Metals Flashcards
Define MINERALS
Minerals are naturally occurring compounds
What is a METAL ORE?
A metal ore contains metal compounds (reactive) and unwanted rock. The metal must be extracted from its ore.
What factors increase the cost of the metal?
- the ore is difficult to obtain
- the method of extraction is expensive
- the ore contains a low percentage of the metal
What is the word equation for when a metal is heated with carbon?
iron oxide + carbon –> carbon dioxide + iron
What is the word equation for when a metal is extracted by electrolysis?
aluminium oxide —electricity—> aluminium + oxygen
How do scientists know whether a metal must be extracted using electrolysis or whether to heat the ore with carbon?
The reactivity series shows which metals are more reactive than carbon and so therefore must be extracted using electrolysis
Define OXIDATION
A reaction in which molecules gain oxygen and become oxides
Define REDUCTION
A reaction where the oxygen is removed from the compound
What is the relationship between reactivity and rate of oxidation?
The more reactive a metal is, the more rapidly it becomes oxidised
How do metals prevent corrosion?
They form and impermeable layer of metal oxide
What is the process SACRIFICIAL PROTECTION?
It is when iron is coated with zinc, a more reactive metal (galvanising). The zinc corrodes first, protecting the iron
What is an ALLOY?
It is a mixture of different metal atoms, alloying changes the properties of the metal
What does carbon do when added to a metal?
Makes the metal harder, stronger and more brittle
What does chronium do when added to a metal?
Makes the metal corrosion resistant
What does titanium do when added to a metal?
Makes the metal stronger, lighter and more corrosion resistant
