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
6. Crude oil is a
mixture of a very
large number of
compounds.
These compounds
can be separated
by distillation.
7. Heated
Crude
Oil
40o
C
350oC
Fraction Boiling pt.
Liquid petroleum
gas
Petrol (gasoline)
Naphtha
Paraffin
Diesel
Fuel oil
Lubricating oil
Bitumen
< 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
Very hot crude oil is pumped into
the fractionating column where the
hydrocarbons separate out by their boiling points,
rising through the column until they get cold
enough to condense. The compounds that
condense at a particular temperature are called a
FRACTION.
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.
Write the chemical
formula for these
alkanes
In general:
CH4 C2H6
C3H8
C4H10
CnH2n+2
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
methane
+ O2
2 2
oxygen
CO2
carbon
dioxide
+ H2O
water
CH+ 5 O3 CO+ 4
HO
38 2 2 2CH+ 3
O2CO+ 2 HO
24 2 2 2
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
