Using resources

• What are ceramics?


  Non metal solids with high melting points that are not made from carbon based compounds
• what are composites ?

  • a substance made of one material embedded in another, fibres or fragments of a material (known as the reinforcement) are surrounded by a matrix acting as a binder
  • the properties of a composite depend on the properties of the material it is made from
• what 2 things influence the properties of a polymer

  How it’s made

  What its made from
• the Monomers that a polymer is made from determine the type of bonds that form between the polymer chains

  The weak bonds between the different molecule chains determine the properties of the polymer
• thermosoftening polymers:

  • contain individual polymer chains entwined together with weak forces between the chains
  • you can melt and remould these plastics
• thermosetting polymers

  • contain monomers that form cross-links between the polymer chains, holding the chains together in a solid structure
  • they do not soften when heated
  • strong, hard and ridgid
• ceramics (include glass and clay ceramics)

  • insulators - of heat and electricity
  • brittle
  • stiff
• polymers

  • Insulators- heat and electricity
  • Flexible
  • Easily moulded
• metals

  • malleable
  • good conductors of heat and electricity
  • ductile
  • shiny
  • stiff
• Pure metals often do not have the properties required

  • the regular structure makes them too soft
  • alloys are often a better fit as the structure is disrupted and they are harder
• what is corrosion?


  Chemical reaction that deteriorates a material, often due to exposure to moisture or chemicals.
• iron, (corrosion)

  • iron corrodes easily (rusts)
  • rust is just the compound hydrated iron(III) oxide
  • corrosion only happens on the surface of a material, where its exposed to air
  • rust is a soft crumbly solid that soon flake off to leave more iron exposed out again, this means eventually all the iron in an object corrodes away even if it wasn’t initially exposed
• both air and water are needed for iron to rust
• the 2 main ways to prevent rusting

  • coat the iron with a barrier:
  • painting
  • electroplating (uses electrolysis to reduce metal ions to reduce metal ions onto an iron electrode, can be used to coat iron with another metal that wont corrode)
  • oiling
  • sacrificial method- involves placing a more reactive metal (e.g. zinc) with the iron, water and oxygen react with the sacrificilal metal instead of the iron
• What are renewable resources?

  resources that replenish at a faster rate than we use them
• what are finite resources?

  a resource that has limited quantities and cannot be replenished quicker than we are using it
• the stages of LCA (life cycle assessment)

  1. getting the raw materials-
  2. manufacture and packaging
  3. using the product
  4. product disposal
• what is the LCA(life cycle assessment) ?

  an analysis that looks at every stage of a products life to asses the impact it would have on the environment
• what is potable water?

  Safe and drinkable water.
• the process of collecting potable water

  • rainwater is a type of freshwater
  • when it rains water can either collect as surface water (rivers, lakes etc) or as groundwater (in rocks called aquifers that trap water underground
• treating water from fresh water sources:

  • filtration- a wire mesh screens out large twigs etc, then gravel and sand beds filter out any other solid particles
  • sterilisation- the water is sterilised to kill any harmful bacteria or microbes, this can be done by bubbling chlorine gas through it or by using ozone or UV light
• what is fresh water?

  water that doesn’t have much or has nothing dissolved in it
• treating sea water:

  • destillation- can be used to desalinate sea water
  • reverse osmosis- the salty water is passed through a membrane that only allows water molecules to pass through, ions and larger molecules are trapped by the membrane and so separated from the water
• what is waste water?

  Contaminated water.
• sewage treatment requires more processes than treating fresh water but less energy than desalinating sea water, so it could be used as an alternative in areas where there is not much fresh water
• What is the haber process?

  Industrial process for producing ammonia from nitrogen and hydrogen.
• what are the raw materials for the haber process

  nitrogen, hydrogen
• The Haber process:

  1. The purified gasses are passed over a catalyst of iron at a high temperature (around 450 Celsius) and a high pressure (about 200 atmospheres)
  2. Some of the hydrogen and nitrogen react to form ammonia
  3. The reaction is reversible so some of the ammonia produced breaks down into nitrogen and hydrogen
  4. Upon cooling the ammonia liquefies and is removed
  5. The remaining hydrogen and nitrogen are recycled
• Factors that effect the rate of equilibrium (e.g. temperature) can also effect the position of equilibrium for a reversible reaction- and sometimes there is a trade off between increasing rate and maximising the yield of a reaction
• Compounds of nitrogen, phosphorus and potassium are used as fertilisers to improve agricultural productivity. NPK fertilisers contain compounds of all 3 elements
• NPK fertilisers can be achieved using a variety of raw materials in several integrated processes
• NPK fertilisers are formulations containing salts of nitrogen, phosphorus and potassium (hence NPK) in the right percentages of the elements
• Ammonia can be used to manufacture ammonium salts and nitric acid.

  Potassium chloride, potassium Sulfate and phosphate rock are obtained by mining but phosphate rock cannot be used directly as a fertiliser.

  Phosphate rock is treated with nitric acid or sulphuric acid to produce soluble salts that can be used as fertilisers
• What are the salts produced when phosphate rock reacts with nitric acid?

  phosphoric acid and calcium nitrate
• What are the salts produced when phosphate rock reacts with Sulphuric acid?

  Calcium sulphate and calcium phosphate
• What is the salt produced when phosphate rock reacts with phosphoric acid?

  Calcium phosphate
• Producing fertilisers in industry:

  • Reaction is carried out in giant vats at high concentrations resulting in a very exothermic reaction
  • The heat released is used to evaporate water from the mixture to make a very concentrated ammonium nitrate product
• Producing fertilisers in a lab :

  • The reaction is carried out on a much smaller scale by titration and crystallisation
  • The reactants are at a much lower concentration than in industry so less heat is produced by the reaction and it is safer for a person to carry out
  • After the titration the mixture needs to be crystallised to give pure ammonium nitrate crystals
  • Crystallisation is not used in industry as it is very slow
• the 2 ways to clone plants :

  Tissue culture and cuttings