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Y4 Chemistry > Air > Flashcards

Air Flashcards

1
Q

What is the volume composition of (clean, dry) air?

A

O2: 21%
N2: 78%
CO2: 0.03%
Rare gases (mainly Argon):1%

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2
Q

What are some common atmospheric pollutants? (7)

A 
Carbon Monoxide (CO)
Methane (CH4)
Nitrogen Oxides (NO, NO2)
Sulfur Dioxide (SO2)
Ozone (O3)
Unburnt hydrocarbons
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3
Q

Is CO2 a pollutant?

A

No, it already occurs naturally in the atmosphere

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4
Q

Where does carbon monoxide (CO) come from?

A

Carbon monoxide is the product of incomplete combustion of carbon-containing substances (ie. petrol & ethanol)

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5
Q

What are the effects of carbon monoxide?

A

The poisonous nature of carbon monoxide causes harm to human health. It binds irreversibly with haemoglobin and reduces the cells’ ability to transport oxygen around the body.

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6
Q

How is carbon monoxide removed?

A

Carbon monoxide is removed by the reactions in the catalytic converters in vehicles.

  • Carbon monoxide reacts with oxygen in a redox reaction to form carbon dioxide
  • uses catalysts such as platinum and rhodium
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7
Q

Where do nitrogen oxides come from?

A

They are produced during lightning activities as well as from internal combustion engines due to very high temperatures, which allow oxygen and nitrogen to reach

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8
Q

What are the effects of nitrogen (di)oxide and sulfur dioxide?

A

*NO easily oxidized to NO2, which is acidic.

  • acidic oxide which forms acid rain
  • poisonous and choking gas that irritates the lungs and causes respiration problems
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9
Q

How does nitrogen dioxide become acid rain?

A

Nitrogen dioxide dissolves in rainwater and is oxidized by atmospheric oxygen to form nitric acid

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10
Q

How are nitrogen oxides removed?

A

Nitrogen dioxide is removed by the reactions in catalytic converters in vehicles.

  • can be decomposed to form nitrogen and oxygen
  • can react with carbon monoxide (CO) to form nitrogen (N2) and carbon dioxide (CO2)
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11
Q

Where does sulfur dioxide come from?

A

It is a product of volcanic eruptions and the combustion of fossil fuels (ie. coal)

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12
Q

How does sulfur dioxide form acid rain?

A

Sulfur dioxide dissolves in rainwater to form sulfurous acid, which is oxidized by atmospheric oxygen to form sulfuric acid

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13
Q

Why is acid rain undesirable?

A
  • Acid rain corrodes buildings made of cement, reactive metals, and limestone
  • It also decreases the pH in soil, making it unsuitable to grow crops
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14
Q

How is the effect of acid rain on crops mitigated?

A

Usage of calcium carbonate to reduce the effects of acid rain on soil pH
CaCO3- CaCO4

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15
Q

How is Sulfur dioxide removed?

A

Moist calcium carbonate is used in flue gas (waste gas) desulfurization to remove the liberation of SO2.

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16
Q

Which gases are removed by catalytic converters?

A

Carbon (C), Carbon monoxide (CO), Nitrogen oxides, Unburnt hydrocarbons

17
Q

What do catalytic converters do?

A

They convert pollutants produced from the combustion of fuel into less harmful substances (CO2, H2O, N2)

18
Q

Why is the ozone layer important?

A

It acts as a filter to remove excess harmful UV radiation from the sun

19
Q

How is the ozone layer depleted?

A

CFCs (Chlorofluorocarbons) move up to the stratosphere and decompose under strong UV radiation, forming chlorine atoms that destroy ozone. The ozone becomes oxygen molecules, creating holes in the ozone layer.

20
Q

Why is the depletion of the ozone layer dangerous?

A

It would allow excess UV radiation to reach the surface of the earth, possibly causing skin cancer, genetic mutation, and eye damage

21
Q

How are the different processes are involved in the carbon cycle?

A

Carbon dioxide is produced through combustion and respiration and is removed through photosynthesis

22
Q

How does the carbon cycle regulate the amount of carbon dioxide in the atmosphere?

A

Photosynthesis decreases the amount of CO2 in the air produced by respiration and combustion through recycling it. This regulates and maintains the amount of CO2 in the atmosphere.

23
Q

What are greenhouse gases and how do they affect the environment?

A

Greenhouse gases trap infrared radiation which contributes to global warming

24
Q

What are some greenhouse gases and where do they come from?

A
  • Methane (Decay of plant & animal matters)

- Carbon dioxide (respiration & combustion)

25
Q

What are some possible consequences of global warming?

A
  • Melting of large quantities of ice in the North Pole and the South Pole, causing the water levels in oceans to rise, flooding low-lying countries.
  • Rapid evaporation of water from the earth’s surface, dry out land, decrease in crop yields
26
Q

Which 2 gases cause acid rain?

A

NO2, SO2

Y4 Chemistry (3 decks)

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