PETROLEUM
produce petrol, jet fuel, kerosene, and other hydrocarbons. For example, 2,2,4-
trimethylpentane (isooctane), widely used in petrol, has a chemical formula of C8H18
and it reacts with oxygen exothermically:
2 C8H18(l) + 25 O2(g) → 16 CO2(g) + 18 H2O(g) (ΔH = −10.86 MJ/mol of octane)
The amount of various molecules in an oil sample can be determined in laboratory. The
molecules are typically extracted in a solvent, then separated in a gas chromatograph,
and finally determined with a suitable detector, such as a flame ionization detector or a
mass spectrometer. Due to the large number of co-eluted hydrocarbons within oil, many
cannot be resolved by traditional gas chromatography and typically appear as a hump in
the chromatogram. This unresolved complex mixture (UCM) of hydrocarbons is
particularly apparent when analysing weathered oils and extracts from tissues of
organisms exposed to oil.
annaabi.ee 
