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Chemistry Topic 8: Fuels & Earth and Atmospheric science (Climate…
Chemistry Topic 8: Fuels & Earth and Atmospheric science
Complete combustion
Hydrocarbons burn in an excess of air to produce carbon and water only.
Hydrocarbon + Oxygen → Carbon dioxide + water
Oxidation reaction
Fractional distillation of crude oil
Crude oil is a
finite
resource meaning that not enough of a supply to meet the world demand or it is running out
Crude oil is a
mixture of hydrocarbons
Names and uses of fractions
Kerosene
Used as fuel for aircraft's
Petrol
Used to fuel cars
Gases
(
Lowest boiling point and viscosity, smallest amount of carbon atoms
)
Used for domestic heating and cooking
Diesel oil
Used to fuel some cars and trains
Fuel oil
Used to fuel lard ships and power stations
Bitumen
(
Highest boiling point and viscosity, largest amount of carbon atoms
)
Used for surfacing roads and roofs
Changing atmosphere
Early Atmosphere
Consisted of mainly carbon dioxide and water vapour
Carbon dioxide dissolved in the oceans
Water vapour condensed to form oceans
No life
Today's atmosphere
Mainly nitrogen and oxygen
Climate change
Increased amounts of greenhouses gasses such as carbon dioxide contribute to global warming
Fossil fuels emit greenhouse gasses when they are:
Burnt in power stations to produce electricity
Burnt to heat our homes
Burnt in car engines
Methane is another major greenhouse gas that contributes to global warming
Reducing greenhouse gas emission
Finding and using renewable energy sources
Capturing carbon dioxide emitted from power stations
Capping landfill sites and using the methane to generate electricity
Human activities such as these produce methane
Finding and processing oil and natural gas
Putting rubbish in landfill sites
Growing rice in paddy fields
Removing Carbon Dioxide
Planting lots of trees to take in carbon dioxide as they grow
Capturing it from the air and burying it underground
Cracking
Oil companies use this to match with supply and demand
Chemical reaction where a large alkane molecule is split into two or more smaller alkanes and alkanes
Involves breaking strong covalent bonds
High temperatures and a catalyst is needed
The smaller hydrocarbons formed are more useful
Incomplete combustion
Occurs when there is limited oxygen, water is still produced but soot(carbon) and carbon monoxide are formed as well as carbon dioxide
Hydrocarbon + Oxygen → Carbon + Carbon monoxide + Carbon Dioxide + Water
Carbon Monoxide is a colourless toxic gas