C2 - Allotropes Of Carbon

Question 1

What are allotropes?

Answer 1

Different structural forms of the same element in the physical state

(E.g diamond)

Question 2

Why is diamond very hard?

Answer 2

Diamond has a giant covalent structure, made up of carbon atoms that each form four covalent bonds

Question 3

How strong is diamonds covalent bonds?

Answer 3

They are strong covalent bonds which take a lot of energy to break

Question 4

What is diamonds melting point?

Answer 4

Very high

Question 5

Why does diamond not conduct any electricity?

Answer 5

As it has no free electrons or ions

Question 6

How many covalent bonds are there in graphite?

Answer 6

Three covalent bonds.This creates sheets of carbon atoms arranged in hexagons

Question 7

Are there any covalent bonds between the layers of graphite?

Answer 7

There are no covalent bonds between the layers - they are only held together weakly,so they are free to move over each other.This makes graphite soft and slippery,so it is ideal as a lubricating material

Question 8

Does graphite have a high or low melting point?

Answer 8

Graphite has a high melting point - the covalent bonds in the layers need loads of energy to break

Question 9

How many of carbons atoms are used for bonds?

Answer 9

Only three of each carbon’s four outer electrons are used in bonds,so each carbon atom has one electron that is delocalised (free) and can move.

Question 10

What can graphite conduct?

Answer 10

Electricity and thermal energy

Question 11

What is graphene made of(in terms of atoms)?

Answer 11

Graphene is a sheet of carbon atoms joined together in hexagons. The sheet is just one atom thick,making it a two-dimensional substance.

Question 12

What does the network of covalent bonds make graphene?

Answer 12

It makes it very strong and light,so it can be added to strong composite materials to improve their strength without adding much weight

Question 13

What type of electrons does graphene contain and what does it give the potential to be used in?

Answer 13

It contains delocalised electrons so it can conduct electricity through the whole structure. This means it has the potential to be used in electronics.

Question 14

What is the structure of fullerenes?

Answer 14

Fullerenes are molecules of carbon,shaped like closed tubes or hollow bells

Question 15

What was the first fullerene to be discovered?

Answer 15

Buckminsterfullerene was the first fullerene to be discovered,its got the molecular formula C60 and forms a hollow sphere

Question 16

What is fullerenes mainly made up of?

Answer 16

They’re mainly made up of carbon atoms arranged in hexagons, but can also contain pentagons (rings of five carbon atoms) or heptagons (ringe of seven carbon atoms).

Question 17

What can fullerenes be used to do?

Answer 17

Fullerenes can be used to ‘cage’ other molecules. The fullerene structure forms around another atom or molecule, which is then trapped inside. This could be used to deliver a drug into the body

Question 18

What do fullerenes have as a property which is beneficial?

Answer 18

Fullerenes have a huge surface area, so they could help make great industrial catalysts - individual catalyst molecules could be attached to the fullerenes. Fullerenes also make great lubricants.

Question 19

What can fullerenes form?

Answer 19

Fullerenes can form nanotubes - tiny carbon cylinders.

(The ratio between the length and the diameter of nanotubes is very high)

Question 20

Properties of nanotubes

Answer 20

• Can conduct both electricity and thermal energy (heat).
• High tensile strength(they don’t break when they are stretched)

Question 21

What is it called when technology uses very small particles?

Answer 21

Technology that uses very small particles such as nanotubes is called nanotechnology.Nanotubes can be used in electronics or to strengthen materials without adding much weight such as in tennis racket frames.