extracting metals Flashcards
how can copper be extracted from copper(ii) sulfate?
stage 1) the copper sulfide is ‘roasted’ in air to form copper oxide and sulfur dioxide
stage 2) the copper oxide is heated with carbon to form carbon dioxide and copper
how can you reduce copper oxide with charcoal
1) mix the two powders in a crucible. The lid must be kept on to prevent escaping powders
2) heat the crucible to begin the reaction then let it cool
3) when the crucible cools, transfer the contents to a beaker of water
4) the copper will sink to the bottom
5) separate the copper by washing it
what is the name of iron ore
haematite
what is coke
impure carbon made by heating coal in the absence of air
why is limestone used
to purify iron
what is the formula for limestone
CaCO3
why isn’t carbon dioxide an effective reducing agent
carbon dioxide is too weak to be an effective reducing agent so carbon monoxide is produced instead
how is carbon monoxide produced? (2 steps)
coke burns in (hot) air making carbon dioxide:
C + O2 —> CO2
the excess coke reacts with the carbon dioxide making carbon monoxide:
C + CO2 —> 2CO
how is iron(iii) oxide reduced?
the carbon monoxide reduces it at 1500C :
3CO + Fe2O3 —> 2Fe + 3CO2
what is another compound in haematite that makes the iron impure
sand / SiO2 (silicone dioxide)
what is the formula for the decomposition of calcium carbonate (limestone)
CaCO3(s) —> CaO(s) + CO2(g)
what is the formula for the reaction between calcium oxide and sand
CaO (s) + SiO2 (g) —> CaSiO3(l) (calcium silicate)
what is another word for molten calcium silicate
slag
how is slag removed?
it floats on the molten iron as it is less dense, and then removed separately from the bottom of the blast furnace
what three raw materials are needed for the extraction of iron
haematite, coke and limestone
