polymer Flashcards

1
Q

Why can metals conduct electricity?

A

They have delocalised electrons, which are free to move around the whole structure, and carry an electrical charge

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2
Q

Why are metals malleable?

A

They are arranged in layers which can slide over each other

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3
Q

Why do they have high melting and boiling points?

A

They have lots of strong forces of attraction which need a lot of energy to overcome

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4
Q

what are the properties of metals ?

A
Strong
High melting point
Shiny
Good electrical and thermal conductors
Flexible
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5
Q

what are the properties of a non-metals?

A

Brittle
Low melting point
Dull
Poor electrical and thermal conductors

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6
Q

Why are metals used in pans?

A

They conduct heat

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7
Q

Why are they used in buildings?

A

They are strong

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8
Q

Why are they used in wires?

A

They are ductile and conduct electricity

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9
Q

Define an alloy

A

A metal mixed with another element

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10
Q

List 3 natural and 3 synthetic materials

A

Natural materials include wood, water, air, sand etc
Synthetic materials include glass, paper, plastics
Synthetic materials are man made

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11
Q

Steel is used in building because…

A

they are strong and hard

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12
Q

Copper is used in electrical items because…

A

they are good conductor of electricity

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13
Q

China is used for tea pots because…

A

they are good thermal insulator

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14
Q

2 strong materials are…

A

Steel, iron (metals)

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15
Q

2 thermal insulators are…

A

Plastic, rubber

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16
Q

2 conductors (thermal and electrical) are…

A

Iron, aluminium

17
Q

Describe 6 things a bar chart needs

A
X axis labels
Y axis labels
Suitable scale
Gaps between bars
Bars equal width
Bars drawn to the correct height
18
Q

Explain why substances are brittle

A

Atoms are in a rigid structure and can’t move past each other

19
Q

Explain why substances are hard

A

Lots of strong bonds in a giant lattice

20
Q

Explain why substances have high melting points

A

Lots of strong bonds which require a lot of thermal energy to break

21
Q

Explain why substances can conduct electricity

A

Delocalised electrons which are free to move around the structure and carry a charge

22
Q

Describe and explain the conditions needed to form large crystals in ceramic materials.

A

Allowing them to cool slowly, which means there is enough time for the lattice structure to form

23
Q

Define polymer

A

Lots of small molecules joined together in a long chain.

24
Q

Give 2 examples of polymers

A

PVC, polystyrene

25
How are polymers formed?
From monomers, repeat units, joined together
26
Plastic means:
It will not return to its original shape when stretched
27
Elastic means:
It will return to its original shape when stretched
28
A composite material is
two or more materials combined with some of the properties of each
29
Give 2 examples of composites
Paper | Concrete
30
What 4 things do you need to make concrete?
Cement Sand Aggregate Water
31
Define thermal decomposition:
Where a compound is broken down into simpler substances using heat energy
32
What is the word equation for thermal decomposition of calcium carbonate?
Calcium carbonate → Calcium oxide + carbon dioxide
33
Give 3 reasons for recycling plastics:
To preserve natural resources To save energy Some substances are not biodegradable (they are not broken down by living organisms)
34
How do you recycle metals?
Separate them then melt them
35
How do you recycle glass?
Sort by colour, crush and melt them
36
How do you recycle plastic?
Melt and mould into new materials
37
State and explain how the properties of vulcanised rubber differ from natural rubber
Cross links increases its melting point and makes it harder - more bonds to overcome. Cross links increases elasticity - layers can return to their original positions