C7 Organic Chemistry

• Crude oil is a finite resource, meaning that one day we will run out
• Crude oil comes from bounding rocks and is the remains of ancient biomass consisting mainly of plankton and zooplankton that died approximately 340 million years ago
• Formation of crude oil

  Under anaerobic conditions, ancient sea creatures covered in sand and silt turned into crude oil over time due to heat and pressure
• Compounds in crude oil

  • Mostly hydrocarbons
• Hydrocarbon

  A molecule made up of hydrogen and carbon atoms only
• Most hydrocarbons in crude oil are alkanes
• General formula for alkanes

  CnH2n+2
• First four members of the alkane family

  • Methane, Ethane, Propane, Butane
• Display formula for alkanes

  Show the covalent bonds present
• Fractional distillation

  Separating hydrocarbons in crude oil into fractions by heating the mixture to a gas and then condensing it in a column with varying temperatures
• Products from crude oil fractions

  • Petrol, Kerosene, Fuel oil, Liquefied petroleum gases
• Many useful materials like solvents, lubricants, polymers, and detergents can be made from crude oil fractions
• Carbon atoms

  Can form families of similar compounds
• Products that can be made from hydrocarbons

  • Solvents
  • Lubricants
  • Polymers
  • Detergents
• A vast array of natural and synthetic carbon compounds occur due to the ability of carbon atoms to form families of similar compounds
• Alkanes are a type of hydrocarbon
• Properties of hydrocarbons

  • Depend on the size of the molecule
  • Boiling point increases with carbon chain length
  • Viscosity increases with carbon chain length
  • Flammability decreases as carbon chain length decreases
• Fractions in order from the top of the column in a refinery

  • Refinery gases
  • Gasoline (Petrol)
  • Kerosene (Paraffin)
  • Diesel
  • Lubrication oil
  • Fuel oil
  • Bitumen (Tar)
• Refinery gases have a low boiling point as they were already gases at room temperature
• Tar has an incredibly high boiling point and viscosity
• Viscosity

  A measure of how runny something is or how much they stick to each other
• Flammability trend in hydrocarbons

  Becomes easier to light or more flammable as carbon chain length decreases
• Combustion of hydrocarbons produces energy, carbon dioxide, and water
• Incomplete combustion of hydrocarbons results in the production of carbon monoxide
• Testing for products of combustion can be done using anhydrous copper sulphate or copper chloride paper for water, and lime water for carbon dioxide
• Cracking in alkenes

  Long-chain alkanes are broken down into shorter alkanes and alkenes
• Cracking can be done by catalytic cracking or steam cracking
• Alkenes are more reactive than alkanes and react with bromine water
• Bromine water is used as a test for alkenes
• Decolorization of bromine water indicates the presence of alkenes
• There was a high demand for fuels with small molecules such as petrol and diesel
• The color that the bromine which made the solution orange is now gone, we would say that it decolorizes the bromine water
• Products of cracking that are useful as fuels

  • Gases used for heating and cooking
  • Petrol use for cars
  • Diesel use for cars and lorries
• Demand for gases used for heating and cooking, petrol, and diesel

  Far exceeds the supply available
• Demand for kerosene and fuel oil

  Greater supply and demand can be met
• Meeting the demand for shorter alkanes

  By breaking the longer chain alkanes using cracking
• Our modern life depends on the uses of hydrocarbons
• Another use of alkenes produced from cracking

  To produce polymers
• Polymers

  • Polythene
• A test that shows that molecules of propane contain a carbon to carbon double bond is using bromine water, which turns from orange to colorless or decolorizes