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Flashcards in atmospheric chemistry Deck (111)
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1

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

2

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

3

nitrogen fixation

conversion of atmospheric nitrogen to useful compounds

4

two methods of nitrogen fixation

-during thunderstorms/lightning
-nitrogen-fixing bacteria

5

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

6

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)

7

nitrogen recycling

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

8

inorganic carbon compounds

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

9

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

10

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

11

processes that remove CO₂ from air

-photosynthesis
6CO₂ + 6H₂O --> C₆H₁₂O₆ + 6O₂

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

12

processes that return CO₂ to the air

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

13

the green house effect

Greenhouse gases: CO₂, water vapour

-greenhouse effect keeps the earth warm enough to live on

14

greenhouse factor

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

15

what gases are not greenhouse gases?

nitrogen
oxygen

16

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

17

greenhouse gases

methane
CFCs (chlorofluorocarbons)
dinitrogen oxide N₂O

18

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

19

methane - residence time

10 years

20

CFCs (chlorofluorocarbons) - activity that is increasing its concentration

-propellant gas in aerosol sprays
-discarded fridges

21

CFCs (chlorofluorocarbons) - residence time

100 years

22

dinitrogen oxide N₂O - activity that is increasing its concentration

car exhaust fumes

23

dinitrogen oxide N₂O - residence time

100 years

24

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

25

potential implications of global warming

climate change
rise in sea level

26

climate change

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

27

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

28

benefits of enhanced greenhouse effect

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

29

strategies for bringing reversal of increase in CO₂

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

30

atmospheric pollution

air pollution
acid rain