C2.2 - How Structure Influences Properties

Question 1

What states of matter can simple molecules be?

Answer 1

Solids, Liquids or Gases., that have relatively low melting/boiling points.

Question 2

Why do these simple molecules have low melting/boiling points?

Answer 2

They only have weak intermolecular fores. When these forces are over come, the substance melts/boils.

Question 3

Why do substances which consist of simple molecules not conduct electricity?

Answer 3

They have no overall electric charge.

Question 4

What is an ionic compound usually called?

Answer 4

A Giant Ionic Lattice.

Question 5

How are the ionic bonds formed?

Answer 5

There are strong electrostatic forces in all directions between oppositely charged ions.

Question 6

Why do these compound have high melting/boiling points?

Answer 6

Large amounts of energy is needed to break the many strong bonds.

Question 7

In what state can ionic compounds conduct electricity?

Answer 7

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

Question 8

What are giant covalent structures usually called?

Answer 8

Macromolecules.

Question 9

How are atoms in giant covalent structures linked?

Answer 9

By strong covalent bonds, so they also have very high melting/boiling points.

Question 10

Describe the structure of Diamond:

Answer 10

• Made up entirey of Carbon, covalently bonded
• Each Carbon atom has 4 bonds
• Giant Covalent Structure
• Very hard, because all possible bonds are achieved, and are also strong.

Question 11

Describe the structure of Graphite:

Answer 11

• Made up entirely of Carbon, covalently bonded.
• Each Carbon atoms bonds to three others.
• Arranged in layers
• Layers are free to slide over each other, because there are no covalent bonds between them.
• Graphite is soft and slippery, due to the weak intermolecular forces between layers.

Question 12

Does Graphite conduct electricity?

Answer 12

Yes, because one electron from each carbon atom is delocalised, these electrons allow graphite to conduct electricity and also heat.

Question 13

What can Fullerenes be used for?

Answer 13

• Drug delivery into the body
• Lubricants
• As Catalysts
• In nanotubes, for reinforcing material eg. in tennis rackets

Question 14

How is graphite similar to metals?

Answer 14

It has delocalised electrons.

Question 15

What is the structure of Fullerenes based on?

Answer 15

Hexagonal rings of carbon atoms.

Question 16

Why do metals conduct heat and electricity?

Answer 16

They have delocalised electrons in their structure.

Question 17

What are alloys made of?

Answer 17

Two or more different metals.

Question 18

Why are alloys much harder than metals?

Answer 18

The different sized atoms of the metals distort the layers in the structure of the alloy, making it more difficult for them to slide over each other, making alloys harder than pure metals.

Question 19

What do the properties of a polymers depend on?

Answer 19

What they are made from and the conditions under
which they are made. For example, low density (LD) and high density (HD) poly(ethene) are produced using different catalysts and reaction conditions.

Question 20

What do thermosoftening polymers consist of?

Answer 20

Many individual, tangled polymer chains.

Question 21

What do thermosetting polymers consist of?

Answer 21

Polymer chains with cross-links between them so that they do not melt when they are heated.

Question 22

What is Nanoscience?

Answer 22

It refers to structures that are 1–100 nm in size, of the order of a few hundred atoms.

Question 23

What can Nanoparticles be used for?

Answer 23

Due to the high surface area to volume ratio, they may lead to the development of

• new computers
• new catalysts
• new coatings
• highly selective sensors
• stronger and lighter construction materials
• new cosmetics such as sun tan creams and deodorants.