Diamond and graphite

Question 1

Allotropes

Answer 1

It is the different physical forms of the same element

Question 2

List two allotropes of carbon

Answer 2

Diamond and graphite

Question 3

What do allotropes refer to only

Answer 3

Elements only

Question 4

How are the allotrophs diamond and graphite formed

Answer 4

diamond and graphite posses different structures and exist naturally in the earth and possibly formed via different conditions of temperature and pressure over the years. Many other elements also exhibit allotrophy.

Question 5

Describe the structure of a diamond

Answer 5

-In a diamond each C is connected to 4 other elements. Each C is connected to a tetrahedral arrangement (4) which continues to build up a diant structure
- Diamond has a large network of covalent bonds
- Diamond is not slippery (used to cut through metal)

Question 6

Describe the structure of graphite

Answer 6

-Each C is connected to 3 others. The atoms are arranged in flat hexagonal rings which form layers
- The layers are stacked on each other and held via weak van-der-waals forces
- Graphits has a large network of covalent bonds
- Each layer of graphite is called graphine
- when you write with a pencil with force, you break van-der-waals forces
- It is also used as a lubricant in factories

Question 7

Melting points of diamond and graphite

Answer 7

Very high melting and boiling points as in order to melt them a large network of covalent bonds would be broken

Question 8

Hardness of diamond

Answer 8

Due o the densly packed arrangement of atoms, it is one of the most hardest substances known to man

Question 9

Hardness of graphite

Answer 9

Atoms are not as densly packed, the weak forces between the layers enable them to slide over each other, resulting in a “soft crystal” which feels slippery, therefore it can act as a lubricant

Question 10

Conductivity of diamond

Answer 10

Diamond does not conduct electricity, the carbon atoms in diamond do not have any “free”electrons available to conduct an electric current

Question 11

Conductivity of graphite

Answer 11

Is a good conductor of electricity, the fourth electron of each carbon atom becomes delocalized allowing it to move about in the crystal. The moving electrons carry electricity through the crystal, therefore it is used as electrodes during electrolysis

Question 12

Shine of diamond

Answer 12

When light enters the structure it gets refracted many times which makes it shinier

Question 13

Shine of graphite

Answer 13

The structure of graphite is sheet like and weak bonds do not refract any light which makes it look dull