C2.2 Structure And Properties

Question 1

Ionic compounds consist of a giant structure of ions arranged in a ________
The attractive _______ between the ions act in all _________ and are very strong

Answer 1

Lattice
Forces
Directions

Question 2

It take a lot of ______ to break up a giant ionic lattice.
To separate to ions we have to ______ all the electrostatic forces of attractions
This means that they have ______ melting and boiling points

Answer 2

Force/energy
Break/overcome
High

Question 3

Describe current flow in a liquid and a solid.

Answer 3

In a liquid form the electrons can move around so the current can flow
In a solid the electrons can’t move around so the current stops

Question 4

Describe current in molten.

Answer 4

Once ions are molten or dissolved, they are free to move around
Therefore the ions can carry their electrical charge through the molten liquid
The positive ions go to the negative electrode and vice versa.

Question 5

Define intermolecular

Answer 5

These are forces acting between individual molecules

Question 6

Define intramolecular

Answer 6

The forces acting in a molecule holding the atoms together

Question 7

What are intermolecular forces?

Answer 7

Very weak

Question 8

Are intramolecular forces strong or weak?

Answer 8

Strong covalent bonds

Question 9

Describe the structure of diamond

Answer 9

Diamond is made of entirely carbon atoms. It’s made when carbon is out under extremely high pressure and temperature.
Diamond has a melting point of 3550 degrees Celsius and is the hardest naturally formed substance known. It’s a covalent bond but is an exception as its a giant structure

Question 10

Describe the structure of silicon dioxide

Answer 10

Used in production of glass
Has a melting point of 1600 degrees Celsius
Giant structure
High boiling point and melting point

Question 11

Describe the structure of graphite

Answer 11

Each carbon atom forms 3 covalent bonds. The extra electron that is not used to make a bond exists as a free (delocalised) electron. Just as in metals the delocalised electrons can carry the charge when a current is applied. Graphite exists as separate layers that can slide over each other (this is why it’s used in pencils)
Has a melting point of 3600 degrees c

Question 12

What are fullerenes?

Answer 12

Made by conjoined hexagonal carbon rings
It’s uses are:
Drug delivery
Inlubricants
Catalysts in reactions
To make nano tubes to reinforce structures

Question 13

What’s an allotrope?

Answer 13

Each of 2 or more different physical forms in which an element can exist
Eg. Diamond, graphite and charcoal

Question 14

Define an alloy

Answer 14

A mixture with at least one metal in it

Question 15

Why can we bend and shape metals?

Answer 15

The layers in an atom can slide past each other so you can bend them because they can move

Question 16

Why is steel strong?

Answer 16

It’s an alloy of iron and its stronger because there are no layers

Question 17

Why are alloys strong?

Answer 17

The contain atoms of different sizes which distorts the regular arrangements of atoms. This makes it more difficult for the layers to slide over each other, so alloys are harder than pure metals.

Question 18

What are smart alloys? Give examples

Answer 18

They remember their original shape so if they’re deformed they can return to their original shape usually by heating it.
Examples are braces, shape memory glasses and shape memory stent to keep a blocked blood vessel open.

Question 19

Define polymer

Answer 19

A long chain of monomers with double bonds

Question 20

What affects the properties of a polymer?

Answer 20

Length of chains
Type of monomers
Side links and branches
Temperature
Time take for polymer to cool down
Other chemicals present

Question 21

What are some properties of LD polyethene

Answer 21

Low density

Has branches formed at high pressure making them hard to pack together

Question 22

Give properties of HD polyethene

Answer 22

High density
Formed at lower pressure and using a catalyst at 50 degrees c
Polymer chains are straighter allowing them to pack closer together

Question 23

What’s a thermosoftening polymer?

Answer 23

The tangled web of polymer chains are relatively easy to separate
When heated molecules unwind and can slide past each other.
The material is flexible when it’s hot and can be shaped
When it cools it hardens
When the polymer is heated the weak intermolecular forces are broken so becomes soft

Question 24

What’s a thermosetting polymer?

Answer 24

Chains fixed together by strong covalent bonds - cross linking
When the polymer is heated the chains are linked to each other and can’t slide past each other
Once mounded the plastic will not soften and can’t be reshaped

Question 25

What’s vulcanisation?

Answer 25

A chemical process for converting natural rubber or related polymers into more durable materials from the addition of sulphur. These additives modify the polymer by forming cross links between individual polymer chains

Question 26

What is one nano metre?

Answer 26

1 billionth of a metre

Question 27

What is nanoscience?

Answer 27

Science on a very small scale

Question 28

What are benefits of nanoscience?

Answer 28

You can change one atom at a time in a structure and we will be able to create extremely small machines.
Nano medicine only targets s specific part of the body, you don’t have to travel through the whole body

Question 29

What are the risks with nanoscience?

Answer 29

Could be used badly for terrorism or spying
Nanoparticles are very reactive so if it gets into food or water it can be dangerous. This is because they have a huge surface area

Question 30

How big is an atom compared to a nanoparticle?

Answer 30

Smaller

Question 31

Nanoparticle strange in size from about _____ down to about ____

Answer 31

100nm to 1nm

Question 32

What are uses of nanoscience

Answer 32

Medicine
Machines
Brain implants
Catalysts because they're very reactive
Suntan lotion

Question 33

What are potential future creations for nanoscience?

Answer 33

It might be used for future diseases and restructuring atoms in our body to fight diseases or prevent tumours. Also it could make all clothing water repellent so nothing could get dirty.