5.3 Extracting Metals Flashcards
Where are metals found
- In the Earth’s crust
- most metals are combined chemically with other elements such as oxygen and sulphur
- metal must be chemically separated from its compounds before it can be used
Metal ore def
Rock which contains enough metal to make it economically worthwhile to extract the metal
How can metals be extracted
- copper ores grounded up to powder
- mixed with water and a chemical that makes the copper compound repel water
- air is bubbled through mixture and copper compound floats on top as a froth
- rocky bits sink, concentrated copper is scraped off the top
- it is ready to have its copper extracted
Which metals are found in the earth as elements and why
Gold and sliver because they are unreactive
How is gold separated from sand and rocks
By panning
How is carbon used to extract metals
- Carbon will displace less reactive metals from their oxides
- carbon is used to extract some metals from their ores
Explain the method to reduce an oxide with carbon
- heat metal oxide with carbon
- carbon removes the oxygen from the metal oxide to form carbon dioxide
- metal is also formed
Complete the equation:
metal oxide + carbon —>
metal oxide + carbon —> metal + carbon dioxide
What does the acronym OIL RIG
Oxidation
Is
Loss
Reduction
Is
Gain
How is tungsten extracted by reduction
- hydrogen is used for reduction because tungsten obtained with hydrogen is very pure
tungsten oxide + hydrogen —> tungsten + water (steam)
How are metals that are more reactive than carbon extracted
Electrolysis
Electrolysis def
The breakdown of a substance containing ions by electricity
When is it worth extracting a particular metal
- how easy it is to extract
- how much metal the ore contains
- Changing demands for a particular metal
A cheaper method could be introduced
