Organic chemistry

• Crude oil is formed from the remains from ancient biomass - organisms that lived millions of years ago
• Raw crude oil is made of mostly hydrocarbons of various sizes
• Why are hydrocarbons used as fuels?

  When they react with oxygen they release alot of energy (combustion)
• What properties make a hydrocarbon useful as fuel?

  Flammability - How easily it burns

  Boiling point - The temp at which it boils

  Viscosity - How thick it is
• Long chain properties

  Flammability - Low

  Boiling point - High

  Viscosity - High
• Short chain properties

  Flammability - High

  Boiling point - Low

  Viscosity - Low
• Alkanes are one family of hydrocarbons
• What type of bonds do alkanes have?

  Single
• First 4 alkanes

  Methane, Ethane, Propane, Butane
• Alkenes are one family of hydrocarbons
• More reactive: Alkenes
• How do you tell the diff between alkanes and alkenes

  When alkenes are mixed with bromine water it turns from orange to colourless
• What does fractional distillation do for crude oil?

  Separate the different hydrocarbons in crude oil based on their boiling points
• Fractional distillation takes pace in a fractionating column, which is hot at the bottom and cooler at the top
• Fractional distillation process

  1. Crude oil is vaporised
  2. Hydrocarbon gasses enter the column
  3. They rise up
  4. As they rise, they cool down
  5. When they reach their boiling points they condense
  6. The hydrocarbon fraction is collected
• Fuels from fractional distillation

  1. Petrol
  2. Diesel oil
  3. Kerosene
  4. Heavy fuel oil
  5. Liquefied petroleum gases
• Useful materials from fractional distillation

  1. Solvents
  2. Lubricants
  3. Polymers
  4. Detergents
• Longer molecules are less useful than shorter ones
• Higher demand for short chain hydrocarbons
• Cracking

  Process used to break up long chain hydrocarbons into short chained alkanes and alkenes
• 2 methods of cracking

  1. Catalytic cracking
  2. Steam cracking
• Catalytic cracking

  Vaporise the hydrocarbons, then pass them over a hot catalyst
• Steam cracking

  Mix the hydrocarbons with steam at a very high temperature