Materials - Unit 2 Topic 7

Question 1

What is the definition of natural materials?

Answer 1

Materials derived directly from natural materials.

Question 2

What is the definition of synthetic materials?

Answer 2

Materials made when raw materials are put through a manufacturing process to make a synthetic material.

Question 3

Gold, limestone, polythene, linen, rubber, copper, wood, Kevlar, aluminium, granite, polyester, Pyrex.
Which of these are natural and which are synthetic?

Answer 3

Natural - Gold, limestone, linen, wood, copper, aluminium, granite.
Synthetic - Polythene, rubber, Kevlar, polyester, Pyrex.

Question 4

What manufactured materials can you obtain from rock?

Answer 4

Aluminium from bauxite
Glass from sand, limestone + sodium carbonate
Ceramics from sand + clay
Lime from limestone

Question 5

What manufactured materials can you obtain from crude oil?

Answer 5

Fuels, plastics + detergents

Question 6

What manufactured materials can you obtain from air?

Answer 6

Nitrogen + oxygen

Question 7

What manufactured materials can you obtain from sea water?

Answer 7

Salt, iodine, hydrogen + sodium hydroxide.

Question 8

What manufactured materials can you obtain from plants?

Answer 8

Fuels from biomass, cotton + medicines.

Question 9

What is nanotechnology?

Answer 9

Relatively new science that is the study of atoms and molecules.

Question 10

What does nanometre mean?

Answer 10

10-9m

Question 11

What size of particles does nanotechnology refer to?

Answer 11

1 - 10nm in size

Question 12

What is the difference between nanoparticles and larger particles?

Answer 12

Larger surface area to volume ratio.

Question 13

What are gold nanoparticles used for?

Answer 13

Catalysts to convert CO to CO2

Question 14

Give 3 properties of silver nanoparticles?

Answer 14

Antibacterial, antiviral and antifungal.

Used to sterilise hospital equipment.

Question 15

Give 2 uses for nanotubes.

Answer 15

Mini electronic devices and smaller, faster computers.

Question 16

How are nanoparticles used as coatings?

Answer 16

Thin layers of scratch resistant polymer can be used to protect lenses of glasses, contacts and cameras. Layers of polymer can also be used to make fabric stain resistant.

Question 17

What are the conflicting reports about nanomaterials?

Answer 17

Some reports say they are harmless but others claim they may damage human cells.

Question 18

Why would the ‘Take Back’ policy ensure nanomaterials would not affect the environment?

Answer 18

The policy would ensure that no nanmaterials would end up in waste and therefore that they would not affect the environment.

Question 19

What is the health concern with carbon nanotubes?

Answer 19

The nanotubes can behave like asbestos when inhaled.

Question 20

Why do engineers say that carbon nanotubes are safe?

Answer 20

Engineers claim that the nanotubes cannot be inhaled as they would be bound up in electrical products.

Question 21

What are the two most common ways of extracting a metal from its ore?

Answer 21

Chemical reduction using carbon or carbon monoxide.

Electrolysis

Question 22

Why do metals higher than carbon in the reactivity series have to be extracted using electrolysis?

Answer 22

Metals high in the reactivity series are very reactive and need a powerful method to extract them.

Question 23

Metals below carbon in the reactivity series can be extracted by reduction using carbon. How does it work?

Answer 23

Carbon can take the oxygen away from the metals which are less reactive than the carbon itself is.

Question 24

Method of extraction for:
Potassium
Sodium 
Calcium
Magnesium
Aluminium

Answer 24

Electrolysis
Electrolysis
Electrolysis
Electrolysis
Electrolysis

Question 25

``` Method of extraction for: Zinc Iron Lead Copper Silver Gold ```

Answer 25

``` Heat with carbon/carbon monoxide Heat with carbon/carbon monoxide Heat with carbon/carbon monoxide Roasting in air Occur naturally Occur naturally ```

Question 26

What is electrolysis?

Answer 26

When an electrical current passes through a liquid that causes a chemical reaction. The reaction is a breakdown of the substance into simpler substances.

Question 27

What is an electrolyte?

Answer 27

An ionic compound that has been melted or dissolved in water.

Question 28

What is a cathode?

Answer 28

The electrode attached to the negative pole.

Question 29

What is an anode?

Answer 29

The electrode attached to the positive pole.

Question 30

What is a cation?

Answer 30

Positive ion

Question 31

What is an anion?

Answer 31

Negative ion

Question 32

What is an electrode?

Answer 32

Metal strips or graphite rods placed into the liquid and connected to a supply of electricity.

Question 33

What happens to the anions at the anode?

Answer 33

They lose electrons and become neutral atoms.

Question 34

What happens to the cations at the cathode?

Answer 34

They gain electrons and become neutral atoms.

Question 35

Why are the electrodes made of graphite?

Answer 35

It is a good conductor of electricity and unreactive.

Question 36

Label diagram of electrolysis of a molten electrolyte.

Answer 36

Page 6

Question 37

Why does the electrolysis of lead bromide need to be carried out in a fume cupboard?

Answer 37

It produces a harmful gas which must be contained.

Question 38

What product is formed at the cathode during the electrolysis of lead bromide?

Answer 38

Silver bead of lead

Question 39

What product is formed at the anode during the electrolysis of lead bromide?

Answer 39

Brown bromine fumes

Question 40

Why can't lead bromine conduct electricity when solid?

Answer 40

Ions can't move.

Question 41

What product is formed at the cathode during the electrolysis of lithium chloride?

Answer 41

Silver grey liquid lithium.

Question 42

What product is formed at the anode during the electrolysis of lithium chloride?

Answer 42

Yellow-green chlorine gas

Question 43

In the electrolysis of molten lead bromide, name a piece of apparatus that can be connected in the circuit to show that an electric current is flowing through the electrolyte.

Answer 43

Light bulb

Question 44

What is the name of aluminium's ore?

Answer 44

Bauxite

Question 45

What is added to pure aluminium oxide before it is electrolysed?

Answer 45

Molten Cryolite

Question 46

At what temperature is the electrolysis of aluminium carried out?

Answer 46

900c

Question 47

State 2 purposes of cryolite.

Answer 47

Lowers the melting temperature of bauxite | Increases conductivity

Question 48

How is molten aluminium removed from the cell in the electrolysis of aluminium?

Answer 48

Tapped off

Question 49

Why is the electrolysis of aluminium from its ore more expensive than the extraction of iron from its ore?

Answer 49

Electricity is expensive

Question 50

Why does the anode have to be replaced during the electrolytic extraction of aluminium?

Answer 50

Oxygen at anode reacts with carbon electrode at high temperature which produces CO2 gas and wears it away.

Question 51

Label diagram of the electrolysis of aluminium from its ore.

Answer 51

Page 10

Question 52

Where should an aluminium extraction plant be sited?

Answer 52

Near cheap source of electricity such as hydroelectric power station, good transportation links, good water supply, waste disposal facilities, skilled workforce nearby + not close to any areas of natural beauty or conservation areas.

Question 53

What percentage of aluminium cans are recycled? What percentage of energy does recycling aluminium use compared to electrolysis of bauxite? Is it cheap or expensive?

Answer 53

26% 5% Most cost effective material to recycle.

Question 54

What are 3 negative effects of mining on the local environment?

Answer 54

Noise pollution , dust pollution + destroying natural habitats.

Question 55

State 3 uses for aluminium?

Answer 55

Drink cans, aircraft bodies + door frames.

Question 56

Label diagram of the blast furnace.

Answer 56

Page 12

Question 57

Name an ore from which iron can be extracted.

Answer 57

Haematite

Question 58

What are the stages of extracting iron from the blast furnace?

Answer 58

Hot oxygen blown into base of furnace + coke burns to heat it to 1500c forming CO2 which reacts with more coke to from CO. CO reduces FeO to Fe. Limestone added which thermally decomposes to CaO which combines with sandy impurities (silicon dioxide) to form slag (calcium silicate) which floats on top. Hot waste gases heat air pumped into bottom of furnace. Carbon (pig iron) is turned into steel by lowering carbon content and adding other metals.

Question 59

What are the waste gases formed when extracting iron from the blast furnace?

Answer 59

Nitrogen, CO + CO2.

Question 60

What is slag used for?

Answer 60

Making roads, landfill + foundations for buildings.

Question 61

In what ways does the manufacture of iron help the economy?

Answer 61

Provides jobs, cheap + produces exports.

Question 62

What environmental problems arise with iron manufacture?

Answer 62

Polluting air, noise pollution, destroying natural habitats + unsightly slag heaps.

Question 63

What raw materials are used in the extraction of iron ore?

Answer 63

Limestone, coke, hot air + iron ore.

Question 64

What is the main purpose of adding limestone to the blast furnace when extracting iron?

Answer 64

Removing acidic impurities.

Question 65

What are the disadvantages of recycling?

Answer 65

Sorting recycled materials is labour intensive and expensive.

Question 66

What are the advantages of recycling?

Answer 66

Less mining, less energy use, less pollution, less natural habitat destruction, fewer eyesores + saves resources.

Question 67

What are the disadvantages of incinerating/landfill?

Answer 67

Toxic gases released, wastes land, ash residue toxic + needs specialised landfill needed, incineration prevents landfill + more transport of waste to incineration sites than to landfill.

Question 68

What are the advantages of incinerating/landfill?

Answer 68

Heat energy harnessed to generate electricity.

Question 69

What are the disadvantages of production of new materials?

Answer 69

More mining, more raw materials used, more energy used, more pollution, more destruction of habitats + more eyesores created.

Question 70

What are the advantages of production of raw materials?

Answer 70

Workforce skilled in industrial processing.

Question 71

Where is bauxite imported from?

Answer 71

NW Africa, Central America, Jamaica + Australia.

Question 72

What properties of aluminium make it useful to the electrical industry?

Answer 72

Good conductor + low density.

Question 73

What percentage of carbon is found in cast iron produced by the blast furnace? What change occurs to amount of carbon when converted to steel + why?

Answer 73

4% | Reduced to 1% as removing carbon makes it less brittle.