2.9 Graphene and fullerenes
5 exam questions worth 9 marks. Write your answer, open the mark scheme, then give yourself the marks you earned. Your answers are saved on this device.
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Which is a molecule containing exactly 60 carbon atoms?
Choose one answer.
Correct Not quite: the answer is Buckminsterfullerene
Mark scheme
C
Model answer
C: buckminsterfullerene is C60.
Explain why graphene conducts electricity.
Mark scheme
- each carbon atom has one delocalised electron (1)
- which can move through the structure (1)
Model answer
Each carbon atom bonds to only three others, leaving one delocalised electron that can move across the sheet and carry charge.
Give two properties of carbon nanotubes that make them useful for reinforcing materials such as tennis rackets.
Mark scheme
any two from:
- high tensile strength / strong (1)
- light / low density (1)
- high length to diameter ratio (1)
Model answer
They have a very high tensile strength and are very light.
Explain why buckminsterfullerene has a much lower melting point than diamond.
Mark scheme
- C60 is made of (simple) molecules (1)
- weak intermolecular forces are overcome on melting (1)
- diamond requires many strong covalent bonds to be broken (1)
Model answer
Buckminsterfullerene is made of separate C60 molecules held by weak intermolecular forces, which need little energy to overcome. Melting diamond means breaking many strong covalent bonds.
Suggest why fullerenes could be used to deliver drugs in the body.
Mark scheme
- they are hollow / drug molecules can be placed inside the cage (1)
Model answer
Fullerenes are hollow cages, so drug molecules can be carried inside them.
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