Air Quality, Climate and Water Flashcards

1
Q

Which gas is most present in clean, dry air?

A

nitrogen

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2
Q

What is the composition of clean, dry air?

A

78% nitrogen
20% oxygen
1% water vapour
0.97% argon (among other inert gases)
0.03% carbon dioxide and others

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3
Q

How is carbon dioxide mainly formed?

A

complete combustion of carbon-containing fuels

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4
Q

How is carbon monoxide formed?

A

incomplete combustion of carbon-containing fuels

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5
Q

How are particulates (soot) formed?

A

incomplete combustion of carbon-containing fuels

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6
Q

How is methane formed (2 ways) ?

A

decomposition of vegetation
waste gases from digestion in animals

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7
Q

How are oxides of nitrogen formed?

A

nitrogen and oxygen in the air react in the HIGH TEMPERATURES of car engines

fala high temperatures

nao fala heat

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8
Q

How is sulfur dioxide formed?

A

combustion of fossil fuels that contain sulfur compounds

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9
Q

What are common air pollutants?

A

carbon dioxide
carbon monoxide
soot/particulates
oxides of nitrogen
sulfur dioxide
methane

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10
Q

What is the negative effect of carbon dioxide?

A

increases global warming, leads to climate change

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11
Q

What is the negative effect of carbon monoxide?

A

toxic gas, binds to haemoglobin in your blood and reduces capacity to carry oxygen

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12
Q

What is the negative effect of soot/particulates?

A

increases risk of cancer
increases risk of respiratory problems

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13
Q

What are the negative effects of nitrogen oxides?

A

acid rain
photochemical smog
respiratory problems

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14
Q

What is the negative effect of methane?

A

increases global warming, leads to climate change

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15
Q

What is the negative effect of sulfur dioxide?

A

acid rain

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16
Q

What are strategies to reduce the effects of climate change?

A

planting trees
reducing livestock farming
less use of fossil fuels
more use of hydrogen
renewable energy

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17
Q

What are strategies to reduce the effects of acid rain?

A

catalytic converters in vehicles
using low-sulfur fuels
use of flue gas + calcium oxide for desulfurisation

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18
Q

What is an obligatory product of incomplete combustion?

A

water

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19
Q

What other products, besides water, can be formed from incomplete combustion?

A

soot, carbon monoxide, carbon dioxide

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20
Q

What is the general word equation for complete combustion?

A

hydrocarbon + oxygen -> carbon dioxide + water

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21
Q

Which two products are always formed from complete combustion?

A

carbon dioxide and water

22
Q

What two ways do greenhouse gases (CO2 and methane) cause global warming?

A

they absorb, reflect and emit thermal energy
reduce the loss of thermal energy to space

23
Q

How do oxides of nitrogen form in car engines?

A

nitrogen and oxygen in air react in the heat of a car engine

24
Q

What happens to nitrogen oxides in a catalytic converter?

A

they are reduced

25
Q

Define ‘photosynthesis’.

A

the process which uses energy from light to convert water and carbon dioxide into oxygen and glucose in the presence of chlorophyll

26
Q

What is the word equation for photosynthesis?

A

carbon dioxide + water → glucose + oxygen

27
Q

What is the symbol equation for photosynthesis?

A

6CO2 + 6H2O → C6H12O6 + 6O2

28
Q

What are two tests to test the presence of water?

A

anhydrous cobalt (II) chloride
anhydrous copper (II) sulfate

29
Q

What happens to anhydrous copper(II) sulfate when it is in contact with water?

A

it goes from white to blue

30
Q

What happens to anhydrous cobalt (II) chloride when it is in contact with water?

A

it goes from blue to pink

31
Q

How do you test for water purity?

A

boil water, if it boils at 100 degrees it is pure
freeze water, if it freezes at 0 degrees it is pure

32
Q

Why is distilled water used in practical chemistry?

A

distilled water has less chemical impurities

33
Q

What potentially harmful substances can be found in water from natural sources?

A

some metal compounds
some plastics
sewage
nitrates and phosphates

34
Q

Which beneficial substances can be found in water from natural sources?

A

dissolved oxygen
some metal compounds

35
Q

Why are some plastics in water from natural sources harmful?

A

harm aquatic life

36
Q

Why is sewage in water from natural sources harmful?

A

has harmful microbes which can cause disease

37
Q

Why are nitrates and phosphates in water from natural sources harmful?

A

cause deoxygenation of water, damages aquatic life

38
Q

Why is dissolved oxygen in water from natural sources beneficial?

A

beneficial for aquatic life

39
Q

Why are some metal compounds in water from natural sources beneficial?

A

provide essential minerals for life

40
Q

What is the function of sedimentation and filtration in water treatment?

A

remove solids

41
Q

What is the use of carbon in water treatment?

A

removes smells and tastes

42
Q

What does chlorination do in water treatment?

A

kill microbes

43
Q

equation for what happens in the catalytic converter

A

2CO + 2NO -> 2CO2 + N2

44
Q

equation for formation of oxides of nitrogen

A

N2 + 2O2 -> 2NO2

45
Q

how catalytic converter reduces emissions of of pollutantants

A
  • carbon monoxide converted to carbon dioxide (2CO + O2 -> 2CO2)
  • oxides of nitrogen are reduced to nitrogen
  • hydrocarbons are burned to make water
  • products: carbon dioxide, water, nitrogen
46
Q

what is the pH of rain

A

5.6 (naturally acidic) as it mixes with solutes in the air

47
Q

when CO2 and other solutes dissolve in rainwater, what is formed?

A

carbonic acid

48
Q

formation of acid rain

A
  • some fossil fuels contain sulphuric impurities
  • when burnt sulfur react with oxygen, producing sulphuric dioxide
  • sulphuric dioxide dissolves in rainwater to make sulphuric acids which form acid rain
49
Q

problems with acid rain

A
  • dissolve limestone (buildings)
  • destroy vegetation
  • kill water lief due to changing a lake, river, etc
  • damage human skin
50
Q

ammonium salts and nitrates are used as

A

fertilisers

51
Q
A
52
Q

Describe the use of NPK fertilisers

A

provide the elements nitrogen, phosphorus and potassium for improved plant growth