wavelength = shortest
• frequency = highest
• energy = highest

Question 10

Describe the wavelength , energy and frequency of infrared radiation?

Answer 10

• wavelength = longest
• frequency = lowest
• energy = lowest

Question 11

What does microwave radiation correspond to?

Answer 11

• the energy required to make the molecule rotate

Question 12

What does infrared radiation correspond to?

Answer 12

• the energy required to make bonds vibrate

Question 13

What does UV and visible light correspond to?

Answer 13

• the energy required to make changes to an electron within an atom/ molecule

Question 14

How can UV and visible light make changes to electron?

Answer 14

• can promote electrons to higher electron shells / energy levels by making them ‘ excited’
• provide enough energy to break bonds ( photodissociation)
• ionise an atom

Question 15

Calculation for speed of light?

Answer 15

• frequency x wavelength

Question 16

Calculation for energy?

Answer 16

• frequency x Planck’s constant

Question 17

Describe homolytic fission

Answer 17

• non polar bonds
• result in 2 radicals
• one electron goes to each atom
• half curly arrows

Question 18

Describe heterolytic fission

Answer 18

• polar bonds
• result in 2 ions both electrons go to more electronegative atom

Question 19

What is a radical?

Answer 19

• a species with at least one unpaired pair of electrons

Question 20

What are the stages in a radical chain reaction?

Answer 20

• initiation
• propagation 1
• propagation 2
• major termination
• minor termination

Question 21

What happens during initiation?

Answer 21

• formation of free radicals by homolytic fission