Chemicals and the Earth

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Chemicals and the Earth

• Lesson 3 Extraction of Metals

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Lesson 3 Objectives

• Talk about native metals and ores
• Look at the three methods of extraction
• Introduce table of extraction of metals

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Recap on last lesson

• Oxidation is the addition of oxygen (or loss of
  electron)
• Reduction is the loss of oxygen (or gain of
  electron)
• OIL RIG

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Thermit Reaction

• aluminium iron(III)oxide
• iron aluminium oxide
• identify what is being oxidised and what is
  being reduced? Hence what is the reducing or
  oxidising agent?

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Metals and Metal Ores

• Metals that are found uncombined in nature are
  called native metals.
• Give an example of native metal? Why ?
• Most metals are found in compounds and are not
  native. Rocks from which they can be separated
  are called ores

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Ores

• A rock is a mixture of minerals. A mineral is any
  solid compound or ore found naturally in the
  earths crust.
• Examples haematite (iron), malachite (copper),
  bauxite (aluminium)

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How are metals released from their compounds
(ores)?
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Methods of extraction

• 1) by heat alone thermal decomposition
• silver oxide sliver oxygen
• 2) by heating with carbon
• copper carbon copper carbon
  oxide dioxide

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Extracting metals from ores

• The extraction of metals from ore involves
  always a chemical reaction to release the metal
  from its compounds
• Extraction of metals can also be described as a
  reduction. Many ores are oxides this means
  removing oxygen to release the metals

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Methods of extraction

• 3) by electrolysis
• Passing electricity through a molten ore will
  split up the compound and so extract the metal.
  Electrical energy decomposes the compounds and
  reduces the ore
• aluminium oxide aluminium oxygen

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Extraction in terms of the Reactivity Series

• Metals higher than carbon are extracted using ?
• Metals below carbon are extracted using?
• Mercury and Silver

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questions sheet

• Answer question 1 ,2 ,3 on sheet
• Hand in exercise books at end of lesson !!