Ocr Gcse Chemisty- C2

Front 1

How can solid materials differ (in terms of properties)?

Back 1

They can differ in melting points

strength (tension or compression)

stiffness

hardness

density

Front 2

Meaning of strong ?

Back 2

if the material needs a large force to break it

Front 3

Meaning of tensile strength ?

Back 3

How much of a pull force is needed to break it

Front 4

Meaning of compressive strength ?

Back 4

how much push force is needed to break it ?

Front 5

Meaning of stiff ?

Back 5

Opposite to flexible, difficult to bend or stretch

Front 6

meaning of hard ?

Back 6

difficult to scratch

Front 7

Properties of plastics ? (5)

Back 7

hard

strong

stiff

fairly low density

mouldable

Front 8

Properties of rubber ? (4)

Back 8

strong

soft

flexible

mouldable

Front 9

what are material we use?

Back 9

Chemicals or mixtures of chemicals,

these include

- metals

-ceramics

-polymers

Front 10

Materials be made or obtained from ....

Back 10

living things

Front 11

Name Natural polymers ? (4)

Back 11

cotton

paper

silk

wool

Front 12

Name Synthetic polymers ? (5)

Back 12

Polythene

Polypropylene

PVC

Polyester

PET

Front 13

What can raw materials from the earths crust be used to make ?

Back 13

Synthetic materials

Front 14

During a chemical reaction the number of atoms at the start of the reaction is ....

Back 14

the same as the number of atoms at the end of the reaction

Front 15

What does crude oil mainly consist of ?

Back 15

hydrocarbons

Front 16

What is a hydrocarbon ?

Back 16

A chain molecule of varying lengths made from carbon and hydrogen atoms only

Front 17

A small percentage of crude oil is used for .... ?

Back 17

chemical synthesis and most is used as fuels

Front 18

What does the petrochemical industry do ?

Back 18

it refines crude oil by fractional distillation

Front 19

How is crude oil separated ?

Back 19

by Fractional Distillation

Front 20

How does fractional distillation work ?

Back 20

1. hydrocarbons are separated into fractions of different boiling points

2. to produce fuels

3. to produce lubricants

4. and raw materials for chemical synthesis

Front 21

Relate the size of the forces between hydrocarbon molecules to the size of the molecules ?

Back 21

The longer the size of the molecule the stronger the force so the higher the boiling point (thick and sticky)

Front 22

Boiling point of short chain hydrocarbon molecules ?

Back 22

low boiling points - often gases

Front 23

Boiling point of long chain hydrocarbon molecules ?

Back 23

high boiling points- (thick and sticky)

Front 24

Name the two types of important bonds in crude oil (hydrocarbon) and explain them?

Back 24

1. strong covalent bond- between the hydrogen and carbon atoms (within each hydrocarbon)

2. intermolecular forces- attraction between different hydrocarbon molecules in the mixture

Front 25

What happens when crude oil when it is heated ?

Back 25

The molecules are supplied with extra energy, eventually the molecules can gain enough energy to overcome their intermolecular forces, it then turns into a gas

Front 26

What is stronger...the covalent bonds holding each molecule together or the intermolecular forces ?

Back 26

the covalent bonds holding each molecule together are much stronger than the intermolecular forces.

Front 27

Describe the intermolecular forces in small hydrocarbons (crude oil) ?

Back 27

the intermolecular forces break more easily in small molecules than in bigger molecules. The intermolecular attraction is weaker in small molecules

Front 28

what kind of boiling points do big molecules have ?

Back 28

they have high boiling points- more energy is needed for them to break out of a liquid and form a gas

Front 29

What are small molecules called ?

Back 29

Monomers

Front 30

What happens during polymerisation ?

Back 30

small molecules called monomers join together to make very long molecules called polymers

Front 31

Name examples of materials, that because of their superior properties, have replaced materials used in the past ?

Back 31

cotton, wool, silk ---> nylon and polyester

wood-----> PVC

Front 32

What do the properties of polymers depend on ?

Back 32

how their molecules are arranged and held together

Front 33

What modifications in polymers have produced changes to their properties ? (4)

Back 33

1. increased chain length

2. cross - linking

3. the use of plasticisers

4. increased crystallinity

Front 34

cross links properties (5)

Back 34

1. less flexible

2. stronger

3. harder

4. higher melting point

5. stops rubber molecules uncoiling and sliding past each other

Front 35

cross links

Back 35

Front 36

Plasticisers- properties (5)

Back 36

1. flexible

2. softer

3. low melting point

4. oily liquid

5. Makes PVC softer

Front 37

Plasticiser

Back 37

Front 38

Branching chain properties (6)

Back 38

1. stretchy

2. elastic

3. rustle and noisy

4. plastic bags

5. line up irregularly

6. LDPE

Front 39

Branching chain

Back 39

Front 40

Crystalline polymer properties (5)

Back 40

1. stronger

2. denser

3. arranged in neat lines

4. plastic milk bottles

5. HDPE

Front 41

Crystalline polymer

Back 41

Front 42

What does nanotechnology involve ?

Back 42

it involves structures that are about the same size as some molecules

Front 43

what is nanotechnology ?

Back 43

it is the use and control of structures that are very small (1-100nm)

Front 44

how can nanoparticles occur ?

Back 44

They can occur

-naturally - seaspray

-by accident- smallest particles from combustion of fuels

-by design

Front 45

What do nanoparticles of a material show ? (properties) and give the reason

Back 45

they show different properties compared to larger particles of the same material. A reason of this is much larger surface area of the nanoparticles compared to their volume

Front 46

What can nanoparticles be used for ?

Back 46

They can be used to modify the properties of materials

Front 47

Examples of nanoparticles being used to modify the properties of materials ?

Back 47

1. the use of silver nanoparticles to give fibres antibacterial properties

2. adding nanoparticles to plastics for sport equipment to make them stronger (tennis rackets)

Front 48

Risks of nanotechnology ?

Back 48

1. Nobody knows the long term effects

2. large surface area to their volume, so they can react very quickly, this could speed up reactions such as illnesses

3. particles are so small they may be able to enter the brain from the bloodstream

4. nanoparticle have different properties, they may have different effects on plants/ animals.