C2

Question 1

What does melting point mean?

Answer 1

The point at which something melts

Question 2

What does tensile strength mean?

Answer 2

The force required to break something when stretched

Question 3

What does compressive strength mean?

Answer 3

The force required to break something when squashed

Question 4

What is stiffness?

Answer 4

The opposite of flexible; it is the extent to which a material resists deformation on response to a force

Question 5

What is hardness?

Answer 5

Measure of how resistant a material is to being scratched by another material

Question 6

What is density?

Answer 6

The amount of mass contained per unit volume.

Question 7

What three categories can materials come under?

Answer 7

Metal, ceramics and polymers

Question 8

Give four examples of natural materials obtained from living things

Answer 8

Cotton, paper, silk and wool

Question 9

What does synthetic mean?

Answer 9

It means humans have made it

Question 10

Where do the raw materials used to make materials come from?

Answer 10

The Earth’s crust

Question 11

What is crude oil made from?

Answer 11

A mixture of different hydrocarbons of varying chain lenghts

Question 12

What is a hydrocarbon?

Answer 12

A molecule made from hydrogen and carbon atoms only

Question 13

A small amount of crude oil is used for chemical synthesis what is the rest used for ?

Answer 13

Fuel

Question 14

What is fractional distillation?

Answer 14

A process through which hydrocarbons are heated and separated into fractions of different boiling points in order to produce fuels , lubricants and raw materials for chemical synthesis

Question 15

How is the size of forces between the hydrocarbon linked to the size of the molecules?

Answer 15

The larger/longer the molecule, the greater the forces between the molecules

Question 16

Why do larger hydrocarbons have higher boiling points?

Answer 16

It takes more energy to overcome the intermolecular forces between them so that they can break out of a liquid form to form a gas

Question 17

What is polymerisation?

Answer 17

Monomers join together to make a long molecule called a ploymer

Question 18

Give an example of material that have replaced other materials because of their properties?

Answer 18

Nylon has replaced silk and cotton in clothing because of its strenght

Question 19

It is possible to produce a wide range of polymers; why is this a good thing?

Answer 19

It means that different polymers with different properties can be made for particular uses.

Question 20

What do the properties of a polymer depend upon?

Answer 20

How their molecules are arranged and held together

Question 21

What feature of a polymer molecule cause varying strength, stiffness, hardness and melting points?

Answer 21

The strength of the forces between the molecules in a polymer (intermolecular forces)

Question 22

How might increasing the chain of a polymer affect its properties?How does it do this?

Answer 22

Longer polymer chains make a material stronger and less flexible. This is because the polymer chains have stronger forces of attraction between the molecules

Question 23

How might increasing the cross-linking in a polymer affect its properties?

Answer 23

Cross-links make material tougher and less flexible. This because chemical bonds are used to link together the chains in the polymer

Question 24

How might using plasticisers in a polymer affect its properties?

Answer 24

Plasticisers make materials softer and more flexible. This is because the small plasticiser molecules are put between the molecule chain and weaken the forces between them. This means less energy is required to overcome the intermolecular forces in the molecule.

Question 25

How might increasing the crystallinity of a polymer affect its properties and how does it do this?

Answer 25

Crystalline structures are stronger and have higher melting points and density than non-crystalline polymers. This is because in crystalline structures the molecules are lined up regularly giving the material strong intermolecular forces that require lots of energy to seperate

Question 26

What is the size of nanoparticles?

Answer 26

1-100nm

Question 27

Name three ways in which nanoparticles can be made?

Answer 27

1. Naturally ie sea salt spray
2. Accidentally ie combustion of fuels
3. Designed in a lab ie silver nanoparticles in wound dressing

Question 28

Nanoparticles of a material show different properties compare to larger particles of the same material, give one reason for this?

Answer 28

They have a larger surface area to volume ratio

Question 29

Give two examples of how nanoparticles can be used to modify the properties of materials?

Answer 29

1. Silver antiparticles in fibres have antibacterial properties
2. adding nanoparticles to plastics for sports equipment in order to make them stronger

Question 30

Why is there concern about the use of nanoparticles?

Answer 30

The effects of nanoparticles are not yet known but they may have some negative effects on human health

Question 31

How might companies better inform consumers about nanoparticles?

Answer 31

Use warning/information labels on products.