The origin of crude oil
3 marks · NormalExplain why crude oil can be separated by physical methods, and not by chemical methods.
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Crude oil is a mixture, not a compound, so its components (hydrocarbons) are not chemically joined and can be separated using physical methods like distillation.
Also accept: The substances in a mixture keep their own properties and can be separated physically.
Common mistakes: Calling crude oil a compound; Saying it must be separated chemically
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Marking points
M1 · 1 mark · States that crude oil is a mixture, not a compound.
M2 · 1 mark · Mentions the components are not chemically bonded.
A1 · 1 mark · Describes or names a physical method (such as distillation) as suitable.
Worked solution
Crude oil is a mixture of different hydrocarbons, not a compound.
The components of a mixture are not chemically bonded, so they retain their individual properties.
They can be separated by physical methods, such as distillation.