Using materials (10.3)

Question 1

What is corrosion?

Answer 1

The destruction of materials by chemical reactions with substances in the environment

Question 2

What s an example of corrosion?

Answer 2

Rusting

Question 3

What is necessary for iron to rust?

Answer 3

Both air and water

Question 4

How can corrosion be prevented?

Answer 4

By applying a coating that acts as a barrier, such as greasing, painting or electroplating

Electroplating is the process of coating a metal with a thin layer of another metal by depositing it in electrolysis to improve the metal’s corrosion resistance

Question 5

How is aluminium prevented from further corrosion?

Answer 5

It has an oxide coating that protects the metal

Question 6

Describe sacrificial protection

Answer 6

Some coatings are reactive and contain a more reactive metal that will react with air and water before the less reactive metal to give it protection

Question 7

What is an example of sacrificial protection?

Answer 7

zinc is used to galvanise (protect) iron

Question 8

Most metals in everyday use are (…)

Answer 8

alloys

Question 9

What is bronze?

Answer 9

an alloy of copper and tin

Question 10

What is brass?

Answer 10

an alloy of copper and zinc

Question 11

What is gold used in jewellery usually?

Answer 11

an alloy with silver, copper and zinc

as gold is very soft and malleable

Question 12

What is the proportion of gold in the alloy is measured in?

Answer 12

carats

Question 13

Describe 24 and 18 carat gold

Answer 13

24 carat - 100% (pure gold)

18 carat - 75%

Question 14

What are steels?

Answer 14

alloys of iron that contain specific amounts of carbon and other metals

Question 15

Describe the properties of high carbon steel

Answer 15

High carbon steel is strong but brittle

Question 16

Describe the properties of low carbon steel

Answer 16

Low carbon steel is softer and more easily shaped/malleable (than high carbon steel)

Question 17

What are stainless steels?

Answer 17

Steels containing chromium and nickel

Question 18

What are the properties of stainless steels?

Answer 18

They are hard and resistant to corrosion (rusting)

Question 19

Aluminium alloys are (…) density

Answer 19

low

so is light

Question 20

What is bronze used to do?

Answer 20

To make coins

Question 21

What is brass used to do?

Answer 21

to make musical instruments

Question 22

What is a use of gold?

Answer 22

used in jewellery

Question 23

What is a use of high carbon steels?

Answer 23

used in construction

Question 24

What is a use of low carbon steels?

Answer 24

used for making car body panels

Question 25

What is a use of stainless steel?

Answer 25

used for cutlery

Question 26

What is a use of aluminium alloys?

Answer 26

Aluminium foil for storing/wrapping foods *as is malleable and light/low density*

Question 27

Which glass is the one we mostly use?

Answer 27

soda-lime glass

Question 28

How is soda-lime glass made?

Answer 28

by heating a mixture of sand, sodium carbonate and limestone

Question 29

What is borosilicate glass made from?

Answer 29

sand and boron trioxide

Question 30

Borosilicate glass melts at (…) temperatures than soda-lime glass

Answer 30

higher

Question 31

# 2 needed What are examples of clay ceramics?

Answer 31

pottery and bricks

Question 32

How are clay ceramics made?

Answer 32

by shaping wet clay and then heating in a furnace *can be a property as well*

Question 33

What do the properties of polymers depend on?

Answer 33

* what monomers they are made from * the conditions under which they are made

Question 34

Low density (LD) and high density (HD) poly(ethene) are produced from what?

Answer 34

Ethene

Question 35

Describe thermosoftening polymers

Answer 35

polymers that melt when they are heated *(so can be recycled)*

Question 36

Describe thermosetting polymers

Answer 36

polymers that do not melt when they are heated

Question 37

What is the difference in how LDPE and HDPE are made and their structure?

Answer 37

LDPE - formed at very high pressures with trace of oxygen, ethene forms LDPE - polymer chains randomly arranged HDPE - using catalyst of 50^oC and a sightly higher pressure - polymer chains branch less and so molecules line up more closely

Question 38

Describe the structure of thermosoftening polymers

Answer 38

No covalent bonds between large molecules (chains), which are tangled together so no cross links So no/very weak intermolecular forces so molecules can move over each other when heated and the plastic melts and are easily overcome

Question 39

Describe the structure of thermosetting polymers

Answer 39

Strong covalent bonds forming ‘cross links’ between polymer chains so strong intermolecular forces and held in position so molecules only vibrate when heated, so are unable to move

Question 40

What are most composites made from?

Answer 40

Two materials with different properties,

Question 41

What are the components found in a composite?

Answer 41

a matrix or binder surrounding and binding together the reinforcement (fibres or fragments of the other material)

Question 42

What is the reinforcement in a composite?

Answer 42

fibres or fragments of the other material

Question 43

# non-specification list What are some examples of composites?

Answer 43

Question 44

Which type of glass would be best to make a boiling tube in a school lab? Why?

Answer 44

Borosilicate glass would be best because it has a higher melting point than soda-lime glass. This means that it will not melt when it is heated using a Bunsen burner.

Question 45

# 3 needed What are the physical properties of glass ceramics?

Answer 45

* transparent * hard * but is brittle (breaks easily)

Question 46

# 2 needed What are the physical properties of clay ceramics?

Answer 46

* resist compressive forces (can withstand weight and pressure) * when wet can be shaped and then hardened at high temperatures

Question 47

# 3 needed What are the physical properties of polymers?

Answer 47

* poor conductors of heat and electricity, hence they are good thermal and electrical insulators * LDPE for structures that require flexibility * HDPE for structures that require rigid, strong structures to withstand pressure *useful for electrical wiring as they prevent overheating and an electric shock*

Question 48

# 1 for general property What are the physical properties of composites?

Answer 48

* The properties of composites depend on the reinforcement and matrix used so composites can be **tailor engineered** to meet specific needs * E.g. steel reinforced concrete has immense* ***tensile*** *and* ***compressive strength***

Question 49

What are shape memory alloys (materials)?

Answer 49

Alloys/materials that can be deformed when cold, but return to their original shape when heated

Question 50

Give two reasons why wood is more sustainable than natural gas as a fuel

Answer 50

* Wood is renewable, natural gas is not * Wood is carbon-neutral, natural gas is not

Question 51

What is one property of a smart polymer that is different to that of an ordinary polymer?

Answer 51

has a shape memory **or** a smart polymer can return to original shape when conditions change

Question 52

Give three properties of gold

Answer 52

is very soft malleable unreactive (so resists corrosion and stays shiny)

Question 53

Cast iron is (…)

Answer 53

brittle

Question 54

# 2 needed - 4 you could give Catalysts have been developed to allow the reactions to occur at lower temperatures - why might this be of benefit to the manufacturer and environment?

Answer 54

* more product obtained (in shorter time) * Less fuel costs * Less pollution caused by burning fuels * Using less fuel conserves energy resources