crude oil. microscopic plants and animals die and fall to the sea bed layers of sand and mud form on...
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Crude Oil
• Microscopic plants and animals die and fall to the sea bed• Layers of sand and mud form on top• Pressure and high temperature cause oil to form
How crude oil was formed
• Oil obtained by drilling
Heated Crude Oil
350o
C
40o
C
Liquid petroleum gas
Naphtha
Petrol (gasoline)
Paraffin
Diesel
Fuel oil
Lubricating oil
Bitumen
Fraction Boiling pt.
< 25oC
25 – 60oC
60 – 180oC
180 – 220oC
220 – 250oC
250 – 300oC
300 – 350oC
> 350oC
Average number of C atoms in chain
3
8
10
12
20
40
80
120
The Fractional Distillation of Crude Oil
Properties of the fractions
The compounds produced by the distillation of crude oil are all hydrocarbons.
Hydrocarbons are compounds which contain the elements hydrogen and carbon.
Naming hydrocarbons
Alkanes
Methane
Ethane Propane
These hydrocarbons are said to be saturated.
(They have single bonds between carbon atoms).
C2H6 C3H8CH4
Fuels
Most alkanes are used as fuels to produce useful forms of energy.
When completely burned alkanes form carbon dioxide and water.
Equations for combustion
CH4
methane
+ O2
oxygen
CO2
carbon dioxide
+ H2O
water
2 2
C3H8 + O2 CO2 + H2O
C2H4 + O2 CO2 + H2O2 2
5 3 4
3
Combustion of hydrocarbonsWhen burned with sufficient oxygen, hydrocarbons
form carbon dioxide and water
Alkenes
Ethene
Alkenes are said to be unsaturated
Test for an unsaturated hydrocarbon (an alkene)Add unsaturated compound
Shake
C2H4
Global dimming
Particulates in soot come from the incomplete combustion of fuel leaving carbon particles. These particles cause Global Dimming by reflecting sunlight away from the Earth.
Global Warming
• main cause: carbon dioxide from burning fossil fuels causing a “greenhouse” effect (also methane).
• Effect on the environment?
• Reducing the Problem?
Acid rain
• Main cause: sulfur compounds in fuels burning to form sulphur dioxide which dissolves in rainwater to produce an acidic solution ( also causes nitrogen oxides from car exhausts.
• Effect on the environment?
• Reducing the problem?
Hydrogen: produced by passing an electric current through water and the process therefore requires lots of energy. Hydrogen is highly flammable and would have to be stored under special conditions.
Only product is water, therefore no pollution.
Hydrogen + Oxygen Water + Energy
Ethanol is made by fermentation of sugar (this process is used to make alcoholic drinks).
It is made from sugar cane which comes from countries such as Brazil. Ethanol burns more cleanly than petrol but produces less energy. It also form carbon dioxide (but it is carbon neutral since the plants absorbed it in the first place.
