C2.2 - How Structure Influences Properties And Uses

Question 1

When a simple molecular substance melts or boils, which forces are broken?

Answer 1

The intermolecular forces.

Question 2

Why don’t simple molecular substances conduct electricity?

Answer 2

The molecules are not charged.

Question 3

What do ionic compounds have as a result of their strong bonds?

Answer 3

High melting and boiling points.

Question 4

When do ionic compounds conduct electricity and why?

Answer 4

When they are molten or dissolved in water, as the ions are free to move and carry the current.

Question 5

How many covalent bonds does each carbon atom form in diamond?

Answer 5

Four.

Question 6

How many covalent bonds does each carbon atom form in graphite?

Answer 6

Three.

Question 7

Which allotrope of carbon will conduct electricity and heat and why?

Answer 7

Graphite, because each carbon atom has a delocalised electron.

Question 8

What is silica a giant structure of?

Answer 8

Silicon and oxygen.

Question 9

Why is graphite soft and slippery?

Answer 9

Because the atoms are arranged in layers that are able to slide over each other.

Question 10

What are the intermolecular forces like between the layers in graphite?

Answer 10

Weak.

Question 11

In fullerenes, what shape are carbon atoms arranged in?

Answer 11

Hexagons.

Question 12

What are some uses for fullerenes? (4)

Answer 12

1. Drug delivery into the body.
2. Catalysts.
3. Lubricants.
4. In nanotubes for reinforcing materials.

Question 13

What is different in different types of fullerenes?

Answer 13

The number of carbon atoms.

Question 14

How many carbon atoms are in buckminsterfullerene molecules, and in what shape?

Answer 14

60 carbon atoms in a spherical molecule.

Question 15

What do allotropes of carbon form when they burn in oxygen?

Answer 15

Carbon dioxide.

Question 16

Why do metals conduct heat and electricity?

Answer 16

Because of their delocalised electrons.

Question 17

Why can metals be easily shaped?

Answer 17

The layers of atoms are able to slide over each other.

Question 18

What are alloys made from?

Answer 18

Two or more metals.

Question 19

Why are alloys less easily shaped than metals?

Answer 19

The different sized metal atoms distort the layers.

Question 20

What can shape memory alloys do?

Answer 20

Return to their original shape after being deformed.

Question 21

What shape memory alloy is used in braces?

Answer 21

Nitinol.

Question 22

Under what conditions are low density polymers made?

Answer 22

Heating ethene at about 200 degrees under high pressure.

Question 23

Under what conditions are high density polymers made?

Answer 23

Heating ethene at a low temperature and pressure with a catalyst.

Question 24

What are the properties of thermosoftening polymers? (5)

Answer 24

1. Made up of individual tangled chains of polymers.
2. Weak intermolecular forces.
3. The chains can slide over each other.
4. Low melting points.
5. Easily re-shaped.

Question 25

What are the properties of thermosetting polymers? (4)

Answer 25

1. Strong intermolecular forces.
2. Polymer chains called crosslinks hold the chains together.
3. A solid structure.
4. Strong/rigid/hard.

Question 26

What size are the structures referred to in nanoscience?

Answer 26

Between 1 and 100 nanometres.

Question 27

What is the surface area to volume ratio in nanoparticles like?

Answer 27

High.

Question 28

How are nanoparticles used in the cosmetic industry?

Answer 28

In sun tan creams and deodorants.

Question 29

What are the uses of nanoparticles? (5)

Answer 29

1. Computers.
2. Catalysts.
3. Cosmetics.
4. Construction.
5. Coatings.

Question 30

What are the properties of substances that consist of simple molecules?

Answer 30

Low melting and boiling points.