Transcript Chemicals and the Earth

Chemicals and the Earth
Lesson 3: Extraction of Metals
Lesson 3 Objectives
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Talk about native metals and ores
Look at the three methods of
extraction
Introduce table of extraction of metals
Recap on last lesson
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Oxidation is the addition of oxygen (or
loss of electron)
Reduction is the loss of oxygen (or gain
of electron)
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OIL RIG
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?
Metals and Metal Ores
Metals that are found uncombined in
nature are called native metals.
Give an example of native metal? Why ?
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Most metals are found in compounds
and are not native. Rocks from which
they can be separated are called ores
Ores
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A rock is a mixture of minerals. A
mineral is any solid compound or ore
found naturally in the earth’s crust.
Examples: haematite (iron), malachite
(copper), bauxite (aluminium)
How are metals released
from their compounds
(ores)?
Methods of extraction
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1) by heat alone: thermal decomposition
silver oxide
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sliver + oxygen
2) by heating with carbon
copper +carbon
copper + carbon
oxide
dioxide
Extracting metals from
ores
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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
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
Extraction in terms of the
Reactivity Series
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Metals higher than
carbon are extracted
using ?
Metals below carbon
are extracted using?
Mercury and Silver
questions sheet
Answer question 1 ,2 ,3 on sheet
Hand in exercise books at end of lesson !!