- are linked to the order of reactivity
- Only metals less reactive than carbon can be extracted by a reduction reaction with carbon ----------> heating the ore with carbon monoxide
- more reactive elements form compounds more readily
- reduction= loss of oxygen
- Hydrogen: metals above H react with acids to release H2
Extracting Iron:
(Blast Furnace)
Raw materials:
- Iron ore -----> iron
- Coke -----> almost pure carbon; reducing iron oxide to iron metal
- Limestone -----> take away impurities from slag
- Air ------> allows the coke to burn
Reducing Iron ore to Iron:
- Hot air blasted into the furnace -----> coke burns faster than normal. Raises to 1500C.
- Coke burns and produces carbon dioxide:
- Carbon and Oxygen ------> Carbon Dioxide
- C + O2 ------> CO2
- Carbon monoxide
- Carbon dioxide and Carbon -----> Carbon monoxide
- CO2 + C -----> 2CO
- Carbon monoxide then reduces the iron ore to iron
- Carbon monoxide + Iron(II) oxide ------> Carbon dioxide + Iron
- 3CO + Fe2O3 ------> 3CO2 + 2Fe
- Iron is molten at temperature also dense so goes to the bottom where it's tapped off
Removing impurities:
Slag forms as CaO from limestone reacts with rocks (SiO2)
CaCO3 -----> CaO + CO2
CaO + SiO2 ------> CaSiO3 (molten slag)
- Coolen to solid and used for:
- road building
- fertiliser
Uses of Iron:
- steel
- buildings
- car radio
- railings
REDOX -------> reduction and oxidation occur together
Oxidising Agent --------> produces Oxygen (O2) in the process. reduced itself
Reducing Agent --------> gains Oxygen (O2) in the process. oxidising itself
Rusting of iron:
- needs water and oxygen (from air)
- doesn't rust in boiled water or dried air
How to prevent rusting?
Barrier methods:
- paint
- plastic coat
- tin plate
- grease
- coat in zinc
Sacrificial methods:
- Attach above (more reactive) metal to the iron (e.g. zinc)