3) Extraction of metal and reduction

•  The method of extraction of a metal depends on how reactive it is.
•  Unreactive metals (e.g. gold) exist as elements at the Earth's surface.
• However, most metals are found as metal oxides, or as compounds that can be easily changed into metal oxides.
•  Metals that are less reactive than carbon (e.g. iron and lead) can be extracted from their oxides by heating with carbon:

  iron oxide + carbon-iron + carbon dioxide

  The iron oxide loses oxygen, so it is reduced.

  The carbon gains oxygen, so it is oxidised.