C2.2 Structure and Properties Flashcards Preview

GCSE Chemistry AQA > C2.2 Structure and Properties > Flashcards

Flashcards in C2.2 Structure and Properties Deck (22):
1

Explain why NaCl is a solid at room temperature

It has a giant ionic lattice
It is held together by ionic bonds which are very strong
Therefore it has a high melting point

2

Explain why oxygen is a gas at room temperature

It has a simple molecular structure
It is held together by weak intermolecular forces
Therefore it has a low melting point

3

Explain why iron is a solid at room temperature

It has a giant metallic structure
It is held together by strong metallic bonds
Therefore it has a high melting point

4

Explain why iron conducts electricity as a solid and liquid

It has delocalised electrons which are free to move throughout the metal structure

5

Explain why graphite conducts electricity

Each carbon has only 3 bonds.
This leaves one delocalised electron
Which is free to move

6

Explain why diamond doesn't conduct electricity

Each carbon has 4 bonds.
It has no free electrons

7

Explain why sodium chloride doesn't conduct electricity as a solid

The ions can't move

8

Explain why sodium chloride conducts electricity when dissolved

The ions are free to move

9

Explain why carbon dioxide doesn't conduct electricity

Its electrons aren't free to move

10

Explain why molten magnesium chloride can conduct electricity

The ions are free to move

11

Explain why ammonia is a gas at room temperature

It is a simple molecular substance
Its held together by weak intermolecular forces
Therefore it has a low melting point

12

Explain why methane is a gas at room temperature

It is a simple molecular substance
It is held together by weak intermolecular forces
Therefore it has a low melting point

13

Explain why silicon dioxide has an unusually high melting point

It has a giant covalent structure
It has strong covalent bonds
Which require a lot of energy to break

14

Explain why graphite has a very high melting point

It has a giant covalent structure
which is held together by strong covalent bonds
which require a lot of energy to break

15

What property makes diamond useful for sharpening knives

It is very hard

16

Explain why diamond is so hard

It is arranged in a giant lattice
Each carbon has 4 bonds
The lattice is rigid

17

Explain why thermosetting polymers have high melting points

They have crosslinks between the chains
made with covalent bonds
which are strong

18

Explain why high density polyethene has a higher melting point than low density polyethene

High density polyethene has a crystalline structure and strong forces between the polymer chains

19

What is a nanoparticle

a particle between 1nm and 100nm in size

20

Why do nanoparticles have different properties?

Because they have a much bigger surface area

21

What are the risks of nanoparticles?

Their large surface area makes them very reactive/explosive (nano aluminium)
Nanoparticles are easily absorbed by the lungs and there is little research into the long term health risks.

22

What conditions can be changed to make High Density Polyethene rather than Low Density Poly Ethene?

Pressure
Temperature