Graphene and fullerenes | Starter Quiz | Oak National Academy

What does the term 'allotrope' mean in chemistry?

• a type of chemical reaction

• a different physical form in which an element can exist

• a compound formed from two or more elements

• a mixture of two substances

Answer explanation

Allotropes are different physical forms in which an element can exist, like carbon in the form of diamond, graphite, and graphene.

Match the carbon allotrope to its primary use.

• coal

• fuel

• diamond

• lubricant

• graphite

• cutting tools

Answer explanation

Diamonds are primarily used in cutting tools due to their hardness, while graphite is used for lubrication due to its layered structure which allows layers to slide over each other. Coal is a mixture of carbon molecules, and is used as a fuel.

Which statement correctly describes the bonding in graphite?

• Each atom forms four single bonds with other atoms.

• Each atom forms double bonds with three other atoms.

• Each atom forms three single bonds with other atoms and has one free electron.

• Each carbon atom is bonded to four other atoms in a layered hexagonal structure.

Answer explanation

In graphite, each carbon atom forms three single bonds with other carbon atoms, creating layers of hexagonal rings, and has one free electron, contributing to its electrical conductivity.

Graphite is used as a lubricant because it is ...

• oily and wet.

• hard and durable.

• soft and slippery.

• sticky and thick.

Answer explanation

Graphite's soft and slippery nature, due to its layered structure, makes it an effective lubricant.

Why does graphite conduct electricity?

• it has free moving ions

• each carbon atom donates multiple electrons to a 'sea of electrons'

• it contains metallic bonds

• one electron from each carbon atom is delocalised across the structure

Answer explanation

Graphite conducts electricity because one electron from each carbon atom is delocalised, allowing it to move freely and carry an electric charge.

Graphite exists as a layered structure of hexagonal rings of carbon atoms, each bonded to three other atoms. Between the layers there are weak {{}} holding them together.

• forces of attraction

• intermolecular forces

• covalent bonds

• ionic bonds

• metallic bonds

Answer explanation

Graphite exists as a layered structure of hexagonal rings of carbon atoms, each bonded to three other atoms. Between the layers there are weak forces of attraction holding them together. As this is a giant covalent substance, there are no molecules.