C2

?
What is every material made up of?
Chemicals, either individual or mixtures.
1 of 31
What is a mixture?
Contains different substances that aren't chemically bonded together.
2 of 31
What materials occur naturally?
Materials from plants (wood/paper, cotton), materials from animals (wool, silk, leather)
3 of 31
What materials are synthetic?
Rubber (can control properties), Clothes, i.e nylon/polyester, paints are mixtures on man-made chemicals.
4 of 31
Where do the raw materials used to make synthetic materials come from?
Earth's crust, e.g. aluminium/chronium are used in metal alloys.
5 of 31
What is a meting point?
The temperature where the solid material turns to liquid..
6 of 31
What is strength?
How good a material is at resisting a force.
7 of 31
What is tensile/tension strength?
How much a material can resist a pulling force. Ropes/cables need a high tensile strength or they'd snap/
8 of 31
What is compressive strength?
How much a material can resist a pushing force. Building materials need a good compressive strength or they'd be squashed.
9 of 31
What is stiffness?
A atiff material is good at not bending when a force is applied to it. Steel is stiff where as rubber isn't.
10 of 31
What is hardness?
How difficult a material is to cut into. Diamond is the hardest material.
11 of 31
What is density?
A material's mass per unit volume. Objects less dense than water float.
12 of 31
What is effectiveness?
How good a material is at the job it's supposed to do. This depends on the materials it's made from
13 of 31
What is the difference between petrol and diesel?
Petrol contains hydrocarbons with around 8 carbons. Diesel contains slightly longer chain hydrocarbons.
14 of 31
What happens as the length of the carbon chain changes?
The properties of the hydrocarbon changes. Short-chain molecules have lower boiling points - often gases. Long-chain molecules have high boiling points and can be viscous.
15 of 31
What are the two types of bond in crude oil?
Strong covalent bonds (between the carbons and hydrogens within each hydrocarbon molecule) and Intermolecular forcees of attraction (between different hydrocarbon molecules in the mixture)
16 of 31
How is crude oil separated?
By fractional distillation.
17 of 31
How does fractional distillation work?
Hydrocarbons are separated into groups (fraction) with different boiling points. Each fraction has hydrocarbons with similar chain lengths.
18 of 31
What does the uses of hydrocarbons depend on?
The length of it's molecule chains.
19 of 31
What are some of the various uses of crude oil?
Petrochemical industry (fuels/lubricants), to produce raw materials that can be used to make synthetic chemicals.
20 of 31
What is polymerisation?
Under high pressure many small molecules polymerise to form long chains called polymers.
21 of 31
How has polymers been used as alternatives to traditional materials?
Synthetic fibres (nylon/polyester) replace cotton/wool/silk. They are lighter, more durable, water-resistant and often cheaper. They aren't breathable. Rigid PVC has replaced wood for window frames. It's weather-resistant, strong, durable.
22 of 31
What two things does a polymer's properties depend on?
How the molecules are arranged (packed close = high density) and how they're held together (weak forces = low melting point)
23 of 31
What are crosslinks?
Chemical bonds between the polymer chains.
24 of 31
What four ways can polymers be chemically modified?
Increase chain length (longer = stiffer, high melting point), add cross-linking agents (stiffer, stronger), add plasticisers (get in between polymer chains and reduce forces = softer), more crystalline (straight chains, no branches = high density)
25 of 31
What are nanoparticles?
Tiny particles 1-100 nanometres across.
26 of 31
What is nanotechnology?
The branch of technology dealing with the making and use of nanoparticles.It involves understanding how to control matter on a very small scale.
27 of 31
What nanoscale materials occur naturally/ are produced by accident?
Seaspray (nanoscale salt particles present in the atmosphere), combustion (nanoscale soot particles are produced)
28 of 31
What are two examples of nanoparticles being added to materials to give them different properties?
Plastics in sports equipment (stronger, more durable, don't add weight),surgical masks (silver nanoparticles added to polymer fibres to give antibacterial properties).
29 of 31
Why are nanoparticles useful?
They are much smaller than larger particles of the same material. This means they have a larger surface area-to-volume ratio which is what gives them different properties.
30 of 31
What is the problem with nanoparticles?
The way they affect the body isn't understood so should be tested thoroughly. The long-term impacts on health are unknown. Many belive products containing nanoparticles should be clearly labelled.
31 of 31

Other cards in this set

Card 2

Front

What is a mixture?

Back

Contains different substances that aren't chemically bonded together.

Card 3

Front

What materials occur naturally?

Back

Preview of the front of card 3

Card 4

Front

What materials are synthetic?

Back

Preview of the front of card 4

Card 5

Front

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

Back

Preview of the front of card 5
View more cards

Comments

No comments have yet been made

Similar Chemistry resources:

C6
See all Chemistry resources »See all Atoms resources »