10. air Flashcards

1
Q

composition of air

A
  • 78% nitrogen
  • 21% oxygen
  • 0.03% carbon dioxide
  • <1% other gases (group 0 noble gases)
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2
Q

common atmospheric pollutants

A
  • carbon monoxide
  • nitrogen monoxide + nitrogen dioxide
  • sulfur dioxide
  • methane gas
  • unburnt hydrocarbons
  • carbon dioxide
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3
Q

carbon monoxide:

source

A
  • incomplete combustion of carbon containing fuels
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4
Q

carbon monoxide:

effects on humans

A
  • toxic to humans
  • binds to haemoglobin in RBCs to form carboxyhaemoglobin
  • irreversible reaction, reduces ability of RBCs to transport oxygen
  • death
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5
Q

carbon monoxide:

solutions

A
  • removed by reactions in catalytic converters in vehicles

- CO + O2 = CO2

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6
Q

nitrogen monoxide + nitrogen dioxide:

source

A
  • lightning activities
  • in internal combustion engines
  • high temperature causes nitrogen and oxygen in the atmosphere to react
  • nitrogen monoxide can oxidise easily to form nitrogen dioxide
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7
Q

nitrogen monoxide + nitrogen dioxide:

effects on environment

A
  • nitrogen monoxide: neutral
  • nitrogen dioxide: acidic gas
  • dissolves in rainwater to form nitrous acid, oxidised to form nitric acid
  • acid rain
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8
Q

impacts of acid rain

A
  • corrodes buildings made of cement, reactive metals and limestone
  • decreases pH in soils, unsuitable for growing crops, reducing crop yield
  • may fall into rivers and lakes, decreasing pH of water and affecting plants + marine life
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9
Q

nitrogen monoxide + nitrogen dioxide:

effects on humans

A
  • poisonous choking gas that irritates and attacks the lungs

- respiration problems

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10
Q

nitrogen monoxide + nitrogen dioxide:

solutions

A
  • removed by reactions in catalytic converters in internal combustion engines
  • decomposes in a redox reaction to form N2 and O2
  • NO can react with CO to form CO2 and H2O
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11
Q

sulfur dioxide:

source

A
  • volcanic eruptions

- incomplete combustion of fossil fuels in internal combustion engines

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12
Q

sulfur dioxide:

effects on environments

A
  • acidic oxide
  • dissolves in water to form sulfurous acid, which oxidises to form sulfuric acid
  • acid rain
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13
Q

impacts of acid rain

A
  • corrodes buildings made of cement, reactive metals and limestone
  • decreases pH of soil, unsuitable for growing crops, reducing crop yield
  • may fall into rivers or lakes, affecting pH of water and plant/marine life
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14
Q

sulfur dioxide:

effects on humans

A
  • poisonous choking gas that irritates and attacks the lungs
  • respiratory problems
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15
Q

sulfur dioxide:

solutions

A
  • removed in flue glue desulfurisation to reduce liberation of sulfur dioxide gas
  • flue glue: waste gas from combustion of fossil fuels
  • sulfur dioxide + water = sulfurous acid
  • moist calcium carbonate + sulfurous acid = calcium sulfite + carbon dioxide + water
  • calcium sulfite + oxygen = calcium sulfate
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16
Q

methane gas:

effects on environment

A
  • greenhouse gas

- traps infrared radiation, contributes to global warming

17
Q

impacts of global warming

A
  • melting of large quantities of ice in the north and south pole, sea level rise, flooding in low lying countries
  • areas of land with vegetation become deserts, reducing crop yield
  • high temperatures drive out carbon dioxide from the oceans, (ghg) increased concentration in atmosphere, vicious cycle
18
Q

unburnt hydrocarbons:

source

A
  • from the incomplete combustion of hydrogen containing substances in internal combustion engines
19
Q

unburnt hydrocarbons:

effects on environment/humans

A
  • results in photochemical reactions which produce ozone

- difficulty breathing

20
Q

unburnt hydrocarbons:

solutions

A
  • removed by reactions in catalytic converters in vehicles
21
Q

carbon dioxide

A
  • continuously produced and removed
  • produced by: respiration, combustion
  • removed by: photosynthesis
  • maintained by the carbon cycle
22
Q

impacts of carbon dioxide

A
  • green house has
  • traps infrared radiation, results in global warming
  • impacts of global warming (refer to methane gas)
23
Q

ozone

A
  • ozone layer acts as a filter, prevents excess UV radiation from the sun from reaching the earth’s surface
24
Q

depletion of ozone layer

A
  • CFCs (chlorofluorocarbons) are used as propellants in aerosol sprays, and coolants in fridges/air cons
  • usually unreactive at sea level
  • when they move up to the stratosphere, decomposes under strong UV radiation to form chlorine atoms
25
Q

effect of chlorine atoms

A
  • chlorine atoms react with ozone layer to form oxygen molecules, creating holes in the ozone
  • chlorine atoms are regenerated, process is capable of occurring repeatedly
26
Q

equation

A

Cl + O3 = ClO + O2

ClO + O3 = Cl + 2O2

27
Q

impacts of depletion of ozone layer

A
  • depletion of ozone layer allows excess UV radiation from the sun to reach the surface of the earth
  • drastic increase in skin cancer, genetic mutations and eye damage (cataracts)