atmospheric chemistry Flashcards Preview

LC Chemistry > atmospheric chemistry > Flashcards

Flashcards in atmospheric chemistry Deck (111)
Loading flashcards...

oxygen (the reactive gas)

-most reactive gas in air
-prep in lab by decomposition of hydrogen peroxide (H₂O₂)
-manufactured in industry by liquefaction followed by fractional distillation of air
-air turned into liquid + diff gases allowed to boil at diff temps


nitrogen (the unreactive gas)

--most abundant gas in air (78%)
-colourless, odourless, tasteless gas
-so unreactive bc of large amount of energy required to break triple bond between N atoms
-essential for plant growth (need to make proteins)
-so unreactive it cannot be used directly by plants


nitrogen fixation

conversion of atmospheric nitrogen to useful compounds


two methods of nitrogen fixation

-during thunderstorms/lightning
-nitrogen-fixing bacteria


during thunderstorms

-discharge of electricity that takes place during thunderstorms provides enough energy for nitrogen + oxygen in air to react together.
-substance called nitrogen monoxide, NO, formed
-ntrogen monoxide reacts w/ oxygen from air to form nitrogen dioxide
-nitrogen dioxide dissolves in rainwater to form nitrous acid, HNO₃


nitrogen-fixing bacteria

-plants called legumes (eg. peas, beans) have tiny root swellings containing rhizobium bacteria which can fix nitrogen
-not enough nitrogen fixed by natural processes to provide for out needs
-soils for growing crops must have fertiliser added
-fertiliser produced by artificial fixation (eg. Haber process)


nitrogen recycling

-nitrogen must be recycled throughout an ecosystem + returned to atmosphere
-bacteria called nitrifying + denitrifying bacteria necessary in process of recyling
-nitrogen cycle


inorganic carbon compounds

-carbon dioxide,
-carbon monoxide (CO),
-carbonate compounds,
- hydrogencarbonate compounds,


carbon burned in limited supply of oxygen

-if carbon burned in limited supply of oxygen, carbon monoxide formed instead of carbon diozide
eg. in car engines, in cigarette smoke


the carbon cycle

-percentage of carbon dioxide in atmosphere fairly constant at 0.03%
-some processes remove CO₂ from air, others return it to air


processes that remove CO₂ from air

6CO₂ + 6H₂O --> C₆H₁₂O₆ + 6O₂

-dissolving in rainwater, rivers, oceans, some of the CO₂ becomes incorporated into limestone


processes that return CO₂ to the air

-respiration by living things
-burning of fossil fuels
-roasting of limestone


the green house effect

Greenhouse gases: CO₂, water vapour

-greenhouse effect keeps the earth warm enough to live on


greenhouse factor

measure of the greenhouse effect (heat-absorbing properties) of a particular gas when compared with carbon dioxide


what gases are not greenhouse gases?



increase in greenhouse gases - carbon diozide

-human activities leading to inc in conc of greenhouse gases in air
-level of CO₂ giving cause for concern. Burning of of fossil fuels results in large amounts of CO₂ being added to air
-inc in rate at which CO₂ released into air not matched by rate at which it is removed by photosynthesis or by dissolving in oceans etc
-residence time of CO₂in air about 100 years


greenhouse gases

CFCs (chlorofluorocarbons)
dinitrogen oxide N₂O


methane - activity that is increasing its concentration

-increasing size of cattle herds - animals release large amount of methane from intestines
-growing of rice in paddy fields
-anaerobic breakdown of organic material in rubbish dumps


methane - residence time

10 years


CFCs (chlorofluorocarbons) - activity that is increasing its concentration

-propellant gas in aerosol sprays
-discarded fridges


CFCs (chlorofluorocarbons) - residence time

100 years


dinitrogen oxide N₂O - activity that is increasing its concentration

car exhaust fumes


dinitrogen oxide N₂O - residence time

100 years


enhanced greenhouse effect

-increasing concentrations of greenhouse gases in atmosphere may be leading to an "enhanced" greenhouse effect
-may bring about an increase in temp on surface of planet, referred to as global warming


potential implications of global warming

climate change
rise in sea level


climate change

-more extreme weather conditions will develop eg. severe storms, drought in some areas, flooding


rise in sea level

-extra heat may lead to melting of polar ice caps
-add to climate change + causes rise in sea level
-greatest increase in volume of water in sea will be as direct result of extra heat
-will lead to water in oceans expanding, leading to flooding of low-lying areas of planet


benefits of enhanced greenhouse effect

-increase in rate of photosynthesis in plants
would come about due to increase in carbon dioxide levels in air


strategies for bringing reversal of increase in CO₂

-developing alternative energy sources other than fossil fuels
-growing many more trees worldwide


atmospheric pollution

air pollution
acid rain