2.5 - Crude Oil

• Crude oil is a complex mixture of hydrocarbons formed by decomposition of marine organisms over millions of years.


  What is crude oil?
• A substance that contains two or more elements chemically bonded together


  What is a compound?
• Hydrocarbons


  What are the compounds in crude oil called?
• A hydrocarbon is a molecule that is made up from carbon and hydrogen atoms only.


  What is a hydrocarbon?
• By fractional distillation


  How are the crude oil in hydrocarbons in crude oil separated?
• methane, ethane, propane, butane, pentane

  Name the first 5 alkanes?
• As chain length increases, boiling point increases


  What happens to the boiling point of hydrocarbons as the chain length increases
• Why is crude oil useless as it comes out of the ground?
• small molecules, colourless/ pale yellow, thin, burns quickly and easily with not much smoke.


  Fraction: low boiling points
• medium molecules, dark yellow, thick, burns less easily with a smokey flame.

  Fraction: medium boiling points
• large molecules, orange/pale brown, thicker, lots of smoke, very difficult to light.

  Fraction: high boiling points
• petroleum gases, petrol, naphtha, kerosine, diesel

  low temperature fractions
• lubricating oil, heavy fuel oil, bitumen

  high temperature fractions
• Alkanes and alkenes


  What are the two main groups of hydrocarbons?
• Alkanes.


  What kind are the hydrocarbons in Crude oil?
• How easily a liquid flows

  Viscosity
• How easily something burns

  Flammability
• Ease at which a liquid turns to a gas

  Volatility
• Hydrocarbon + O2 = CO2 + H2O


  Complete combustion
• Hydrocarbon + O2 = CO + H2O


  Incomplete combustion (gas)
• Hydrocarbon + O2 = C + H2O


  Incomplete combustion (solid)
• Exothermically- gives out heat energy, feels hot


  What way do fuels burn?
• Hydrocarbons, saturated compounds, act as fuels, burn cleanly, only have c-c single bonds.

  Alkanes
• Hydrocarbons, unsaturated compounds, used as plastics, contain c=c double bonds.

  Alkenes
• Meth


  Number of carbon atoms: 1
• Eth


  Number of carbon atoms: 2
• Prop


  Number of carbon atoms: 3
• But


  Number of carbon atoms: 4
• Pent


  Number of carbon atoms: 5
• Hex


  Number of carbon atoms: 6
• CnH2n+2


  General formula for alkanes
• CnH2n


  General formula for alkenes
• An atom or a group of atoms which are responsible for the chemical properties of the compound

  Functional group
• Compounds having the same general formula, the same functional group, the same chemical properties but show a trend in their physical properties. differ by CH2


  Homologous series
• double bonds


  unsaturated
• single bonds


  saturated
• Alkanes are generally unreactive. However, when they are exposed to U.V. light they will react with chlorine or bromine in a substitution reaction.


  alkane's reactivity
• Cracking is a process where long useless hydrocarbon chains ar broken down to smaller more useful ones using a catalyst + high temperatures.


  Cracking
• Same molecular formula, different structures.

  Structural isomerism
• Alkane + Br2 - substitution

  Alkene + Br2 - addition


  Reaction with bromine water