Extracting metals T4

• define the structure of metallic bonding

  strong force of attraction between delocalised electrons and metal cation
• how can metals conduct electricity

  the delocalised electron carries an electrical current
• what do metals have and why

  strong forces of electrostatic attraction. they hold the atom together in regular patterns. Means they have high MP and BP because lots of energy is needed to overcome the attraction
• do metals react with air

  metal + oxygen = metal oxide
• how can metals reacting with air be seen

  rust and colour change
• properties of metals

  conducts electricity (has delocalised electron), malleable (layers can slide), forms alloys, sonorous
• what is oxidation

  loss of electrons / gain of oxygen
• what is reduction

  gain of electrons / loss of oxygen
• test for hydrogen

  lit splint burns with a squeaky pop
• test for oxygen

  relights a burning splint
• test for carbon dioxide

  limewater goes cloudy
• what is displacement

  more reactive metal replaces a less reactive metal from its compound
• what do carbon and hydrogen do to less reactive metals

  displaces less reactive metals compared to itself. carbon and hydrogen both oxidised when they reduce the metal oxide.
• what are alloys? and why are they harder than pure metals?

  alloys contain 2 or more different elements. they are harder because the layers are disrupted and cannot slide over eachother.
• how do metals react with water

  metal + water = metal hydroxide + hydrogen
• who reacts vigorously with water

  very reactive metals (K, Li, Ca)
• who doesn't react with water

  copper
• how can metals be extracted from its ore

  can be extracted chemically using reduction with carbon. When ore is reduced, oxygen is removed. e.g. FeO + C -> Fe + CO
• who can carbon reduce. K, Na, Li, Ca, Mg, Al, C, Zn, Fe

  less reactive metals compared to itself. The ones above are extracted using electrolysis. Reduces Zn and Fe
• how can low grade ores be extracted

  phytomining and bioleaching
• what is bioleaching

  using bacteria to seperate metals from ores.
• process of bioleaching

  bacteria is grown on thee low grade ore, biological + chemical processes of bacteria form a solution called leachate. leachate is rich with copper ions. can extract the copper from leachate with displacement reaction with iron or electrolysis. (Fe + CuSO4 -> FeSO4 +Cu)
• advantages and disadvantages of bioleaching.

  + high temps not needed

  + no harmful gases

  + less damage to environment

  + preserved supplies of high grade ores

  -very slow

  -toxic substancees

  -damages environment
• what is phytomining

  using plants to extract metals from soil
• process of phytomining

  there are slag heaps of discarded waste from processing of copper rich ores. copper ions are absorbed by plants using roots. plants are burnt. ash has high % of copper. sulfuric acid added to ash. can be extracted by displacement reaction with iron or electrolysis
• advantages and disadvantages of phytomining.

  +preserves high grade ores

  + less damage to environment

  + no harmful gases produced

  -very slow

  -dependant of weather

  -high temps needed for burning

  -expensive
• what are ores

  contains enough metals to extract for profit
• what are haematite

  iron oxide ores
• what are malachite

  copper carbonate ores
• what are bauxite

  aluminium oxide ores
• native state metals

  unreactive metals that are found uncombined and unreacted
• how are reactive metals found

  in compounds chemically combined with non-metals
• benefits of recycling 1

  conserves resources and energy-> extracting raw materials can take up lots of energy and most of them come from fossil fuels. recycling therefore saves energy and conserves finite resources and allows future generations to use them.
• benefits of recycling 2

  protects the environment-> cuts down the amount of rubbish ending up on landfill sites. they can destroy habitats. so recycling => less fossil fuels are burnt, so less CO2. SO2 cannot be produced. (SO2 => global warming and acid rain)
• benefits of recycling 3

  economic benefits-> extracting materials require more energy than recycling. there for this saves money and also creates jobs.
• benfits of recycling metals

  • cheaper
  • ores are conserved
  • less waste metals in landfill sites
  • less fossil fuels used = less CO2 = less combustion = less pollution
• stages of life cycle assesment

  1. extracting raw materials
  2. manufacturing + distributing
  3. using the product
  4. disposal
• define corrosion

  destruction of materials by chemical reactions with substances in th environment
• what is an example of corrosion

  rusting
• who can rusting happen to

  only iron and alloys of iron like steel