last minute p1 chem

• positives of both bio-leaching + phytoextraction

  • less damage to landscape/ environment than mining
  • conserves supplies of higher grade ores
  • no harmful gases such as sulfur dioxide are produced
• negatives of both bio-leaching + phytoextraction

  • both very slow
• positives of just bio-leaching

  • does not require high temperatures
• negatives of just bio-leaching

  • toxic substances + sulfuric acid damage environment
• positives of just phytoextraction

  • can extract metals from contaminated soils
• negatives of just phytoextraction

  • more expensive than mining ores
  • growing plants is dependent on weather conditions
• rules for electrolysis: solution not molten

  • if metal = copper, then get copper
  • if metal is not copper, then get hydrogen as hydrogen accepts electrons more easily + other metal donates electrons more easily
  • if non-metal is a halogen, get a halogen
  • if not a halogen, get oxygen
• what are the half equations for the electrolysis of copper sulfate using COPPER electrodes

  • anode: $Cu$$\rightarrow$$Cu^{2+}$$+$$\ 2e^-$
  • cathode: $Cu^{2+}$$+$$\ 2e^-$$\rightarrow\ Cu$
• what are the half equations for copper sulfate using GRAPHITE electrodes

  $Cu^{2+}$$+$$\ 2e^-$$\rightarrow\ Cu$: cathode

  $4OH^-$(aq) $\rightarrow O_2\$(g) + $2H_2O$ (l) + $4e^-$
• how does bio-leaching work?

  • bacteria grown on low grade ore
  • bacteria produces liquid solution containing copper ions: leachate
  • copper is the extracted from leachate by displacement
  • using scrap iron + purified by electrolysis
  • can be used for nickel, zinc + lithium
• how does phytoextraction work?

  • growing plants that absorb metal compounds
  • burn the plants to form ash
  • then extract metals from ash
• Please stop calling my aunt cranky Zelda in hospital- reactivity series (most to least)

  • potassium
  • Sodium
  • calcium
  • magnesium
  • aluminium
  • carbon
  • zinc
  • iron
  • hydrogen
  • copper
  • silver
  • gold
• metal + water -> metal hydroxide + hydrogen
• describe the test for oxygen

  • use a glowing wooden splint
  • insert into test tube of unknown gas
  • if unknown gas = oxygen, split will relight
• describe the test for chlorine gas

  • use damp blue litmus paper
  • chlorine gas will bleach litmus paper if present
• which metals are extracted using electrolysis?

  • metals higher than carbon in reactivity series
  • Potassium, sodium, calcium, magnesium, aluminium
• which metals are extracted by reduction (OILRIG) using carbon

  • metals below carbon in reactivity series
  • Zinc, Iron, Tin, Copper + (silver)
• define a metal ore

  a rock that contains enough metal to make it economically worthwhile extracting the metal from it
• 6 marker: considering all three substances: diamond, graphene + fullerene C60

  • all structures: carbon atoms bonded by single covalent bonds, strong bonds: shared pair of electrons

  DIAMOND:

  • each carbon atom = joined to 4 others
  • giant covalent structure
  • a lot of energy to overcome bonds so high melting point
  • no free electrons
  • so diamond does not conduct
  • strong covalent bonds so strong material

  GRAPHENE

  • giant covalent structure
  • each carbon atom joined to 3 others
  • lots of strong covalent bonds so strong material + high melting point to overcome strong bonds
  • one free electron: delocalised so conducts electricity

  FULLERENES

  • molecular structure
  • weak intermolecular forces between molecules
  • low melting point: less energy needed to separate molecules + overcome weak intermolecular forces
  • one free electron: delocalised so semi conduct electricity
  • only across surface of molecule
  • no/little movement of electrons
• acid + metal oxide -> salt + water
• acid + metal hydroxide -> salt + water
• acid + metal -> salt + hydrogen
• acid + metal carbonate -> salt + water + carbon dioxide