Extracting metals Cambridge IGCSE Combined Science revision
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In plain words
Most metals are found in rocks, locked up in compounds called ores. Getting the metal out means taking the oxygen away. For some metals carbon can do that cheaply. The most reactive metals hold on too tightly, and have to be torn out with electricity.
Three things to know
- How a metal is extracted depends on its place in the reactivity series. Metals below carbon (zinc, iron) are extracted by heating their oxides with carbon.
- Metals above carbon (aluminium, sodium) are extracted by electrolysis, which costs much more because of the electricity used.
- Very unreactive metals (gold) are found as the metal itself. Removing oxygen from an ore is reduction.
Tips and tricks
- Above carbon: electrolysis. Below carbon: heat with carbon. Know where carbon sits in the series.
- Electrolysis is expensive "because it uses a large amount of electricity". That's the reason to give.
It lands in your notebook with its questions as flashcards.
Extracting metals: 5 questions and answers
These are the quiz’s questions. Do the quiz first, then come back here for the ones that got you.
How are metals below carbon in the reactivity series usually extracted?
Carbon is more reactive, so it removes the oxygen.
How is aluminium extracted?
It is more reactive than carbon.
Why is gold found as the metal itself?
It does not react with oxygen or water.
What is the removal of oxygen from a metal oxide called?
Reduction is the loss of oxygen.
Why is electrolysis an expensive way to extract a metal?
Large amounts of electrical energy are needed.
Quiz
5 questions
Tap an answer and you’ll see straight away whether it’s right, and why.
Worksheet
4 questions, 7 marks. Write your answers on paper, then check them.
Extracting metals
Cambridge IGCSE Combined Science 0653 · 7 marks · papermunch.org
Name ______________________________ Date ______________
Explain why iron can be extracted by heating its oxide with carbon but aluminium cannot.[2]
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Carbon is more reactive than iron, so it can take the oxygen from iron oxide. Aluminium is more reactive than carbon.
State the method used to extract aluminium from its ore.[1]
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Electrolysis.
Explain why gold is found in the ground as the metal, not as a compound.[2]
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It is very unreactive, so it does not combine with oxygen or other elements.
Iron(III) oxide is heated with carbon. Name the type of reaction that turns the iron(III) oxide into iron, and explain your answer.[2]
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Reduction: the iron(III) oxide loses oxygen.
Answers: Extracting metals
- 1. Carbon is more reactive than iron, so it can take the oxygen from iron oxide. Aluminium is more reactive than carbon.
- 2. Electrolysis.
- 3. It is very unreactive, so it does not combine with oxygen or other elements.
- 4. Reduction: the iron(III) oxide loses oxygen.