1.4 Types of substances

Question 1

Fullerenes

Answer 1

Fullerenes are a group of carbon allotropes which consist of molecules that 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 easily accessible to reactants so catalysis can take place.
Some fullerenes are excellent lubricants and are starting to be used in many industrial processes.
The first fullerene to be discovered was buckminsterfullerene.
In this fullerene, 60 carbon atoms are joined together forming 20 hexagons and 12 pentagons which produce a hollow sphere.

Question 2

Graphene

Answer 2

Graphene consists of a single layer of graphite which is a sheet of carbon atoms covalently bonded forming a continuous hexagonal layer.
It is essentially a 2D molecule since it is only one atom thick.
It has very unusual properties make it useful in fabricating composite materials and in electronics.

Question 3

Properties of graphene

Answer 3

Strength: It is very strong due to its unbroken pattern and the strong covalent bonds between the carbon atoms.
Conductivity: It has free electrons which can move along its surface allowing it to conduct electricity. It is also an excellent conductor of heat.
Flexibility: Those strong bonds between graphene’s carbon atoms are also very flexible. They can be twisted, pulled and curved to a certain extent without breaking, which means graphene is bendable and stretchable
Transparent: Graphene absorbs 2.3% of the visible light that hits it, which means you can see through it without having to deal with any glare.
This gives it the potential to be used for making computer screens of the future.

Question 4

Nanotubes

Answer 4

Nanotubes are fullerenes which are tiny carbon cylinders. The ratio between the length and the diameter of nanotubes is very high. They’re good conductors of heat and electricity.

Question 5

Polymers

Answer 5

They are molecules made up of long chains of covalently bonded carbon atoms. they are formed when lots of small molecules called monomers are joined together e.g. polyethene.

Question 6

Poly(ethene)

Answer 6

Poly(ethene) 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.