crude oil and hydrocarbons

• What are hydrocarbons composed of?

  Hydrogen and carbon atoms only
• What is crude oil?

  A complex mixture of hydrocarbons
• How are carbon atoms arranged in crude oil molecules?

  In chains and rings
• What do the ball and stick models represent?

  Carbon atoms as black and hydrogen as white
• Why is crude oil considered a finite resource?

  It forms extremely slowly over millions of years
• What are the main uses of crude oil?

  • Fuels
  • Feedstock for the petrochemical industry
• What is a feedstock?

  A raw material for industrial reactions
• What is an example of a petrochemical produced from crude oil?

  Ethene
• What is fractional distillation used for?

  To separate crude oil into useful mixtures
• Why can fractional distillation separate hydrocarbons?

  Different hydrocarbons have different boiling points
• Describe the process of fractional distillation of crude oil.

  1. Heated crude oil enters a fractionating column
  2. Vapours rise through the column
  3. Vapours condense at cooler temperatures
  4. Liquids are collected at different heights
• What happens to hydrocarbons with low boiling points during distillation?

  They leave the column as gases
• What is bitumen used for?

  Roads and roofs
• What are fossil fuels and give examples?

  • Non-renewable fuels from crude oil or natural gas
  • Examples: petrol, kerosene, diesel oil, methane
• Why are fossil fuels considered non-renewable?

  They are used faster than they are formed
• What mnemonic helps remember the names of crude oil fractions?

  'Good Penguins Keep Diving For Bass'
• What are the properties of crude oil fractions?

  • Mixture of hydrocarbons
  • Mostly alkanes
  • Similar boiling points and ease of ignition
  • Viscosity varies
• What is a homologous series?

  A series of compounds with similar properties
• What is the general formula for alkanes?

  $C_nH_{2n+2}$
• How do boiling points change with increasing carbon atoms in alkanes?

  Boiling points increase with more carbon atoms
• What are the two types of combustion of hydrocarbon fuels?

  • Complete combustion
  • Incomplete combustion
• What is produced during complete combustion of hydrocarbons?

  Carbon dioxide and water
• What is the equation for complete combustion of propane?

  $C_3H_8 +$$5O_2 \rightarrow 3CO_2 +$$4H_2O$
• What happens during incomplete combustion?

  Carbon monoxide and carbon are produced
• What is soot?

  Fine black particles from incomplete combustion
• Why is carbon monoxide dangerous?

  It reduces blood's oxygen-carrying capacity
• What are the pollutants produced by hydrocarbon combustion?

  • Carbon and soot
  • Sulfur dioxide
  • Oxides of nitrogen
• What does sulfur dioxide form when dissolved in water?

  Sulfurous acid
• What is acid rain?

  Rain that contains sulfuric and sulfurous acids
• How does acid rain affect the environment?

  Damages buildings, plants, and aquatic life
• What is produced when nitrogen and oxygen react at high temperatures?

  Oxides of nitrogen
• What is cracking in hydrocarbons?

  A reaction breaking larger molecules into smaller ones
• What are the products of cracking hexane?

  Butane and ethene
• Why is cracking important?

  It matches supply with demand for hydrocarbons
• Compare alkanes and alkenes.

  • Alkanes: saturated, C-C single bonds
  • Alkenes: unsaturated, at least one C=C double bond
• What is the main advantage of hydrogen as a fuel?

  Water is the only product of combustion
• What is the main disadvantage of hydrogen as a fuel?

  Fewer filling stations than petrol stations
• How is hydrogen produced from methane?

  By reacting with steam
• What is the state of hydrogen at room temperature?

  Gas
• Compare hydrogen and petrol as fuels.

  • Hydrogen: gas, very flammable, high energy per kg
  • Petrol: liquid, very flammable, lower energy per kg