Sources of metals
- The Earth’s crust contains metals and metal compounds such as gold, copper, iron oxide and aluminium oxide
- Useful metals are often chemically combined with other substances forming ores
- A metal ore is a rock that contains enough of the metal to make it worthwhile extracting
- They have to be extracted from their ores through processes such as electrolysis, using a blast furnace or by reacting with more reactive material
- In many cases the ore is an oxide of the metal, therefore the extraction of these metals is a reduction process since oxygen is being removed
- Common examples of oxide ores are iron and aluminium ores which are called haematite and bauxite respectively
- Unreactive metals do not have to be extracted chemically as they are often found as the uncombined element
- This occurs as they do not easily react with other substances due to their chemical stability
- Examples include gold and platinum which can both be mined directly from the Earth’s crust
Examiner Tip
A metal can reduce another metal (remove oxygen) only if it is more reactive than the metal that is bonded to the oxygen.
