C2 Material Choices

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C2 Material Choices
19/12/2013
OCR 21st Century
W Richards
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C2.1 Properties of Materials
Q. For each of the following materials describe
what properties the material needs to have and
why
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Properties of materials

• Plastic (polythene)
• Light
• Flexible
• Easily moulded

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Properties of materials

• Plastic (polystyrene)
• Light
• Rigid
• Good insulation

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Properties of materials

• Nylon
• Light
• Tough
• Waterproof

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Properties of materials

• Polyester
• Light
• Tough
• Waterproof

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Properties of materials

• Unvulcanised rubbers
• Low tensile strength
• Soft
• Flexible

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Properties of materials

• Vulcanised rubbers
• High tensile strength
• Hard
• Flexible

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C2.2 Crude Oil
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Using Different Materials
We use a variety of materials from a variety of
different places
These are all natural materials we can also
use synthetic (man-made) ones like plastics
these are often made from materials from within
the Earth like crude oil.
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Chemical formulae
The chemical formulae of a molecule or compound
is simply a way of showing the ratio of atoms in
it. For example
sodium chloride (NaCl)
potassium iodide (KI)
potassium nitrate (KNO3)
K
N
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Chemical formulae

• Try drawing these
• Water H2O
• Carbon dioxide CO2
• Calcium sulphate CaSO4
• Magnesium hydroxide Mg(OH)2

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Simple chemical reactions
Water
H2O
Magnesium sulphate
MgSO4
Notice that the number of atoms on each side of
the equation is the same!
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Hydrocarbons and crude oil
Crude oil is a mixture of HYDROCARBONS (compounds
made up of carbon and hydrogen). Some examples
These different lengths are called _______
and most of them are used as _____. Some are
used to make materials such as _______. Longer
chains have higher _____ points.
Words boiling, fractions, plastics, fuels
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Fractional distillation
Crude oil can be separated by fractional
distillation. The oil is evaporated and the
hydrocarbon chains of different lengths condense
at different temperatures
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Forces between molecules
Weak force of interaction here
Longer molecules stronger force of attraction,
leading to higher boiling points due to the
molecules needing more energy to pull them away
from each other.
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Polymers
Heres ethene. Ethene is called a MONOMER
because it is just one small molecule. We can
use ethene to make plastics
Step 1 Break the double bond
Step 2 Add the molecules together
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C2.3 Molecular Structure
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Uses of addition polymers
Poly(ethene)
Poly(propene)
Poly(chloroethene), PVC
Poly(styrene)
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Structure of Plastics
1) Some plastics have ____ intermolecular forces
between each molecule these have __ melting
points and can be ________ easily
2) Some plastics have _____ forces between each
molecule. These have ____ melting points and are
____.
Words high, low, strong, weak, stretched, rigid
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Forces between molecules
As weve already said, longer molecules have
stronger forces of attraction between them. This
tends to lead to longer chain plastics being

1. Stronger
2. Stiffer
3. Harder
4. More difficult to melt (i.e. higher melting point)

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Modifying Plastics
Polymers can be modified in a number of ways

• Increasing the chain length
• ...making it stronger

2) Crosslinking ...making it harder
3) Plasticizing ...making it softer and more
flexible
4) Packing more closely (a crystalline
polymer) ...making it stronger and more dense
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C2.4 Nanotechnology
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Nanotechnology
Task To find out what nanotechnology is and
what it is used for

1. What is nanotechnology?
2. Define the terms nanoparticle and nanocomposite
3. Gives some examples of its uses
4. Describe some of the future uses of this
   technology
5. Describe some of the ethical concerns over this
   technology

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Nanotechnology
Definition
Nanotechnology is a new branch of science that
refers to structures built from a few hundred
atoms and are 1-100nm big. They show different
properties to the same materials in bulk, partly
because they also have a large surface area to
volume ratio and their properties could lead to
new developments in computers, building materials
etc.
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How nanoparticles are formed
Nanoparticles can be formed by a number of
methods
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Two examples of nanotechnology
The Nano Carbon Pro tennis racket uses
nanoparticles to increase its strength.
Silver nanoparticles can be used to give fibres
antibacterial properties look at what they do
to e-coli bacteria
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Nanoscience and health
Nanoparticles are obviously very small and, as we
have said, have a large surface area to volume
ratio. This makes them useful but can also make
them dangerous. Nanoparticles could easily pass
through a cell membrane
Im going to die
How do these health concerns affect the
development of nanotechnology?