C4 Separating Metals from Metal Oxides (pg 133) Flashcards
Lots of common metals, like iron and aluminium react with oxygen to form what?
Oxides.
This process is an example of oxidation.
These oxides are often the ores that the metals need to be extracted from.
A reaction that separates a metal from its oxide is called?
reduction reaction
What is meant by an ‘ore’?
An Ore is a type of rock that contains metal compounds
What is a formation of Metal Ore?
Oxidation = Gain of Oxygen
eg: Magnesium is oxidised to make magnesium oxide
2Mg + O2 »_space;> 2MgO
What is Extraction of Metal?
Reduction = Loss of Oxygen
E.G. copper oxide is reduced to copper
2CuO + C »_space;> 2Cu + CO2
Some metals can be extracted from their ores chemically by reduction using?
carbon.
In this reaction, the ore is reduced as oxygen is removed from it, and carbon gains oxygen so is oxidised.
for example:
2Fe2O3 + 3C »_space;»» 4Fe + 3CO2
Iron(III) oxide + Carbon »_space;»> Iron + carbon dioxide
How can you determine whether a metal can be extracted by reduction with carbon?
The position of the metal in the reactivity series determines whether it can be extracted by reduction with carbon.
Metals higher than carbon in the reactivity series have to be extracted using what?
using electrolysis (which is expensive)
metals higher than carbon are:
Potassium K
Sodium Na
Lithium Li
Calcium Magnesium Mg
Metals below carbon in the reactivity series can be extracted by reduction using what?
carbon.
for example, iron oxide is reduced in a blast furnace to make iron.
This is because carbon can only take the oxygen away from metals which are less reactive than carbon itself.
Metals below carbon in the reactivity series are:
Zinc Zn
Iron Fe
Copper Cu
Give an example of some metals that are so unreactive they are in the earth as the metal itself?
Gold - it is mined as its elemental form.
What is the difference between ‘Oxidation and Reduction - separating metals from metal oxides?
The terms oxidation and reduction can be defined in terms of the adding or removing oxygen to a compound. While this is not the most robust definition, it is the easiest to remember.
Oxidation is the gain of Oxygen
Reduction is the loss of Oxygen
Write a balanced equation for the reduction of lead oxide, PbO, by carbon, C? (2marks)
2PbO + C »_space;> 2Pb + CO2
(1 mark for the correct products, 1 mark for the correctly balanced equation)
A mining company tried to extract calcium from it’s ore by reduction with carbon. The process did not work. Explain why?
Carbon is less reactive than calcium and therefore will not reduce calcium oxide/Calcium is more reactive than carbon, so calcium oxide wont be reduced by cabon (1 mark)
