DF - inorganic chemistry and the periodic table Flashcards
atmospheric pollutants
CO, CO2, NOx, SOx
origin of atmospheric pollutants
particulates, unburnt hydrocarbons
greenhouse effect
The earth naturally radiates infra-red radiation out into space. But greenhouse gases in the atmosphere absorb some of this radiation. This is called the greenhouse effect and it keeps the earth warm
Origin of Carbon Dioxide, CO2
Burning carbon-based fuels (transport, power stations) is one factor that is causing an increase in the amount of CO2 in the atmosphere.
Implication of Carbon Dioxide, CO2
The build-up of CO2 and other greenhouse gases is causing the enhanced greenhouse effect or global warming
this is causing the earth to warm up slowly, which is a huge problem
controlling global warming isn’t easy and needs a sustained effort from countries all around the world
Origin of Carbon Monoxide, CO
incomplete combustion, so get carbon monoxide instead of carbon dioxide
Alkanes
CH4 (g) + 1/2O2 (g) –> CO (g) + 2H2O
Cycloalkanes
C4H8 (g) + 4O2 (g) –> 4CO (g) + 4H2O (g)
Alkenes
C4H8 (g) + 4O2 (g) –> 4CO (g) + 4H2O (g)
Alcohols
CH3OH (l) + O2 (g) –> CO (g) + 2H2O (g)
Implications of Carbon Monoxide, CO
CO is poisonous
- the molecules are chemically similar to O2 molecules
- this means CO can bind to the same sites on haemoglobin molecules in RBC as O2 molecules
- so less O2 can be carried around the body, so if you breath too much CO in can suffer internal suffocation
Origin of unburnt hydrocarbons
engines dont burn all the fuel molecules, some of these come out as unburt hydrocarbons
origin of Oxides of Nitrogen, NOx
produced when the high pressure and temp. in a car engine cause the nitrogen and oxygen in the air to react together.
Implications of NOx
can cause acid rain
when NOx escapes into the atmosphere its dissolves in the moisture and is converted to nitric acid
- destroys vegetation
- corrodes buildings and statues
- kills fish in lakes
Implication of unburnt hydrocarbons and nitrogen oxides, NOx
the hydrocarbons the nitrogen oxides react, in sunlight, to form ground level ozone (O3), this is a component of photochemical smog
- irritate eyes
- aggravate respiratory problems
- cause lung damage
Origin of Sulfur Dioxide, SO2
Burning fossil fuels that contain sulfur produces sulfur dioxide
Implications of sulfur dioxide, SO2
can cause acid rain
when SO2 escapes into the atmosphere its dissolves in the moisture and converted to sulfuric acid
- destroys vegetation
- corrodes buildings and statues
- kills fish in lakes
Origin of Particulates
Particulates are tiny particles of liquid suspended in the air.
Solid particulates, such as carbon, are produced in the burning of fossil fuels in vehicles and power stations
Implications of particulates
settle in people’s lungs and cause:
- decreased lung function
- irritation of airways
also contribute to cardiovascular problems which can lead to:
- heart attacks
- strokes
what are the biggest sources of air pollutants
- transport
- industry
- power generation
Methods of reducing sulfur dioxides, SO2
sulfur dioxide is removed from power station flue (emissions from industrial exhausts and chimneys) gases using calcium oxide
Method of reducing particulates
particulates are removed from:
- power station flue gases using wet scrubbers which capture them in water droplets
- some car exhausts using filters
Use of catalytic converters
reduce carbon monoxide, unburnt hydrocarbons, sulfur dioxide and nitrogen oxide emissions from vehicles.
Method of reducing Carbon Monoxide, CO
oxygenates are added to petrol to help the fuel fully combust
What could be done quickly to reduce the problem of pollution
- governments could change laws
eg. in UK sulfur and nitrogen oxide emissions from power stations have been reduced as laws about emissions have been tightened - new vehicles are not allowed to pollute above a certain level and the yearly MOT inspection included an emissions test. Catalytic converters have been compulsory on new cars in the UK since 1992
- governments can tax pollution more highly
eg. raise taxes on fuel, or on highly polluting engines - people can reduce the amount of pollution they produce by changing their behaviour
eg. fewer car journeys or car share
What could be done in the long term to reduce pollutants
develop new fuels that cause less polution
