C15 - Using our resources (Part 1 - Corrosion, Alloys, Ceramics and Composites, Polymers) Flashcards

1
Q

What is corrosion

A

Corrosion is the destruction of materials by chemical reactions with substances in the environment

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2
Q

What is rusting

A

A corrosion process where ONLY iron or steel reacts with BOTH water and oxygen

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3
Q

How to set up the rusting experiment

A
  • Set up 3 test tube
  • First test tube with distilled water open to air
  • Second with boiled water (removes O2) with a layer of oil over it
  • Third with anhydrous calcium chloride (removes water) and a bung to stop water vapour entering
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4
Q

Methods to prevent corrosion

A
  • Paint
  • Oil/grease
  • Electroplating w/ aluminium which forms aluminium oxide
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5
Q

What is galvanising and what does it do

A
  • Coating a metal with zinc
  • Zinc is more reactive so corrodes instead through SACRIFICIAL PROTECTION
  • Acts as a barrier against water and oxygen
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6
Q

What is sacrificial protection

A

A more reactive metal than steel or iron placed over it so it oxidises before the steel/iron and prevents it from rusting

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7
Q

What is an alloy

A

A metal that have small amounts of another metal or carbon added

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8
Q

What is bronze an alloy of and what are its uses

A
  • Mixture of copper and tin
  • Used to make statues and bells
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9
Q

What is brass an alloy of and what are its uses

A
  • Mixture of copper and zinc
  • Used to make musical instruments and door handles
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10
Q

Properties and uses of aluminium alloys

A
  • Low density but strong
  • Can be used for aeroplanes and armour plating
  • Also used for OVERHEAD CABLES
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11
Q

What metals are in gold alloys and what are they used for

A
  • Gold is alloyed with silver, copper and zinc
  • Used for jewelery
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12
Q

What is used to measure the proportion of gold in an alloy

A

Carats e.g. pure gold is 24 carats

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13
Q

Properties and uses of low carbon steel

A
  • Soft + easily shaped
  • Used to make car bodies
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14
Q

Properties and uses of high carbon steel

A
  • Strong but brittle
  • Used in construction and cutting tools
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15
Q

What is stainless steel an alloy of and what are its properties and uses

A
  • Iron alloyed with chromium and nickel
  • Hard and resistant to corrosion
  • Used for cutlery
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16
Q

What is soda lime glass used for and how is it made

A
  • Made by mixing sand, sodium carbonate and limestone(calcium carbonate)
  • This is then heated in a furnance
  • It cools into any intended shape
  • Used for windows, wine glasses etc.
17
Q

How is borosilicate glass made

A
  • Made by melting a mixture of sand and boron trioxide
18
Q

Properties and uses of borosilicate glass

A
  • High melting point
  • Used in kitchenware and labware
19
Q

How are clay ceramics made

A
  • Clay found in ground
  • Clay is wettened and shaped
  • It is put in a high temp. furnace and heated
20
Q

How are composites made

A
  • You get a reinforcement which is small fibres or fragments of a material
  • The reinforcement is surrounded by a maxtrix or binder material
  • This means composites have different properties that the materials in them
21
Q

Examples of composites

A
  • Carbon fibre - strong and light
  • Reinforced concrete
  • Plywood + MDF
  • Fibreglass
22
Q

What does the properties of a polymer depend on

A
  • The monomers they are made from
  • The conditions used to make the polymer
23
Q

Things to change in order to change the properties of the polymer

A
  • Reaction temperature
  • Reaction pressure
  • Catalyst
24
Q

What happens when you heat and cool a thermosoftening polymer

A
  • They melt allowing reshaping (+recycling)
  • They go back to a solid when cooled
25
Q

Structure of a thermosoftening polymer

A

Randomely tangled polymer chains with weak intermolecular forces
These break under heat, melting the substance

26
Q

What happens when you heat a thermosetting polymer

A

They burn and this means they can’t be recycled or reshaped

27
Q

Structure of a thermosetting polymer

A
  • Strong covalent bonds (cross links) between polymer chains
  • Bonds just as strong as the ones between monomers
  • This means only when the polymer breaks will the cross links break leading to burning