C4 Flashcards

1
Q

What are plastics made up of?

A

Polymers

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2
Q

What are polymers?

A

Molecules formed when monomers are joined together.

To make polymers, high pressure and a catalyst are required

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3
Q

What are addition polymers made up of?

A

Made up of monomers which have a carbon-carbon double bond functional group.

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4
Q

What is condensation polymerisation?

A

2 different monomers with different functional groups which react together, forming bonds.

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5
Q

What are polymers held together by?

A

In polymers, all the atoms are held together by strong covalent bonds.
There are intermolecular forces between the chains

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6
Q

What are the properties of Low density polyethene?

A

Lots of space between polymer chains, so forces are weak

-This makes it flexible so it is used for plastic bags

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7
Q

What are the properties of High density polyethene?

A

Chains have strong forces of attraction, which makes it stronger and is used for watertanks.

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8
Q

What do polymers which only contain intermolecular forces have?

A

Contain individual tangled chains

  • can slide over each other
  • the forces between the chains can be overcome, so the polymers can be melted.
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9
Q

What are the properties of polymers with cross-links?

A

The chains are held together strongly.

  • polymers don’t soften when heated
  • strong, hard and stiff.
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10
Q

What are giant covalent structures?

A

Atoms bonded by strong covalent bonds
High melting and boiling points
Do not conduct

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11
Q

What is diamons?

A

Forms 4, strong covalent bonds

  • very hard
  • High melting point
  • Doesn’t conduct as it has no free electrons
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12
Q

What is graphite?

A

Only forms 33 covallent bonds, creating sheets of carbon atoms.

  • layers are held together by weak intermolecular forces so can be rubbed off each other.
  • high melting point as covalent bonds are hard to break
  • graphite can conduct as there are free eletrons
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13
Q

What is graphene?

A

A single sheet of graphine

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14
Q

What is an example of ionic bonding?

A

NaCl

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15
Q

What is an example of simple molecular bonding?

A

CO2

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16
Q

What is an example of metallic bonding?

A

Iron

17
Q

What is an example of a polymer?

A

Polyethene

18
Q

What is an example of giant covalent structure?

A

Diamond

19
Q

What are the different bulk properties of materials?

A
  • Melting point
  • Strength
  • Stiffness
  • Hardness
  • Brittleness
  • Ease of reshaping
  • Conductivity
20
Q

What are the properties of ceramics?

A

Stiff but brittle material

21
Q

What are composites?

A

Made of different materials.

22
Q

What are alloys?

A

A mixture of metals and other elements

23
Q

What are polymers suited to?

A

Some are flexible, so can be moulded into any shape

Others are strong so can be used for objects like lunchboxes.

24
Q

What are ceramics suited to?

A

Windows as they are strong and hard wearing

25
Q

What are metals suited to?

A

Suited to corrosion materials as they are strong.

26
Q

What is a redox reaction?

A

Where a metal loses electrons when corroding.

27
Q

What is required for Iron to corrode?

A

Oxygen and water

28
Q

What methods are there to prevent corrosion?

A

Creating barriers between metal and water and oxygen:
-Painting / coating with plastic

Sacrificial method:
-galvanising iron with zinc. The zinc may corrode or be scratched but the iron will not

29
Q

What is the difficulty of extracting raw materials?

A

Requires energy

  • however products can be reused
  • the energy comes from burning fossil fuels
30
Q

How are plastic water bottles recycled?

A

Made from polymer PET.

  • plastic waste is sorted to seperate PET objects from other plastic materials
  • PET is shredded and cleaned, then melted to make new products
  • recycling PET is viable as it uses less materials than creating new PET.
31
Q

What are the difficulties with recycling?

A

Recycling requires energy and resources to collect materials, sort them.

32
Q

What does a life cycle assessment consist of?

A

1) Choice of material
2) Manufacture
3) Use of product
4) Disposal

33
Q

What does each stage of the life cycle assessment take in to account?

A
  • How much damage it will do to the environment
  • How much energy is required
  • Is it biodegradable?
34
Q

What is the size (diameter) of a nanoparticle?

A

0.000000001m

35
Q

Why do nanoparticles have a large surface:volume ratio?

A

A higher proportion of the atoms are at the surface are able to react with more substances.

36
Q

What are fullerences?

A

Nanoparticles of carbon
Arranged in rings similar to graphite
-have delocalised electrons, so can conduct
-high tensile strength

37
Q

How can nanopartiicles modify the properties of metals?

A
  • High surface:volume ratio so make good catalysts
  • can cause drugs to be absorbed easier
  • new coatings made with fullerences
  • conduct so can be used in circuits
38
Q

What do people worry about the effects of nanoparticles on health?-

A

People believe they are small and may have unexpected side affects

  • benefits have to be weighed up against the risks
  • people believe products containing nanoprticles have been made availble before tested on humans.