Atmospheric Chemistry Flashcards
Why do CFC molecules have long residence times in the lower atmosphere?
They are stable (unreactive). They are insoluble in water
What are CFC molecules?
Chlorofluorocarbons
Give a major use of CFC’s before their production was restricted in 1987
Used in food packaging, coolants in fridges, pressure in aerosol cans
Name the non metallic oxide that is associated with ozone destruction in the stratosphere
Nitric oxide
Give a source of nitric oxide
Electrical discharge from lightening or spark plugs
Write the balanced equation for the formation of ozone it the stratosphere
O3 - O2 + O
Write a balanced equation showing the photo dissociation of ozone
O2 + O - O3
State two effects of damage to the ozone layer
Skin cancer, temporary blindness from looking directly at the sun
Give one former major use of a CFC
Coolants in fridges
Give an example of a CFC
Dichlorodifluorocarbons
Identify the group of compounds now used as ozone friendly CFC replacements
HCFC’s hydrochlorofluorocarbons
What is a greenhouse gas
A gas in the atmosphere that absorbs heat and therefore contributes to global warming
What is an acidic oxide
An acidic gas with a pH of 0-6 i.e carbon dioxide
State 2 major ways by which human activities contribute to global warming
Air travel, land travel
What 3 chemical species form as a result of carbon dioxide gas dissolving in water?
Hydrogencarbonate ion, hydrogen ion, carbonate ion
Name a reagent used in scrubbers to remove acidic oxides
Ground limestone (calcium carbonate)
State one important way carbon dioxide is constantly added to the atmosphere
Burning fossil fuels
What use is made of the greenhouse factor of a gas
Assessing its influence on the greenhouse effect compared with other greenhouse gases
Name two other greenhouse gases
Water and Methane
Account for the inert nature of nitrogen gas
Nitrogen gas has a triple bond and is therefore unreactive
What is meant by nitrogen fixation?
Conversion of atmospheric nitrogen to useful nitrogen compounds that are chemically reactive.
State two ways by which nitrogen is fixed in nature
Lightening storms and photosynthetic battery
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
Spark plugs give off electrical discharge
N2+O2-2NO
2NO+O2-2NO2
Explain the term greenhouse effect
The greenhouse effect is the prevention of escape of infared radiation by gases in the atmosphere
