12. Redox - Reduction
Outcomes:
> Be able to identify a species that is being reduced in a chemical reaction.
> Be able to explain why reduction reactions are important in the extraction of metals from ores.
While oxidation was traditionally seen as the addition of oxygen to a chemical, reduction was seen as the process of removing oxygen from a chemical.
Demonstration:
Watch the reduction of copper(II) oxide using butane.
image: www.rsc.org
We now define reduction as the gain of electrons:
Reduction
Is
Gain
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Lead (II) oxide can be reduced by reacting it with carbon. This reaction occurs because carbon is higher in the activity (previously reactivity) series than lead.
lead oxide + carbon --> lead + carbon dioxide
2PbO(s) + C(s) --> 2Pb(s) + CO2(g)
> What is the change in oxidation state for the lead in this reaction?
Looking at this reaction, the lead loses its oxygen, we say that lead oxide is reduced.
The carbon gains oxygen, we say that carbon is oxidised.
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Iron is extracted from iron oxide using carbon monoxide in the blast furnace.
iron oxide + carbon monoxide --> iron + carbon dioxide
Fe2O3(s) + 3CO(g) --> 2Fe(s) + 3CO2(g)
> Which species is reduced, which species is oxidised?
Formative Assessment Task - Poster
Produce a poster that shows and explains how redox chemistry is used to extract pure iron metal from iron ore using the blast furnace.
Your poster should include:
- a labelled diagram of a blast furnace
- balanced equations for all the reactions involved
- an explanation of which species are oxidised and which are reduced
- a brief summary of the environmental impacts of producing iron using the blast furnace
- an outline of how science can be used to reduce these environmental impacts.
Your poster should fit onto one side of an A3 piece of paper, it can be completed by hand or on computer.
Next Lesson: 11. Electrolysis
