3. How crude oil was formed
• 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
• Oil obtained by drilling
4. Oil is a fossil fuel
Other fossils fuels are:
Coal and Gas
5. Non-renewable Renewable
Biofuels – ethanol and
biodiesel made from plants
6. Crude oil is a
mixture of a very
large number of
compounds.
These compounds
can be separated
by distillation.
7. The Fractional Distillation of Crude Oil
Average number of
C atoms in chain
Fraction Boiling pt.
Liquid petroleum
< 25oC 3
gas
40o
Petrol (gasoline) 25 – 60oC 8
C
Very hot crude oil is pumped into
Naphtha 60 – 180oC 10
the fractionating column where the
hydrocarbons separate180 – by their boiling points,
out 220oC 12
Paraffin
rising through the column until they get cold
enough Diesel
to condense. The compounds that
220 – 250oC 20
condense at a particular temperature are called a
FRACTION.
Fuel oil 250 – 300oC 40
Lubricating oil 300 – 350oC 80
350oC
Bitumen > 350oC 120
Heated
Crude
Oil
9. Most of the compounds in crude oil consist of
molecules made up of hydrogen and carbon atoms
only (hydrocarbons). Most of these are saturated
hydrocarbons called alkanes.
CH4 C2H6
C3H8
Write the chemical In general:
formula for these
alkanes
CnH2n+2
C4H10
11. Fuels
Most alkanes are used as fuels to produce useful forms of
energy.
When completely burned alkanes form carbon dioxide
and water.
12. Equations for combustion
CH4 + 2 O2 CO2 + 2 H2O
methane oxygen carbon water
dioxide
C3H8 + 5 O2 3 CO2 + 4 H2O
C2H4 + 3 O2 2 CO2 + 2H2O
13. Most fuels, including coal, contain carbon and/or
hydrogen and may also contain some sulfur.
The gases released into the atmosphere when a fuel burns
may include:
•carbon dioxide GLOBAL WARMING
•water (vapour)
•carbon monoxide
•sulfur dioxide and ACID RAIN
•oxides of nitrogen.
Solid particles (particulates - sometimes called soot) may
also be released. GLOBAL DIMMING
