| Method |
Precise Learning Objective |
Linked |
Question / Activity
(Designed for maximum working out) |
Stepping Stones |
Pitstop Check
(Thinking Map) |
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Metals can be extracted from molten compounds using electrolysis. Electrolysis is used if the metal is too reactive to be extracted by reduction with carbon or if the metal reacts with carbon. |
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When is electrolysis used to extract metals from their ores? Demo:
electrolysis of molten lead bromide
http://www.rsc.org/learn-chemistry/resource/res00001725/electrolysing-molten-lead-ii-bromide?cmpid=CMP00005239 |
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Large amounts of energy are used in the extraction process to melt the compounds and to produce the electrical current. |
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What is the main drawback of using electrolysis to extract metals? |
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Aluminium is manufactured by the electrolysis of a molten mixture of aluminium oxide and cryolite using carbon as the positive electrode (anode). |
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How is aluminium extracted from its metal ore (aluminium oxide)? |
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Students should be able to explain why a mixture is used as the electrolyte |
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Why is a mixture used as the electrolyte in electrolysis? |
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Students should be able to explain why the positive electrode must be continually replaced. |
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Why does the positive electrode (the anode) need to be replaced regularly? |
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(HT only) students should be able to write half equations for the reactions occurring at the electrodes during electrolysis, and may be required to complete and balance supplied half equations for this process . (MS) |
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(HT)What are the missing reactants and products of the half equation shown below:
Mg2 ___--> _____ |
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