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C1-Chemistry in our World
Topic 4-Obtaining and Using Metals
Ores- are rocks which contain compounds of metal in them.
Reactive metals are found as compounds.
Non-reactive metals are found on their own-gold, silver and platinum
Examples of ores:
Ore Compound Metal
Haematite Iron oxide-Fe2O3 Iron-Fe
Malachite Copper carbonate CuCO3 Copper-Cu
Bauxite Aluminium oxide-Al2O3 Aluminium-Al
Galena Lead sulphide-PbS Lead-Pb
Extraction of Metals:
This means removing whatever element is combined with the metal.
Usually the element is oxygen so oxygen is removed.
Removal of oxidation is a type of reaction called reduction.
Addition of oxygen is oxidation- e.g burning, rusting
There are two ways in which a metal can be `reduced' or the oxygen is removed:
1. Heating with carbon
2CuO + C CO2 + 2Cu
2Al2O3 4Al + 3O2
Heating with carbon Electrolysis
Which metals? Low reactivity in the middle High reactivity- top of the reactivity
of the reactivity series series
Examples Irn, copper, zinc, lead, tin Potassium, magnesium, aluminium, sodium,
What do we Carbon or charcoal and Electrolyte- melt the metal
need? strong heat compound
Electrodes positive and negative
The metal goes to the negative electrode
The oxygen goes to the positive electrode
Advantages Cheap, No greenhouse gas is produced
less heat needed, Quicker
carbon is readily available
Disadvantage Releases CO2 which is a Expensive cost of electricity
greenhouse gas Lots of energy needed
Burns more fossil fuels for the electricity
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The demand for metals is increasing with advanced technology and the need for more durable
buildings and machinery. If we continue to use metals at the current level we will soon run
out of the most useful natural resources as well as continue to damage the environment. Is
recycling a solution to this problem?
1. If we do not, we will run out of metals.
2. Metal ores will last longer
3. Less energy needed to recycle than to extract- so less fossil fuels used.…read more