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Atmospheric Pollutants (Catalytic converters (Catalyst's and reaction.…
Atmospheric Pollutants
what they do.
Carbon monoxide is a poisonous gas. Oxides of nitrogen (NOx) react with other pollutants in sunlight to form a photochemical smog, which causes breathing difficulties.
NOx and sulphur dioxide also form acid rain. This has several effects on the environment, including:
killing plants and aquatic life
eroding stonework
corroding metals
Equations
S + O2 ➝ SO2
C7 H16 + 8O2 ➝ CO2 + 6CO + 8H2 O Incomplete combustion
C7 H16 + 11O2 ➝ 7CO2 + 8H2 O Complete combustion
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Catalytic converters
Car exhaust systems have catalytic converters. These convert carbon monoxide into carbon dioxide:
carbon monoxide + nitrogen oxide → nitrogen + carbon dioxide
2CO + 2NO → N2 + 2CO2
A catalyst is a substance that can increase the rate of a reaction. The catalyst itself remains unchanged at the end of the reaction it catalyses. Only a very small amount of catalyst is needed to increase the rate of reaction between large amounts of reactants.
Different catalysts catalyse different reactions. The table summarises some common catalysts used in industry and the reactions they catalyse.
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Catalytic converters
Modern cars have a catalytic converter to help reduce the production of toxic gases. Catalytic converters use a platinum and rhodium catalyst with a high surface area. This increases the rate of reaction of carbon monoxide and unburnt fuel from exhaust gases with oxygen from the air. The product from this is carbon dioxide and water, which is less harmful to the environment. The catalysts are designed to work best at the high temperatures found in the engine.
Human activities produce a number of gases that are released into the atmosphere. Most of these pollutant gases are produced by the burning of fuels.
The burning of fuels releases a large amount of carbon dioxide into the atmosphere. This is thought to cause global warming.
Other pollutant gases which are released into the air when fuels are burned include carbon monoxide, nitrogen oxides and sulfur dioxide.
The incomplete combustion of fuels also releases small particles of solids, such as carbon, into the air. This makes buildings dirty and affects the lungs.
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