crude oil

• crude oil is made over a ... period of time


  long
• crude oil is a...

  fossil fuel
• fossil fuel


  a natural fuel such as coal or gas, formed in the geological past from the remains of living organisms, containing hydrogen and carbon atoms. they are non-renewable
• non-renewable fuels


  limited in supply as there is a finite amount of them on earth, or because they take a long time to form
• crude oil is a mixture of...

  lots of different hydrocarbons, most of which are alkanes
• the different compounds in crude oil are separated by...

  fractional distillation
• fractional distillation


  separation of a liquid mixture into fractions differing in boiling point (and hence chemical composition) by means of distillation, typically using a fractionating column
• fractioning column


  the apparatus used to distil hydrocarbons
• in the fractioning column...

  the oil is heated until most of it is turned into gas then condensed
• what is the temperature gradient in the fractioning column?

  in the fractioning column it is hotter at the bottom and cooler at the top
• where do longer hydrocarbons condense in the fractioning column?

  at the bottom of the column, where it's hotter
• why do longer hydrocarbons condense/drain out at the bottom of the fractioning column?

  because they have higher boiling points, they condense back into liquids and drain out from the column earlier on at the bottom
• where do shorter hydrocarbons condense/drain out in the fractioning column?


  at the top of the column, where it's cooler
• why do shorter hydrocarbons condense/drain out at the top of the fractioning column?

  because they have lower boiling points, they condense back into liquids and drain out from the column later on at the top
• each fraction of crude oil coming out of the fractioning column contains...

  a mixture of hydrocarbons that all contain a similar number of carbon atoms, so they have similar boiling points
• crude oil uses


  - oil provides the fuel for most modern transport

  - the petrochemical industry uses some of the hydrocarbons from crude oil as a feedstock to make new compounds for use in things like polymers, solvents, lubricants, and detergents

  - all products from crude oil are organic compounds (compounds w/ carbon atoms)
• cracking


  the breaking down of long-chained saturated hydrocarbons to form a mixture of shorter-chained alkanes and alkenes.
• are short chained or long chained hydrocarbons more in demand?


  short chained
• why are short chained hydrocarbons in greater demand?

  because they are flammable, making them good fuels
• why are long chained hydrocarbons in lower demand?

  because they form viscous, inflammable liquids (like tar) which is not very useful
• how are longer alkane molecules turned into shorter, more useful ones?

  with cracking
• a long alkane molecule goes through cracking to form...

  a shorter alkane molecule and an alkene
• cracking is a ... reaction

  thermal decomposition
• thermal decomposition


  the breaking up of a chemical substance with heat into at least two chemical substances.
• catalytic cracking


  where a long chain hydrocarbon is vapourised then passed over a hot catalyst, causing it to split apart
• steam cracking


  where a long chain hydrocarbon is vapourised then mixed in team and heated to a very high temperature