Atmospheric Chemistry

Question 0

Why do CFC molecules have long residence times in the lower atmosphere?

Answer 0

They are stable (unreactive). They are insoluble in water

Question 1

What are CFC molecules?

Answer 1

Chlorofluorocarbons

Question 2

Give a major use of CFC’s before their production was restricted in 1987

Answer 2

Used in food packaging, coolants in fridges, pressure in aerosol cans

Question 3

Name the non metallic oxide that is associated with ozone destruction in the stratosphere

Answer 3

Nitric oxide

Question 4

Give a source of nitric oxide

Answer 4

Electrical discharge from lightening or spark plugs

Question 5

Write the balanced equation for the formation of ozone it the stratosphere

Answer 5

O3 - O2 + O

Question 6

Write a balanced equation showing the photo dissociation of ozone

Answer 6

O2 + O - O3

Question 7

State two effects of damage to the ozone layer

Answer 7

Skin cancer, temporary blindness from looking directly at the sun

Question 8

Give one former major use of a CFC

Answer 8

Coolants in fridges

Question 9

Give an example of a CFC

Answer 9

Dichlorodifluorocarbons

Question 10

Identify the group of compounds now used as ozone friendly CFC replacements

Answer 10

HCFC’s hydrochlorofluorocarbons

Question 11

What is a greenhouse gas

Answer 11

A gas in the atmosphere that absorbs heat and therefore contributes to global warming

Question 12

What is an acidic oxide

Answer 12

An acidic gas with a pH of 0-6 i.e carbon dioxide

Question 13

State 2 major ways by which human activities contribute to global warming

Answer 13

Air travel, land travel

Question 14

What 3 chemical species form as a result of carbon dioxide gas dissolving in water?

Answer 14

Hydrogencarbonate ion, hydrogen ion, carbonate ion

Question 15

Name a reagent used in scrubbers to remove acidic oxides

Answer 15

Ground limestone (calcium carbonate)

Question 16

State one important way carbon dioxide is constantly added to the atmosphere

Answer 16

Burning fossil fuels

Question 17

What use is made of the greenhouse factor of a gas

Answer 17

Assessing its influence on the greenhouse effect compared with other greenhouse gases

Question 18

Name two other greenhouse gases

Answer 18

Water and Methane

Question 19

Account for the inert nature of nitrogen gas

Answer 19

Nitrogen gas has a triple bond and is therefore unreactive

Question 20

What is meant by nitrogen fixation?

Answer 20

Conversion of atmospheric nitrogen to useful nitrogen compounds that are chemically reactive.

Question 21

State two ways by which nitrogen is fixed in nature

Answer 21

Lightening storms and photosynthetic battery

Question 22

The concentration of NO2 in the atmosphere has increased in the past fifty years. Describe with the aid of chemical equations how an increase in the number of cars has contributed to this change

Answer 22

Spark plugs give off electrical discharge
N2+O2-2NO
2NO+O2-2NO2

Question 23

Explain the term greenhouse effect

Answer 23

The greenhouse effect is the prevention of escape of infared radiation by gases in the atmosphere

Question 24

Identify one gas in the atmosphere which makes a significant contribution to the greenhouse effect

Answer 24

Water, carbon dioxide, chlorofluorocarbons

Question 25

Mention one major way in which human activity contributes to carbon dioxide gas in the atmosphere

Answer 25

Burning fossil fuels i.e travel via cars, planes etc…

Question 26

Name a gas in the atmosphere which is not a greenhouse gas

Answer 26

Nitrogen

Question 27

State 3 consequences of increased greenhouse effect

Answer 27

Extinction of some species of animals, melting ice caps, increased water levels and over exposure to sun