c6.1

• Carbon is used for extracting metals from their compound (metal oxide) by reduction,

  • works for less reactive metals
  • produces pure metal + carbon dioxide
  • key conditions- carbon must be less reactive then metal and only works with specific metals in reactivity series.
• extraction of metals


  most metals are only found as compound because the metal has reacted with other elements in the past because of this the metal has to be extracted from the ore(rock) where the metal compound is found
• carbon is used to extract metal from their oxide because it is:


  • cheap
  • high abundance
• metals that are less reactive than carbon can be extracted using a reduction reaction with a carbon
• in a reduction reaction with carbon, a metal oxide loses oxygen to form a pure metal
• Electrolysis requires large quantities of energy to melt the solid ionic compound so the ions are free to move and to provide the electrical current.
• electrolysis


  • when an ionic compound is melted or dissolved in water,the forces of attraction are broken and ions are free to move.
  • these liquids are solutions can now conduct electricity
  • scientist call these liquids or solutions electrolytes
• an ore is a rock or mineral eg malachite that contains enough metal to make it economical to extract the metal.

  the value of the metal is more then the cost of extracting it. Different metal compounds are found in different ores.

  
• chemical processes

  • Oxidation: Gaining oxygen or losing electrons
  • Reduction: Losing oxygen or gaining electrons

  Example:

  • Oxidation:$\textrm{2Mg} +$$\textrm{O}_2 \rightarrow \textrm{2MgO}$(Magnesium gains oxygen)
  • Reduction:$\text{MgO} \rightarrow \text{Mg} +$$\text{O}_2$(Magnesium loses oxygen)
• Key point: Most metals react with oxygen in the atmosphere, creating metal oxides they dont typically exist in their form.

  can be found bonded with oxygen

  eg iron oxide(rust)
• gold is often found in its pure form in nature, since is it unreactive and doesnt form metal oxide
• Metal extraction involves removing oxygen from metal oxides to get pure metals.
• methods of metal extraction

  1. Reduction with Carbon

  • Cheapest method
  • Works for less reactive metals
  • Carbon takes oxygen away from metal oxide

  1. Electrolysis

  • Used for more reactive metals
  • Very energy-intensive
• reactivity determines

  • How easily a metal loses electrons
  • How readily it forms compounds
  • Which extraction method works