Resources

• How humans use the earth's resources

  • Provide warmth
  • Provide shelter
  • Provide food
  • Provide transport
• Modern agriculture


  Allows us to grow enough cotton to meet the needs of the world
• Resources used for fuel

  • Biofuels such as wood chips
• Chemistry


  Has replaced natural resources with synthetic alternatives
• Synthetic alternative to natural rubber

  • Produced using crude oil
• Finite resources


  Cannot be replaced as quickly as they are being used
• Finite resources


  • Fossil fuels
  • Metals
• Renewable resources


  Can be replaced as quickly as they are used
• Renewable resource


  • Wood
• Sustainable human activities


  Meet our needs without preventing future generations from meeting their needs
• Role of chemistry


  • Provides artificial fertilizers to grow more food
  • Provides safe drinking water
  • Enables more efficient metal extraction through processes like phyto mining and bio leaching
• Potable water


  Water that is safe to drink
• Pure water


  Water that contains no dissolved substances at all
• Drinking water must have sufficiently low levels of dissolved salts such as sodium chloride and low levels of microbes such as bacteria
• Producing potable water from fresh water

  1. Use a good source of fresh water

  2. Pass the water through filter beds to remove material such as leaves and suspended particles

  3. Sterilize the water to kill microbes (using chlorine, ozone or ultraviolet light)
• Producing potable water from salty water

  1. Use desalination to reduce the levels of dissolved minerals to an acceptable level

  2. Desalination can be done by distillation or reverse osmosis
• Desalination and reverse osmosis require very large amounts of energy, making them expensive
• Sources of fresh water

  • Aquifers
  • Lakes
  • Rivers
  • Reservoirs
• In the UK, rain water provides most of the potable water, which then collects in the ground, lakes, rivers and reservoirs
• In many places, fresh water is scarce, so the only available water may be too salty to drink, such as seawater
• Wastewater treatment


  1. Screening through mesh to remove solids and grit

  2. Sedimentation in tanks to produce liquid effluent and sludge

  3. Anaerobic digestion of sludge to produce biogas

  4. Aeration of liquid effluent to allow aerobic bacteria to digest organic matter and microorganisms

  5. Discharge of treated liquid effluent to environment
• Wastewater contains large amounts of organic molecules and harmful microorganisms that need to be reduced before discharge
• Industrial wastewater may contain harmful chemicals that need to be removed before entering general sewage treatment
• Treated sewage is not directly used to produce potable water in the UK
• Wastewater treatment questions can be found in the revision workbook