Using Resources

• what is a finite resource 


  resources that will be used faster than it can be replenished
• what is a renewable resource

  resources that can be replaced and replenished for current and future generations
• what is a sustainable resource

  meets the needs of the current generation without compromising the ability of future generations meeting their needs
• what is potable water

  water that is safe to drink
• is potable water pure 


  it is not pure it contains dissolved chemicals but they are harmless
• what are the conditions required for potable water

  pH between 6.5 - 7

  no harmful bacteria to cause health issues

  not too many dissolved salts
• describe the water treatment process

  water enters the works and is screened catching large objects

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  enters settlement tank where sand and soil is removed and thrown with help of Al So4 and time clumping dirt together

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  passes through a coarse filter so no dirt remains

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  chlorine, ozone or uv is used to remove the bacteria

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  the pH is tested and corrected if necessary

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  water is now stored ready for consumers
• what is desalination 


  converting sea water to drinking water
• two processes of desalination

  distillation

  reverse osmosis - pressure is applied pushing the sea water against the partially permeable membrane trapping the dissolved ions
• how is the water tested for purity

  after the processes the water is tested for purity

  colbalt chloride paper - turns from blue to pale pink/ white in pure water
• what is screening 


  water enters and passes through a metal grid that traps large objects and grit from the water
• what is sedimentation

  in the first tank solid sediments settle out and piped out / removed

  the effluent, containing microorganism, flow to the next tank
• what is aerobic digestion

  the second tank, oxygen is bubbled in to allow useful bacteria to feed aerobically on the organic matter + harmful microorganisms
• what are the 4 stages of the life cycle assessments

  raw material extraction and processing

  manufacturing and production

  product use and reuse

  end of life disposal
• what should be considered in the LCAs

  how readily available?

  finite or renewable?

  cost effective?

  amount of energy?
• issues with landfill

  more space is needed

  methane is produced - flammable + greenhouse gas = climate change

  unsightly, encourages pests and unpleasant smells
• benefits and issues with incineration

  instant disposal

  must be careful - if toxic materials end there = toxic gases are produced

  heat can be used as energy
• advantages of LCAs


  takes into account all stages of a products life
• disadvantages of LCAs

  it is a bias process - based on an opinion
• what is the main method of obtaining copper

  smelting - copper is heated to a high temp in a blast furnace with air to produce impure copper - then be extracted with anode in electrolysis
• what is bioleaching

  bacteria feed on the low-grade ore

  separated weak bond replacing them with stronger bonds scrap iron and electrolysis then extract the copper
• why are new ways to obtain copper needed

  high-grade ores are running out
• advantages of bioleaching

  very energy effective

  bacteria can live off energy released when breaking bonds
• disadvantages of bioleaching

  very slow process
• explain the process of phytomining


  some plants have the ability to absorb copper from low-grade ores in the soil the plants are burned
• advantages of phytomining

  any land contaminated with low-grade ores can have plants grown on them
• disadvantages of phytomining

  copper is still not pure

  requires electrolysis = not energy efficient
• write the symbol equation for the haber process 


  N2 + 3H2 -> 2NH3
• is the haber process endo or exothermic

  exothermic in forward direction
• what conditions are used in the haber process

  450 degrees

  200 atmospheres

  iron catalyst
• how is ammonia extracted

  the gases move to the condenser when temp is low enough to only condense ammonia
• what happens to the unreacted gases

  N2 + H2 - unreacted gases are recycled back into the reaction
• what are NPK fertilisers made from

  soluble compounds of nitrogen, phosphate and potassium

  promotes plant growth
• what are the three steps to make fertiliser ammonium nitrate

  step 1 - N2 + 3H2 -> 2NH3

  step 2 - NH3 + 2o2 -> HNO3 + H2O

  step 3 - NH3 + HNO3 -> NH5NO3
• why are fertilisers classes as formulations

  fertilisers are a mixture of compounds so they provide all three nutrients
• write a method to make a fertiliser in the lab

  Fill the burete with acid, close tap and ensure acid is level with zero.

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  Measure 25cm3 of ammonia solution in a conical flask and add 5 drops of phenolphthalein

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  Run the acid into the conical flask until it is neutral (pink to colourless).

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  Repeat using the same volumes but without the indicator (for purity).

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  Heat gently to evaporate same liquid - DO NOT heat to dryness.

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  Leave in a basin for a few drops .

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  Filter and weigh the crystals