Air And Atmosphere

Front 1

composition of air

78% nitrogen
21% oxygen
1% other gases such as noble gases argon and carbon dioxide

Back 1

I

Front 2

amount of water vapour in air vary around the world

Back 2

s

Front 3

Carbon monoxide is colourless and odourless

carbon monoxide is from incomplete combustion of petrol in car engines

Back 3

d

Front 4

sulfur dioxide is from the burning of fossil fuels such as crude oil ( petroleum) and natural gas . This is because these substances contain sulfur

sulfur + oxygen -> sulfur dioxide

sulfur dioxide can also be produced from volcanic eruptions

Back 4

h

Front 5

oxides of nitrogen

when temperature is high nitrogen combines w oxygen in air to form nitrogen monoxide

nitrogen monoxide then reacts w air to form a brown gas , nitrogen dioxide


during thunder storms heat energy released from lightning can cause nitrogen and oxygen in the air to react and form oxides like nitrogen monoxide or dioxide

Back 5

s

Front 6

unburnt hydrocarbons are released from car exhaust fumes and chemical plants

methan -> matter decay or cows and sheeps may give off methan due to digestion of food.

Or decay from rubbish in landfills

ozone is formed when nitrogen dioxide in air reacts w unburnt hydrocarbons in the presence of sunlight

Back 6

s

Front 7

effects

carbon monoxide -> Reacts with haemoglobin in the blood to form carboxyhaemoglobin , which reduces the ability of haemoglobin to transport oxygen to the rest of the body .

causing headaches , death , breathing difficulties

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sulfur dioxide and oxides of nitrogen -》

irritates eyes, lungs and causes breath difficulties

high levels can lead to inflammation in lungs (bronchitis )

reacts with water in the atmosphere to form acid rain , which corrdes buildings and harm aquatic life and plants

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unburnt hydrocarbons -》

cause cancer

react w nitrogen oxides to form ozone

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Methane - is a greenhouse gas , causes global warming

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ozone -》

forms photochemical smog , irritating eyes ,lungs and causes breathing difficulties

damages crops

Back 7

d

Front 8

How acid rain is formed :

- When acidic air pollutants such as sulfur dixoide and nitrogen dioxide react w water in the atmosphere

sulfur dioxide dissolves in water to form sulfurous acid H2SO3

in presence if oxygen it get oxidised to form sulfuric acid

also in the presence of oxygen and water nitrogen is converted to nitric acid

Back 8

Effects : sulfur and nitrogen dioxide are released into the atmosphere by factories and it reacts with water from the atmosphere forming acid rain

acid rain reacts with metals and carbonates like limestone and marble , causing buildings and bridges to be damaged

Acid rain leaches nutrients from the soil , causing plants to wither and die . Acid rain can also react with aluminium hydroxide present in soil to produce Al 3+ ions which are toxic to plants

acid rain reduces the ph value of natural water bodies , like lakes and streams , from 6.5 - 8.5 to below 4, which may be too acidic for fish or aquatic life to survive.

Front 9

ph value of unpolluted rainwater is usually slightly below 7 as carbon dioxide dissolves in water to form carbonic acid H2CO3

Back 9

c

Front 10

acid rain has a ph value of 4 or less

Back 10

g

Front 11

reducing effects of acid rain

powdered limestone calcium carbonate is use to neutralise the polluted lakes abd rivers

called liming

however expensive and effects are only temporary

Back 11

f

Front 12

catalytic converters

carbon monoxide + oxygen -》 carbon dioxide

nitrogen monoxide + carbon monoxide -》 nitrogen and carbon dioxide

octane and oxygen to form carbon dioxide and water vapour

Back 12

y

Front 13

flue gas desulfurisation

Back 13

- Minimising the effects of sulfur dioxide pollution

1 ) remove sulfur from fossil fuels before they are burnt . However , it is too expensive

2) Cheaper way : remove sulfur dioxide from waste gas formed when fossil fuels undergo combustion.

waste gas are called : flue gases

process of removing sulfur from sulfur dioxide is called Desulfurisation

Front 14

how

Back 14

sulfur dioxide is passed through calcium carbonate/calcium oxide . It reacts with calcium carbonate to form solid calcium sulfite( caso3) and carbon dioxide gas

calcium sulfite is further oxidised by atmospheric oxygen to form calcium sulfate

Front 15

ozone O3

- > filters harmful ultraviolet radiation from the sun , too much UV ray's can cause skin cancer , genetic mutations and eye damage - marine life as well

Back 15

one of the major causes of ozne depletion : chlorofluorocarbons

chloro-fluoro-carbons

CFC's - compounds containing elements of carbon , chlorine or florine

chlorine atoms react w ozone molecules in the stratosphere to form chlorine oxide and oxygen thus destroying the ozone layer .

In the presence of UV radiation , CFC's decompose to form chlorine atoms

ozone holes will be formed and UV radiation can reach the earth through there holes

Front 16

global warming : the atmosphere contains 0.03% volume of carbon dioxide

carbon cycle : Maintains the level of carbon dioxide in the atmosphere

Back 16

How is carbon dioxide added to the atmosphere ?

1) Respiration

glucose + oxygen ----> Carbon dioxide + water + energy

2) combustion of fuels

methane + oxygen ----> carbon dioxide + water vapour + heat energy

3) Decay and bacterial decomposition

- As dead animals and plants decay , bacterial breaks down the carbon compounds in them . Carbon dioxide is produced in the process

Front 17

How is carbon dioxide removed from the atmosphere ?

Back 17

1) Photosynthesis

Green plants convert carbon dioxide and water into glucose and oxygen

C02 + H2O -> C6H12O6 + O2

2) Ocean uptake

much of the dissolved carbon dioxide in the ocean is used up by plants and marine organisms.

Plants use the carbon dioxide to photosynthesis . Most of it is eventually formed into calcium carbonate to form shells.

The dead organisms settle to the seabed to form limestone

Front 18

Gases that trap radiation are called greenhouse gases

Back 18

Methane , nitrous oxide , Water vapour and carbon dioxide

carbon dioxide traps infrared radiation , reducing the amount of heat escaping into the atmosphere