Air Flashcards
What is the volume composition of (clean, dry) air?
O2: 21%
N2: 78%
CO2: 0.03%
Rare gases (mainly Argon):1%
What are some common atmospheric pollutants? (7)
Carbon Monoxide (CO) Methane (CH4) Nitrogen Oxides (NO, NO2) Sulfur Dioxide (SO2) Ozone (O3) Unburnt hydrocarbons
Is CO2 a pollutant?
No, it already occurs naturally in the atmosphere
Where does carbon monoxide (CO) come from?
Carbon monoxide is the product of incomplete combustion of carbon-containing substances (ie. petrol & ethanol)
What are the effects of carbon monoxide?
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.
How is carbon monoxide removed?
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
Where do nitrogen oxides come from?
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
What are the effects of nitrogen (di)oxide and sulfur dioxide?
*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
How does nitrogen dioxide become acid rain?
Nitrogen dioxide dissolves in rainwater and is oxidized by atmospheric oxygen to form nitric acid
How are nitrogen oxides removed?
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)
Where does sulfur dioxide come from?
It is a product of volcanic eruptions and the combustion of fossil fuels (ie. coal)
How does sulfur dioxide form acid rain?
Sulfur dioxide dissolves in rainwater to form sulfurous acid, which is oxidized by atmospheric oxygen to form sulfuric acid
Why is acid rain undesirable?
- Acid rain corrodes buildings made of cement, reactive metals, and limestone
- It also decreases the pH in soil, making it unsuitable to grow crops
How is the effect of acid rain on crops mitigated?
Usage of calcium carbonate to reduce the effects of acid rain on soil pH
CaCO3- CaCO4
How is Sulfur dioxide removed?
Moist calcium carbonate is used in flue gas (waste gas) desulfurization to remove the liberation of SO2.