Crude oil is a mixture of hydrocarbons, which are long chains of hydrogen and carbon atoms.
alkanes are saturated hydrocarbons, they contain C-C and C-H bonds only, they are apart of the same homologous series as they have the same general formula and properties
Alkanes follow the general formula CnH2n+2
Properties of long chain hydrocarbons -
high viscosity
properties of long chain hydrocarbons -
high viscosity
low volatility
low flammability
high boiling point
properties of short chain hydrocarbons -
low viscosity
high volatility
high flammability
low boiling point
HydroCarbons can be broken down (cracked) to produce smaller, more useful molecules
Catalytic cracking - cheaper
Zeolite catalyst (contains Aluminium Oxide)
Temperature of 500 degrees Centigrade
Steam cracking
no catalyst
higher temperature (750 degrees Centigrade)
when cracking occurs a long chain alkane is thermally decomposed into a mixture of shorter alkanes and alkenes
alkenes are unsaturated as they contain a C=C bond
Polymers (plastics) - long molecules of repeating monomers (small molecules)
Fractional distillation
heat crude oil to a vapour
vapours enter column at the bottom and separate by boiling point
the column is coolest at the top, and hottest at the bottom
fractions (hydrocarbons) condense at different temperatures
shorter fractions condense towards the top due to their lower boiling point
Alkene + Bromine turns colourless, Alkenes react with Bromine because of their double Carbon bond