crude oil and fuels

• What is crude oil formed from?

  Remains of ancient biomass
• Why is crude oil important to society?

  It is crucial for our economy and energy
• What is raw crude oil described as?

  A thick black liquid
• What are hydrocarbons made of?

  Carbon and hydrogen only
• What happens when hydrocarbons react with oxygen?

  They release a lot of energy
• What is the reaction called when hydrocarbons react with oxygen?

  Combustion
• What are the products of complete combustion?

  Carbon dioxide and water
• What properties determine if a hydrocarbon is used as fuel?

  • Flammability: how easily it burns
  • Boiling point: temperature at which it boils
  • Viscosity: how thick it is
• How does the length of a hydrocarbon molecule affect its properties?

  It influences flammability, boiling point, and viscosity
• What are the properties of long-chain hydrocarbons?

  • Low flammability
  • High boiling point
  • Very thick
• What are the properties of short-chain hydrocarbons?

  • High flammability
  • Low boiling point
  • Very runny
• What is the process used to separate hydrocarbons in crude oil?

  Fractional distillation
• How are hydrocarbons separated in fractional distillation?

  Based on their boiling points
• What is the temperature gradient in a fractioning column?

  Hot at the bottom, cooler at the top
• What are the steps in the fractional distillation process?

  1. Crude oil is vaporized
  2. Hydrocarbon gases enter the column
  3. Gases rise up the column
  4. Gases cool down
  5. Hydrocarbons condense at boiling points
  6. Hydrocarbon fraction is collected
• What are some products obtained from fractional distillation?

  • Fuels: petrol, diesel, kerosene
  • Feedstock: raw materials for other processes
  • Useful materials: solvents, lubricants, polymers, detergents
• Why are longer hydrocarbons less useful than shorter ones?

  Shorter hydrocarbons are in higher demand
• What is the purpose of cracking in hydrocarbons?

  To break up longer hydrocarbons into shorter ones
• What are the two methods of cracking hydrocarbons?

  • Catalytic cracking: vaporize and pass over a hot catalyst
  • Steam cracking: mix with steam at high temperature
• What distinguishes alkenes from alkanes?

  Alkenes contain double bonds
• How do alkenes react with bromine water?

  They turn bromine water from brown to colorless
• What is the molecular formula for alkanes?

  $C_nH_{2n+2}$
• What are the first four alkanes and their structures?

  Methane, ethane, propane, butane
• How can you determine the molecular formula of an alkane?

  By using the formula $C_nH_{2n+2}$