Earth resources

• Element

  One or a pair of the same type of atom (same proton number)
• Compound

  Two or more different elements chemically bonded
• Mixture

  Different elements, compounds not chemically bonded
• Crude oil

  • A finite resource and a fossil fuel
• Products from crude oil

  • Fuels: petrol, diesel, kerosene, liquified petroleum gas
  • Feedstock for the petrochemical industry
• Formation of crude oil

  1. Small creatures (mainly plankton) died and fell onto the seabed

  2. Covered in mud and prevented from decaying

  3. Further layers of mud and sand squashed the remains and buried them deeper and deeper

  4. Layers put pressure on the dead creatures exposing them to temperatures: 90°C-120°C

  5. Millions of years of pressure and heat turned them into crude oil and natural gas
• Crude oil

  A complex mixture of hydrocarbons, most of which are alkenes
• Alkenes


  • Part of a homologous series
  • Have same general formula
  • Differ by CH2
  • Show gradual variation in physical properties like boiling points
  • Have similar chemical properties
• First 12 hydrocarbons

  • Methane
  • Ethane
  • Propane
  • Butane
  • Pentane
  • Hexane
  • Heptane
  • Octane
  • Nonane
  • Decane
  • Undecane
  • Dodecane
• Fractional distillation of crude oil

  1. Crude oil is heated until it is gas

  2. Gas is pumped into a fractionating tower where the bottom is hot and the top is cold

  3. The fractions condense into liquid and are collected

  4. Larger hydrocarbons with higher boiling points condense at the bottom, smaller ones at the top
• Saturated hydrocarbons

  Hydrocarbons with carbon-carbon single bonds
• Unsaturated hydrocarbons

  Hydrocarbons with carbon-carbon double bonds (alkenes)
• Steam cracking


  1. Long chain hydrocarbon is turned into gas

  2. Mixed with steam

  3. Heated to over 850°C under pressure to split into shorter alkanes and alkenes

  4. Alkenes are separated by fractional distillation and used to make polymers
• Catalytic cracking


  1. Long chain hydrocarbon is turned into gas

  2. Passed over a hot, powdered aluminium silicate catalyst at around 180°C

  3. Splits into products as it passes over the catalyst surface
• Short hydrocarbons

  Have high flammability making them useful fuels
• Polymers from alkenes


  • Poly(ethene)
  • Poly(propene)
  • PTFE
  • PVC
• Bromine water test

  Alkanes show no change, alkenes turn the bromine water colourless
• The atmosphere has not changed in 200 million years
• Formation of the atmosphere

  1. Intense volcanic activity released carbon dioxide, sulphur dioxide and water

  2. As the Earth cooled, the water condensed to form the oceans

  3. Nitrogen built up as it is unreactive
• Composition of the early atmosphere

  • 95% carbon dioxide
  • 4% water
  • Traces of nitrogen, ammonia, methane
• Increase in oxygen in the atmosphere

  1. Development of algae 2.7 million years ago produced oxygen through photosynthesis

  2. Buildup of oxygen enabled animals to evolve
• Decrease in carbon dioxide levels

  1. Formation of sedimentary rocks as carbon dioxide dissolved in water to form carbonate compounds

  2. Uptake of carbon dioxide by living organisms, some of which became fossil fuels
• Greenhouse effect

  Greenhouse gases (carbon dioxide, water, methane) absorb heat radiated from the Earth and release it in all directions, keeping the Earth warm
• Human activities

  Increase the amount of greenhouse gases (e.g. cattle farming, rice farming, burning fossil fuels, deforestation)
• Evidence of increased CO2 and effects of global warming
• Carbon footprint


  The total amount of carbon dioxide (and other greenhouse gases) emitted over the full cycle of a product, service or event
• Ways to reduce carbon footprint

  • Fit photovoltaic cells
  • Insulate homes
  • Use public transport
  • Reduce, reuse, recycle
• Models

  Simplified, biased, inaccurate and based on only some of the evidence
• Peer-reviewed process

  A scientific report is reviewed and checked for accuracy by other scientific experts
• Sun


  • Gives off solar radiation which is short wavelength
  • Atmosphere
• Human activities

  Increasing the amount of some greenhouse gases
• Greenhouse gas sources

  • Cattle farming - releases methane
  • Farming rice in paddy fields - releases methane
  • Burning fossil fuels in vehicles and power stations - releases CO2
  • Deforestation - releases trapped CO2 and reduces absorption of CO2 through photosynthesis
• Effects of global warming

  • Glaciers and polar ice melting
  • Sea levels rising
  • Rainfall patterns changing producing drought or floods
  • Habitats changing
  • Forest fires, coral bleaching
• Carbon footprint

  The total amount of carbon dioxide (and other greenhouse gases) which are emitted over the full cycle of a product, service or event
• Ways of reducing carbon footprint

  • Fit photovoltaic solar panels - reduces amount of fossil fuel generated electricity
  • Commute to work instead of cars
  • Improve home insulation e.g. 10pt insulation or double glazing - reduces amount of gas burned in boiler
• Pollutant

  Source of (environmental) problems
• Pollutants

  • Carbon dioxide
  • Carbon monoxide
  • Particulate carbon
  • Sulphur dioxide
  • Nitrogen oxides
• Carbon dioxide

  Product of complete combustion of any fuel containing carbon
• Carbon monoxide

  Product of incomplete combustion of any fuel containing carbon
• Particulate carbon

  Product of incomplete combustion of any carbon fuel