Specification Point 1.38:
Explain the properties of fullerenes including C60 and graphene in terms of their structures and bonding.
- Fullerenes are a group of carbon allotropes which consist of molecules made only of carbon and which form hollow tubes or spheres.
- Fullerenes can be used to trap other molecules by forming around the target molecule and capturing it, making them useful for targeted drug delivery systems.
- They also have a huge surface area and are useful for trapping catalyst molecules onto their surfaces making them accessible to the reactants so catalysis can take place.
- Two important fullerenes are graphene and Buckminsterfullerene.
- C60 is otherwise known as Buckminsterfullerene, commonly referred to as “Buckyballs”.
- The carbon atoms are joined together forming 20 hexagons and 12 pentagons which produce a hollow sphere.
Diagram showing the structure of the hollow sphere of Buckminsterfullerene
- Graphene consists of a single layer of graphite joined together in hexagons, hence it is essentially a 2D molecule since it is only one atom thick.
- It is extremely strong and has free electrons which are free to move along its surface.
- These properties make it useful in electronics and in making composite materials.
Diagram showing the 2-dimensional sheet of graphene
- Graphene can also be rolled into a cylinder to produce a nanotube.
- These have high tensile strength and are resistant to breaking or stretching.
- As in graphene, nanotubes can also conduct which makes them useful in composites and specialised materials, electronics and nanotechnology.
Diagram showing a nanotube produced from a rolled sheet of graphene
Specification Point 1.39:
Describe, using poly(ethene) as the example, that simple polymers consist of large molecules containing chains of carbon atoms.
- Polymers are very large molecules which are built up by linking together 50 or more smaller molecules called monomers.
- Each repeat unit is connected to the adjacent units via covalent bonds.
- Some polymers called homopolymers contain just one type of monomer unit.
- Examples of these include polythene and polychloroethene, commonly known as PVC.
- Others contain two or more different types of monomer units which are called copolymers which have interesting and useful properties.
- Examples of these include ABS, a copolymer used in producing water pipes and musical instruments.
- Polythene is a very common type of polymer which is formed from the addition of many ethene monomers together.
- The intermolecular forces between the molecules in a polymer tend to be strong hence many of these substances are solid at room temperature.
Polymerisation of ethene monomers produces polythene. The small n signifies that there is a large number of repeat units
Edexcel GCSE Chemistry Notes
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Morgan’s passion for the Periodic Table begun on his 10th birthday when he received his first Chemistry set. After studying the subject at university he went on to become a fully fledged Chemistry teacher, and now works in an international school in Madrid! In his spare time he helps create our fantastic resources to help you ace your exams.
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