Extracting Metals Flashcards
All 6 cards in this deck
Which metal is usually found uncombined (native) in the Earth's crust: calcium, gold, iron or magnesium?
Gold. The others are too reactive and are found chemically combined.
In terms of oxygen, what are oxidation and reduction?
Oxidation is gain of oxygen; reduction is loss of oxygen.
In , which substance is oxidised and why?
Carbon — it gains oxygen to form carbon dioxide.
Why can iron be extracted by heating iron oxide with carbon?
Iron is less reactive than carbon, so carbon reduces the iron oxide.
Why is aluminium extracted by electrolysis rather than by heating its oxide with carbon?
Aluminium is high in reactivity (aluminium oxide is very stable), so aluminium oxide cannot be reduced by carbon.
Why is electrolysis not used to extract iron?
Electrolysis is expensive / needs a large amount of electricity; heating with carbon is cheaper.