7.1 Carbon compounds as fuels and feedstock

• What type of resource is crude oil?


  Finite resource
• What is crude oil primarily composed of?


  Remains of ancient biomass, mainly plankton
• Where is crude oil found?


  In rocks
• What is a mixture in the context of crude oil?


  Two or more elements not chemically combined
• How are the chemical properties of substances in crude oil affected?


  They remain unchanged
• What physical method can separate substances in crude oil?


  Distillation
• What are hydrocarbons primarily made of?


  Hydrogen and carbon
• What are most hydrocarbons in crude oil classified as?


  Saturated hydrocarbons, mainly alkanes
• What are the first four alkanes?


  • Methane
  • Ethane
  • Propane
  • Butane
• How does fractional distillation work?


  Oil is heated, evaporates, and condenses
• What does the fractionating column do?


  Separates hydrocarbons into fractions
• How is crude oil introduced into the fractionating column?


  Piped in at the bottom
• What happens to vaporised oil in the fractionating column?


  It rises and condenses at different levels
• What can the fractions from crude oil be processed into?


  Fuels and feedstock for petrochemicals
• What fuels are produced from crude oil?


  Petrol, diesel, kerosene, heavy fuel oil
• What materials does the petrochemical industry produce?


  Solvents, lubricants, polymers, detergents
• Why do carbon compounds vary widely?


  Carbon can form families of similar compounds
• How do the properties of hydrocarbons depend on their molecular size?


  Properties influence their use as fuels
• What happens to the viscosity of hydrocarbons as their molecules get shorter?


  They become less viscous
• How does the boiling point of hydrocarbons change with molecular size?


  Shorter molecules have lower boiling points
• What is the relationship between molecular size and flammability of hydrocarbons?


  Shorter molecules are more flammable
• Why are hydrocarbons burned as fuel?


  They produce energy when oxidised
• What is the general reaction for burning hydrocarbons?


  Hydrocarbon -> carbon dioxide + water
• What is cracking in the context of hydrocarbons?


  Breaking down hydrocarbons into smaller molecules
• What are the two processes of cracking hydrocarbons?


  Catalytic cracking and steam cracking
• What are the first two alkenes?


  Ethene and propene
• How do alkenes react with bromine water?


  They turn it from orange to colourless
• Why are alkenes more reactive than alkanes?


  Due to the presence of a double bond
• What are alkenes used for in industry?


  Producing other chemicals like polymers
• Why are products from cracking useful as fuels?


  They have shorter chains, making them more flammable
• What must be ensured in the equations for cracking?


  Same number of carbons and hydrogens on each side
• What is the typical outcome of a cracking reaction?


  Going from a bigger molecule to smaller molecules