Extraction of metals

• Only active metals such as gold are found in the earth as the metal itself
• Gold is so unreactive we can find gold nuggets directly in the earth
• Oxide


  Compound where a metal has reacted with oxygen
• With other metals, they are found in the earth's crust in the form of oxides
• More reactive element


  Can push out or displace a less reactive element from its compound
• The reactivity series orders elements from most reactive to least reactive
• Magnesium is more reactive than iron


  Magnesium can remove oxygen from iron oxide
• Reduction


  Losing oxygen
• Oxidation


  Gaining oxygen
• Extracting iron from iron oxide using carbon


  Carbon + iron oxide -> carbon dioxide + iron
• The reactions in a blast furnace are more complicated than the simple displacement reactions shown
• Displacement reactions


  • Magnesium + lithium oxide -> magnesium oxide + lithium

  1. Calcium + zinc oxide -> (impossible)
  2. Carbon + copper oxide -> carbon dioxide + copper
• Reaction 2 is impossible because zinc is less reactive than calcium
• In reaction 1


  Magnesium is reduced (loses oxygen), lithium is oxidized (gains oxygen)
• In reaction 3


  Copper is reduced (loses oxygen), carbon is oxidized (gains oxygen)