Atmospheric Chemistry Flashcards

1
Q

what is the atmosphere?

A

a layer of gases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

atmospheric composition: nitrogen

A

78%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

atmospheric composition: oxygen

A

21%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

how does oxygen exist

A

as oxygen gas O2

and ozone O3

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

manufacture of oxygen 2

A

extracted from the atmosphere by;

  • liquifying the air
  • fractionally distilling the air
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

manufacture of oxygen

first step

A

air is filtered to remove dust particles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

manufacture of oxygen

how is carbon dioxide removed?

A

air is passed through sodium hydroxide to remove CO2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

manufacture of oxygen

how is water removed?

A

water vapour condenses out during compression and in drying towers using silica gel

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

manufacture of oxygen

what occurs during compression

A

the air heats up

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

manufacture of oxygen

how to cool air

A

the air is passed through a heat exchanger where it is cooled by cold nitrogen in a fractioning column

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

manufacture of oxygen

in fractioning tower

A

liquified air is distilled, oxygen collects at he bottom and nitrogen at the top

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

manufacture of oxygen

why is oxygen further purified

A

purified to remove inert gases such as neon and krypton

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

4 uses of oxygen

A

steelmaking
welding
medicine
recreational

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

steelmaking - use of oxygen

A

to remove carbon, silicon and phosphorous from cast iron as there oxides

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

welding - use of oxygen

A

when ethyne is burned in oxygen temperatures of about 3000ºC are reached

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

how is nitrogen found?

A

as N2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

is nitrogen gas reactive or unreactive?

A

chemically unreactive due to the high bond energy of the triple bond between its atoms

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

why is nitrogen important

A

as it is a constituent of protein that is essential for muscle cells and blood cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Natural Fixation of Nitrogen

A

any process that produces useful compounds from atmospheric nitrogen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

3 natural fixation of nitrogen methods

A

lightning
bacteria
decomposition

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

how does lightning naturally fixate nitrogen?

A

at very high temperatures nitrogen and oxygen combine to form nitrogen monoxide, then combines with atmospheric oxygen to form nitrogen dioxide - dissolves in rain water to give nitrous and nitric acids, HNO2 and HNO3. fall on earth and deposited in soil, make plant protein

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

how does bacteria naturally fixate nitrogen?

A

certain species are capable of fixing atmospheric nitrogen into nitrates that plants can absorb to make plant proteins.
some are free in soil - Azotobacter, some in plants eg. clover and sweet pea - Rhizobium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

how does decomposition naturally fixate nitrogen?

A

most of the nitrates in soil come from dead and decaying plants and animals

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

an example of an artificial fertiliser

A

ammonium nitrate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

4 uses of nitrogen

A

freezing food
packaging of food
reduce the flammability of chemicals
manufacture of ammonia and nitric acid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

how does nitrogen help with freezing food?

A

liquid nitrogen is used to fast freeze foods which is less damaging to food than normal freezing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

how does nitrogen help with packaging food?

A

crisps are packed in nitrogen as it prevents oxidation of the oils

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

how does nitrogen reduce the flammability of chemicals?

A

nitrogen is used to reduce the oxygen content in storage tanks, thus reducing the flammability of certain chemicals
it is also used to flush out dangerous vapours in tanks

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

manufacture of ammonia

A

nitrogen is used as feedstock in the manufacture of ammonia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

equation for how lightning naturally fixates nitrogen

A

N2 + O2 -> 2NO

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

heat change of how lightning naturally fixates nitrogen

A

endothermic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

shape of CO2

A

linear

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

Combustion of carbon dioxide eqn.

A

C + O2 -> CO2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

carbon dioxide as an acid in water

A

CO2 + H2O -> H2CO3

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

H2CO3

A

carbonic acid (weak)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

what does aqueous carbon dioxide form?

A

an equilibrium mixture containing hydrogen ions, carbonate ions and hydrogen carbonate ions

37
Q

2 equations for equilibrium mixture containing hydrogen ions, carbonate ions and hydrogen carbonate ions

A

H2CO3 ⇌ H+ + HCO3-

H2CO3 ⇌ 2H+ + CO3 2-

38
Q

can carbonic acid be isolated as a single substance ?

A

no

39
Q

4 uses of carbon dioxide

A

carbonated drinks
fire extinguishers
cooling agent (dry ice)
in the manufacture of urea

40
Q

what type of fire would you put out with carbon dioxide?

A

electrical

41
Q

when is carbon monoxide formed?

A

if carbon is burned in a limited supply of oxygen

42
Q

formation of carbon monoxide eqn.

A

C + 1/2 O2 -> CO

43
Q

what type of oxide is carbon monoxide

A

neutral oxide - does not react with water

44
Q

why is CO poisonous

A

it deprives the body of oxygen

45
Q

where is CO present?

A

in cigarette smoke and car exhaust fumes

46
Q

fermentation of glucose equation

A

C6H12O6 -> 2C2H5OH + 2CO2

47
Q

enzyme for fermentation of glucose

A

zymase

48
Q

greenhouse gasses

A

gases in the atmosphere that absorb infra-red radiation from the sun

49
Q

examples of greenhouse gases

A
carbon dioxide
methane 
water vapour
nitrous oxide
ozone 
CFCs
50
Q

how much of the atmosphere is CO2

A

0.035%

51
Q

most abundant greenhouse gas

A

CO2

52
Q

what accounts for the increase in CO2

A

burning of fossil fuels and deforestation

53
Q

what reduces CO2

A

absorbed by oceans

54
Q

what accounts for more water vapour

A

global warming

55
Q

what can help to block sun rays

A

in increase of water in clouds

56
Q

concentration of methane in atmosphere

A

1.7 ppm

57
Q

why is there an increase in methane

A
waste from homes 
cattle populations
swamps, bogs and paddy fields 
aerobic fermentation 
trapped in ice - melting
58
Q

how effective is methane

A

20 times more effective than CO2

59
Q

how effective are CFCs

A

40 times more effective than CO2

60
Q

problem with CFCs

A

the breakdown of CFCs in the atmosphere release chlorine radicals that break up the ozone layer

61
Q

what is the ozone layer responsible for?

A

for protecting the earth from uv radiation

62
Q

residence time of CO2

A

50 to 200 years

63
Q

residence time of methane

A

10 years

64
Q

residence time of CFCs

A

50 to 100 years

65
Q

4 possible implications of the increased greenhouse effect

A

rise in sea levels
extinction of some plants
increase in levels of CO2 and methane
disruption to agriculture

66
Q

3 sources of air pollution

A

domestic
industrial
vehicles

67
Q

describe domestic pollution

A

fuels contain sulfur and carbon and when burned from sulfur dioxide and carbon dioxide. SO2 dissolves in water to produce acid rain, which kills vegetation and damages buildings, increased CO3 cause an increase in global temperature. smoke and dust particles are produced which cause smog which blackens buildings and can cause respiratory problems

68
Q

describe industrial pollution

A

the fuels used in industry e.g. oil and natural gase, release sulfur dioxide and carbon dioxide

69
Q

describe vehicle pollution

A

exhaust fumes produce unburned hydrocarbons, carbon monoxide and the oxides of nitrogen and lead
nitrogen monoxide and nitrogen dioxide cause acid rain and respiratory problems. Leas and its compounds are toxic and affect the brain. (catalytic converters)

70
Q

when is acid rain caused

A

when gases such as carbon dioxide, nitrogen dioxide and sulfur dioxide dissolve in water to form carbonic acid (H2CO3), nitrous acid (HNO2) and sulfurous acid (H2SO3)

71
Q

effects of acid rain on the environment

A
corrosion of buildings
reduction of crop yield
extinction of some plants 
leaching of heavy metals from soil 
reduction of fish numbers when snow melts into water
72
Q

3 preventative measures against acid rain

A

reduction in use of fossil fuels
use of catalytic converters
scrubbing of waste gases using limestone to remove pollutants from waste gases

73
Q

ozone

A

triatomic form of oxygen, O3

74
Q

describe ozone

A

a pale blue gas that is pleasant at low concentrations but is toxic at high concentrations and damages plant life

75
Q

significance of ozone layer

A

ozone protects life on earth from ultra-violet radiation

76
Q

formation of ozone

A

ultra-violet radiation breaks up oxygen molecules into oxygen free radicals, they then combine with molecules of oxygen to form ozone

77
Q

formation of ozone eqn.

A

O2 -> 2O•

O• + O2 -> O3

78
Q

photodissociation of ozone

A

destroyed by uv light

constantly being formed and broken up, usually at a steady rate

79
Q

photodissociation of ozone eqn.

A

O3 -> O2 + O•

80
Q

uses of CFCs

A

solvents in dry-cleaning
refrigerators and air conditioning - coolants
aerosols

81
Q

stratosphere

A

upper atmsophere

82
Q

eqn. for breakdown of CFCs in the stratosphere

A

n

83
Q

removal of ozone

A

reactive chlorine atoms break up ozone to form oxygen and chlorine monoxide, that reacts when oxygen to form chlorine

84
Q

equation for removal of ozone

A

Cl• + O3 -> ClO + O2

ClO + O• -> Cl• + O2

85
Q

i single chlorine atom

A

can destroy 1 million ozone molecules

86
Q

oxygen atoms destroying ozone eqn.

A

O• + O3 -> 2O2

87
Q

nitrogen monoxide destroying ozone

A

NO + O3 -> NO2 + O2

88
Q

eqn. for methane absorbing chlorine

A

CH4 + 2Cl -> CH3Cl + HCl