Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Chemistry Ocr 21st Century Gcse > C2 > Flashcards

C2 Flashcards

You may prefer our related Brainscape-certified flashcards:
GCSE Geography - AQA flashcards AP® Chemistry flashcards GCSE Religious Studies - Edexcel Route B flashcards GCSE Religious Studies - Eduqas Route A flashcards GCSE Religious Studies - Edexcel Route A flashcards GCSE Religious Studies - Eduqas Route B flashcards Periodic Table flashcards Chemistry 101 flashcards Organic Chemistry 101 flashcards
1
Q

what is tensile strength?

A

the force needed to break a material when it is being stretched

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what is compressive strength?

A

the force needed to crush a material when it is being squeezed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

when can outliers be discarded?

A

if an error occured in the measurement

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

why have synthetic materials replaced many natural materials?

A

.some natural materials are in short supply
.they can be designed to give particular properties
.they are often cheaper and can be made in the quantity needed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what is crude oil made up of?

A

.hydrocarbons

.with chain molecules up to 100carbon atoms long

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

explain the stages of fractional distillation?

A

.the oil is heated up which turns it all into gas
.the distillation tower gets cooler when higher
.gas molecules condense into liquids when cool
.liquids with similar boiling points collect together called fractions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

where attractive forces exist?

A

between molecules in crude oil, holding them together

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

what is a polymer?

A

large molecule made by joining many smaller molecules called monomers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what is the process in which a polymer is made?

A

polymerisation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what does PET stand for and what does it make?

A

.polyethylene terephthalate

.used to make drinking bottles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

how can polymer chains be altered?

A

by replacing hydrogen atoms with other atoms or groups of atoms

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

describe low density polythene?

A

.long molecules with branches
.molecules are weak
.examples include plastic carrier bags

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

describe high density polythene?

A 
.long chains 
.no branches 
.molecules are closer
.long lasting
.used to make water pipes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what are the characteristics of high crystalline polymers?

A

.strong
.high melting points
.can be brittle (bad)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what are plasticisers used for?

A

.making polymers softer
.inserted into polymer chains
.weakens forces

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

what soften when heated and can be moulded into shape?

A

thermoplastics

17
Q

what plastics do not soften when heated, and contain cross links so don’t melt?

A

thermosetting plastics

18
Q

how can crystallinity increased?

A

.removing branches
.making chains flat as possible
.line them up neatly

19
Q

what process allows molecule chains to line up?

A

drawing polymers through a tiny hole when heated which increases crystallinity and forms a higher tensile strength fiber

20
Q

what do nanopartcles contain?

A

up to a thousand atoms

21
Q

where do nanopartcles occur?

A

.salt in sea Spray
.occur by accident
.can be designed in laboratories

22
Q

what is nanotechnology?

A

is the use and controlled of very small structures

23
Q

what is the scale of a nanometer?

A

a nanometer is one millionth of a millimeter

24
Q

what are nanometer partials effective catalysts?

A

they have a large surface area which provides more sites for chemical reactions to take place on

25
Q

what are sliver nanoparticals good at?

A

.killing bacteria

.can be used in socks, wound dressings, plastic

26
Q

what nanoparticals are used in sun screen?

A

titanium oxide nanoparticals which make it transparent

27
Q

what composite materials are made stronger by using nanoparticals?

A

.plastic sports equipment
.tennis balls
.rubber tyeres

28
Q

what composite materials are made stronger by using nanoparticals?

A

.plastic sports equipment
.tennis balls
.rubber tyeres

29
Q

what can graphene sheets be rolled into?

A

carbon nanotubes which are superstrenghth materials

30
Q

what damage can be done by silver nanopartcles?

A

.washed out of cloths into sewers
.in sewage bacteria can clean the water and the nanoparticals can kill the useful bacteria
.if realised into the environment it could kill microorganisms

31
Q

where do nanoparticals contain naturally?

A

.soot

.volcanic dust

32
Q

define risk?

A

as the change of an event occurring and yh3 consequences of it

Chemistry Ocr 21st Century Gcse (3 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions