Separation of mixtures
3 marks · EasyA student has a mixture of iron filings and sulfur powder. They want to separate the two substances.
State one physical property that can be used to separate iron filings from sulfur powder.
Describe the separation technique they should use.
Explain why this technique does not work for separating iron that has chemically reacted with sulfur.
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(a) Magnetism · must show magnetism
(b) Use a magnet to attract and remove the iron filings from the mixture. · must show magnet
(c) Because the iron has reacted with sulfur to form iron sulfide, which is a compound and cannot be separated by physical means such as magnetism. · must show compound cannot be separated by physical means
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Marking points
B1 (a) · 1 mark · States magnetism as the property used.
B1 (b) · 1 mark · Describes using a magnet to separate the iron filings.
B1 (c) · 1 mark · Explains that compounds cannot be separated by physical means.
Worked solution
a) Magnetism can be used because iron is magnetic but sulfur is not.
b) Use a magnet to attract out the iron filings, leaving sulfur behind.
c) After iron and sulfur react, they form a new substance (iron sulfide) which cannot be separated by physical methods like magnetism.