C10 - using resources

• what do humans use the earths resources for?

  warmth, shelter, food and transport
• why must human activities be suitable?

  provides new products sustainability to need the needs of this generation without compromising the needs to the next generation
• how are natural resources formed?

  agriculture
• what are natural resources used for?

  provide food, timber, clothing and fuels
• how can natural resources be improved?

  by replacing then with synthetic alternatives

  e.g. rubber is made by the sap of a tree
• what is a finite resource?

  a non-renewable resource that cannot be replaced at the same rate it is used up
• what are some examples of finites resources?

  fossil fuels

  metals
• what are the main risks of extracting finite resources?

  have to balance the social, economic and environmental impacts of extraction

  bad for the environment - produces waste, destroys habitats and uses lots of energy
• what is potable water?

  water that is safe to drink - contains small amounts of dissolved solids
• what is pure water?

  water that contains only H2O molecules only
• how is water collected in the UK?

  through rain that collects as surface water or as groundwater
• how is potable water produced?

  choosing an appropriate source of fresh water

  passing the water through filter beds

  sterilising
• how is potable water sterilised?

  sterilising agents such as chlorine, ozone or ultraviolet light
• how do dry countries collect potable water?

  sea water must be treated by desalination
• how can desalination be done?

  distillation or by the process that uses membranes such as reverse osmosis
• how is water wasted?

  lifestyle process - having a bath, washing machines, goes into sewers

  agricultural processes - nutrient run-off from fields and slurry form animal farms
• what needs to be removed?

  sewage and agricultural waste water - large solid particles, grit, harmful microbes, organic matter

  industrial water water - harmful chemicals, organic matter
• what are the stages of sewage treatment?

  • before being screened - large bits of material are removed
  • undergoes sedimentation - forms one heavier layer of sludge and a lighter layer of effluent
  • effluent is removed and treated by aerobic respiration
  • sludge is removed - transferred to large tanks - broken down through aerobic respiration
  • anaerobic respiration breaks down the organic matter and releases methane
  • methane is used as an energy source and the remaining waster is used as fertiliser
  • waster water containing toxic substances it treated further by adding chemicals
• what are alternative methods of extracting copper from its core?

  bioleaching - uses bacteria to convert copper compounds into soluble leachate that is electrolysed to separate the copper ions

  phytomining - grows plants in soil that contain copper, plants grow and copper builds in leaf, plants are harvested, dried and burned, the ash contains soluble copper compounds which are extracted
• what are the issues with these methods?

  takes lots of time so are impractical
• what is the method of desalination?

  • test the pH using a meter - neutralise it its too high or too low
  • test the water for sodium chloride
  • distill the water using distillation apparatus
  • retest the distilled water for sodium chloride and the pH
• what are the issues with desalination?

  expensive so it is impractical in producing large quantities of fresh water
• what is the life cycle assessment?

  carried out to assess the environmental impact of products in four stage
• what are the 4 stages of the life cycle assessment?

  1. extracting and processing the raw material
  2. manufacturing and packaging
  3. using the product
  4. product disposal
• what is the LAC for a plastic bag?

  • crude oil
  • compounds used to make plastics are extracted from fractional distillation, cracking then polymerisation
  • can be reused
  • recyclable
• what is the LCA for a paper bag?

  • timber
  • pulped timber is processed using lots of energy, lots of waste is produced
  • used once
  • biodegradable, non toxic and can be recycled
• what are the issues with carrying out LCA's?

  can be biased

  aren't entirely numerical - effect of pollution cannot be accurately measured
• why are recycling and reusing important?

  reduced the use of limited resources, use of energy sources, waste and environmental impacts
• how can glass bottles be recycled?

  can be reused without shaping

  recycled for other products
• how does glass recycling work?

  glass is crushed then melted to be reshaped
• how are metals recycled?

  melting and recasting/reforming into different products
• why is it important to recycle metals?

  uses less energy than mining and extracting so is cheaper

  reducing fossil fuel usage

  less metal sent to landfill
• what is corrosion?

  the destruction of materials by chemical reactions with substances in the environment
• what is the rust that forms from the corrosion of iron?

  hydrated iron (III) oxide
• what is the equation for the corrosion of iron?

  iron + water + oxygen -> hydrated iron (III) oxide
• how can we prevent rust?

  coat the iron with a protective barrier

  sacrificial protection
• what is bronze an alloy of?

  copper and tin
• what is bronze used for?

  metals, ornaments and statues
• what is brass an alloy of?

  copper and zinc
• what is brass used for?

  more malleable than copper so used where lower friction is involved