Using resources

• What do we use Earth's resources for?


  To provide warmth, shelter, food, and transport
• How do natural resources contribute to our needs?


  They provide food, timber, clothing, and fuels
• What are finite resources?

  Resources that have a limited supply and will eventually run out
• What role does chemistry play in sustainable development?

  Chemistry improves agricultural and industrial processes for new products
• What is sustainable development?

  Development that meets current needs without compromising future generations
• What are renewable energy resources?

  Sources of power that quickly replenish themselves
• When do plants/wood count as renewable resources?

  When they continue to be re-planted
• What is potable water?


  Water that is safe to drink
• Why is potable water not considered 'pure'?


  It contains dissolved substances but must have low levels of salts and microbes
• What factors influence the methods used to produce potable water?

  Available supplies of water and local conditions
• What is an appropriate source of fresh water in the UK?

  Rainwater that collects in the ground, rivers, and lakes
• What is the purpose of filter beds in water treatment?

  To remove different sized insoluble solids
• How is water sterilised in the treatment process?

  By using sterilising agents like ozone, UV light, or chlorine
• What is required if only salty or sea water is available?

  Desalination
• What are the two methods of desalination mentioned?

  Distillation and processes with membranes (e.g., reverse osmosis)
• Why are desalination methods considered expensive?

  Both distillation and membrane processes are very costly
• Why is water of correct quality essential for life?

  It must be free of poisonous salts and harmful microbes
• What are the steps in producing correct quality water?

  
  

  SCREENING

  SEDIMENTATION

  ANAEROBIC DIGESTION (sludge)

  AEROBIC DIGESTION (effluent)
• Why is it cheaper to obtain potable water from groundwater and wastewater?

  It is relatively cheaper and easier than from salt water
• What is the status of Earth's resources of metal ores?

  They are limited
• Why are copper ores becoming scarce?

  Because they are being depleted
• What are the new methods of extracting copper from low-grade ores?

  Phytomining and bioleaching
• How can metal compounds be processed to obtain metals?

  By displacement using scrap iron or by electrolysis
• What is one example of a metal that can be obtained from solutions of copper compounds?

  Copper
• screening


  remove large insoluble solids
• sedimentation


  screened waste stands in a sediment tank

  heavier suspended solids sink --> sludge

  effluent on the top
• anaerobic digestion


  release methane to produce biogas and fertiliser
• aerobic digestion


  air is pumped, bacteria breaks down organic matter to produce portable water
• advantages of waste water

  requires less energy
• disadvantages of waste water

  people don't want to drink waste water
• distillation methods


  heat salt water until it evaporates

  water vapour is cooled and condenses

  distilled water is collected
• reverse osmosis


  put salt water under very high pressure

  pure water passes through partially permeable membrane

  salt and dissolved substances cannot pass
• stages of fresh water treatment


  choose a source

  filtration

  streilisation
• choose a source (freshwater)


  with low levels of dissolved substances
• filtration (freshwater)


  remove insoluble solids with wired mesh
• sterilisation (freshwater)


  destroy harmful microbes

  use UV, chlorine or ozone
• sea water


  is saline and has high levels of dissolved salts
• domestic


  water from baths, toilet, washing machines, sinks etc
• agricultural


  runoff from fields which contain chemicals (fertilisers)
• industrial


  may contain harmful chemicals so has to undergo treatment stages