By heating it
By adding water to it
By neutralising excess acidity
Clay, sand and crushed rock
Soda, sand and crushed rock
Cement, sand and crushed rock
It is strong when stretched.
It is strong when squashed.
It is worn away by acid rain.
There is a lot of dust and noise.
There is employment for local people.
It causes acid rain.
It is transparent.
It is tough and difficult to break.
It can trap too much heat in a building in the summer.
Gold is more reactive than silver.
Gold is very unreactive.
Gold is very rare.
Aluminium is more reactive than carbon.
Aluminium is less reactive than carbon.
Aluminium is an expensive metal.
Iron is more reactive than carbon.
Iron is less reactive than carbon.
Iron is a cheap metal.
It has a low density and is a good conductor of electricity.
It is shiny and is a good conductor of heat.
It is a good conductor of electricity and heat.
It is oxidised to form iron.
It is electrolysed to form iron.
It is reduced to form iron.
Low carbon steel
High carbon steel
Because layers of atoms can slide over each other easily.
Because layers of atoms cannot slide over each other easily.
Because their atoms are denser and harder than those of pure metals.
They are dull.
They are good conductors of electricity.
They are on the right hand side of the periodic table.
Reduction in a blast furnace
It is an unreactive metal.
It has a thin layer of aluminium oxide on its surface.
It reacts with oxygen but not with water.
It resists corrosion.
Several stages are involved.
Its ore is rare.