Crude oil and fuels

• What is a hydrocarbon?

  A compound containing carbon and hydrogen only
• How is crude oil formed?

  Over millions of years from the remains of ancient biomass
• What are the alkanes?

  Hydrocarbons that only have single bonds
• What are the first four alkanes?

  Methane, ethane, propane, butane
• What is the general formula for the alkanes?

  CnH2n+2
• How does boiling point depend on the chain length of alkanes?

  The longer the chain, the higher the boiling point
• How does viscosity depend on chain length?

  The longer the chain, the higher the viscosity
• How does flammability depend on chain length?

  The longer the chain, the lower the flammability
• How can the different alkanes in crude oil be separated?

  Through fractional distillation
• What is a fraction in the context of hydrocarbons?

  A group of hydrocarbons with similar chain lengths
• Name five useful fuels produced from fractional distillation.

  Petrol, diesel oil, kerosene, heavy fuel oil, and liquefied petroleum gases
• Name four useful materials produced from crude oil fractions.

  Solvents, lubricants, polymers, detergents
• What is cracking in the context of hydrocarbons?

  Breaking down a hydrocarbon with a long chain into smaller molecules
• Name two methods to carry out cracking.

  Steam cracking and catalytic cracking
• What are the products of cracking?

  Short chain alkanes and alkenes
• What are alkenes?

  Hydrocarbons with a double bond
• What are alkenes used for?

  Formation of polymers
• How does the reactivity of alkenes compare to alkanes?

  Alkenes are much more reactive
• How can you test for alkenes?

  Alkenes turn orange bromine water colourless