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using resources Flashcards

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1
Q

ceramics

A
  • non metal solid with high melting point that are not made from carbon - based compounds
  • some can be made from clay which is soft when dug up from ground and can be moulded into different shapes
  • when fired at high temps it can harden to form a clay ceramic
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2
Q

what is glass

A

it is a ceramic that is generally transparent and can be moulded when hot but it brittle when thin

most glass made from soda-lime glass

borosilicate glass has a higher melting point than soda lime glass

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3
Q

how do you make soda-lime glass

A

heat mixture of limestone sand and sodium carbonate until it melts, when it cools it comes out as glass

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4
Q

what makes borosilicate glass

A

a mixture of sand and boron trioxide

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5
Q

composites

A

made of one material embedded into another, fibres or fragments of a material (known as reinforcements) are surrounded by matrix acting as a binder

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6
Q

fiberglass

A

consits of fibres of glass embedded in matrix made of polymer

has low density but is very strong used for things like skis and surfboards

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7
Q

carbon fibre composites

A

have a polymer matrix and their reinforcement is either long chains of carbon atoms bonded together (carbon fibres) or carbon nanotubes

very strong and light used in aerospace and sports car manufacturing

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8
Q

concrete

A

made from aggregate (any material made from fragments usually sand and gravel in concrete) embedded in cement

very strong means its a good building material

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9
Q

wood

A

natural composite of cellulose fibres held together by an organic polymer matrix

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10
Q

what can influence properties of a polymer

A

how it is made and what it is made from
e.g properties of poly(ethene) can depend on catalyst that was used and reaction conditions it was made under

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11
Q

low density (LD) poly(ethene)

A

made from ethene at a moderate temp under a high pressure

it is flexible and used for bags and bottles

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12
Q

high density (HD) poly(ethene)

A

made from ethene but at a lower temp and pressure with a catalyst

it is more rigid and used for water tanks and drain pipes

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13
Q

what do monomers do

A

determine the type of bonds that form between the polymer

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14
Q

thermosetting polymers

A

contain monomers that can form cross-links between the polymer chnains holding them together in a solid structure

they do not soften when they are heated and are strong hard and rigid

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15
Q

thermosoftening polymers

A

contain individual polymer chains entwined together with weak forces between the chains, you can melt and remould them

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16
Q

properties of ceramics

A
  • glass and clay
  • used in porcelain and bricks
  • insulators of heat and electricity
  • brittle and stiff
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17
Q

properties of polymers

A
  • insulators of heat and electricity
  • can be felexible and easily moulded
  • used in clothing insulators and electrical items
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18
Q

properties of composites

A
  • depends on the matrix/nimder amd reinforcement used to make them
  • have many different uses
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19
Q

properties of metals

A
  • generally maleable
  • good conductors of heat and electricity
  • ductile shiny and stiff
  • used in electrical wires, car bodywork and cutlery
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20
Q

alloys

A
    1. made by adding another element to the metal that disrupts the metal’s structure
  • harder than pure metal
  • alloys of iron called steels are often used instead of pure iron
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21
Q

how are steels made

A

by adding small amounts of carbon and sometimes other metals to pure iron

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22
Q

types of steel and properties

A
  • low carbon steel (add little amount of carbon)- easily shaped and used for car bodies
  • high carbon steel (add more carbon) - very hard inflexible and used for blades for cutting tools and bridges
  • stainless steel (add chromium and sometimes nickel)- corrosion-resistant used for cutlery and containers for corrosive substances
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23
Q

examples of other alloys

A
  • bronze = copper + tin
  • brass = zinc + copper
  • gold added to things such as zinc copper and silver to harden it for jewellery
  • aluminium alloyed with small amounts of other metal to make it stronger and used to make an aircraft
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24
Q

carat gold system

A
  • pure gold is 24 carat
  • 18 carat means 18/24 parts of alloy are pure gold so essentially it would be 75% gold
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25
Q

corrosion

A
  • when a metal reacts with a substance in their environment and are gradually destroyed
  • only happens to surface that is exposed to air
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26
Q

corrosion of iron

A
  • iron rusts
  • to do this it needs the be in contact with oxygen and water which you can find in air
  • rust is actually the compound hydrated iron (III) oxide
  • it is soft and crumbly so flakes off which leaves more iron available to rust again meaning eventually all the iron in an object eventually corrodes away even if it wasn’t at the surface originally
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27
Q

corrosion of aluminium

A

not completely destroyed because the aluminium oxide formed when it corrodes doesn’t flake away but instead forms a nice protective layer that sticks firmly to the aluminium below and stops any further reaction taking place

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28
Q

an experiment to show both oxygen and water are needed for iron to rust

A
  • put iron nail in boiling tube with just water and it won’t rust (water boiled to remove oxygen and oil used to stop air getting in
  • put iron nail in boiling tube with just air and it won’t rust ( calcium chloride used to absorb water from the air)
  • put an iron nail in BT with air and water it will rust
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29
Q

ways to prevent rusting

A

barrier method
- painting/ coating with plasitc
- electroplating uses electrolysis to reduce metal ioms onto an iron electrode which can be used to coat the iron with a layer of different metal that won’t corrode
- oiling/ greasing has to be used when moving parts such as a bike chain are involved

Sacrificial method
- placing more reactive metal such as zinc or magnesium with the iron so water and oxygen react with that instead of the iron

30
Q

sustainable development

A

an approach to development that takes account of the needs of present society while not damaging the lives of future generations

31
Q

why can extracting resources not be sustainable

A

because of the amount of energy used and waste produced

32
Q

how to improve sustainability of copper

A
  • need to do this as copper-rich ores are limited
  • can improve sustainibility by extracting it from low-grade ores
  • can do this by bioleaching or phytomining
33
Q

bioleaching

A
  • bacteria used to convert copper compounds in ore into soluble copper compounds
  • this separates out the copper from the ore in the process
  • the leachate (solution produced by process) contains copper ions whihc can be extracted by electrolysis or displacement
34
Q

phytomining

A
  • grow plants in soil that contains copper
  • plants cannot get rid of or use copper so it will eventually build up in the leaves
  • plants then harvested, dried and burned in a furnace
  • the ash contains soluble copper compounds from which copper can be extracted by electrolysis or displacement
35
Q

benefits of recycling metals

A
  • extracting and mining them used a lot of energy which often comes from burning fossil fuels
  • recycling often uses less energy and conserves the finite amount of each metal in earth
  • it cuts down waste getting sent to landfill
36
Q

how to recycle metals

A
  • melt them and cast them into shape of new product
  • some need to be separated
37
Q

recycling of glass

A
  • glass bottles often reused without reshaping
  • other class cannot be reused so are recycled instead and usually separated by colour and chemical composition
  • glass is crushed then melted to be reshaped
38
Q

uses of recycled glass

A
  • insulating glass wool for wall insulation
  • bottles
  • jars
39
Q

what is a life cycle assessment and its stages

A

(LCA) looks at every stage of a products life to assess impact it would have on environment
- getting raw materials
- manufacturing and packing
- using product
- product disposal

40
Q

LCA: raw materials

A
  • can damage local environment e.g mining
  • can result in pollution due to amont of energy needed
  • raw materials often need to be processed to extract desired materials which needs a lot of energy
  • e.g fractional distillation of crude oil
41
Q

LCA: manufacturing and packaging

A
  • can use lots of energy resources and pollution e.g carbon monoxide
  • think about any waste and how to dispose of them
  • chemical reactions used to make compounds from raw materials can produce waste products
  • however some waste can be turned into other useful chemicals
42
Q

LCA: using product

A
  • can damage the environment e.g burning fossil fuels releases greenhouse gasses
  • fertilisers can leach into streams and rivers causing damage to ecosystems
  • how long it is used and how many uses it gets
  • e.g products that use lots of energy but are used for ages mean less waste in long run
43
Q

LCA: disposal

A
  • being disposed in landfill takes up space and pollutes land and water e.g paint may wash off in landfill and pollute a river
  • energy used to transport waste to landfill causes pollutants to be released
  • products may be incinerated which causes air pollution
44
Q

problems with LCA

A
  • sometimes uses of energy, natural resources and waste produced by a product over a lifetime is not easily quantifiable
  • can be biased as it often takes into account the values of the person carrying it out
  • selective LCAs can be written to deliberately support claims of a company in order to give them positive advertising
45
Q

potable water

A
  • water that has been treated or is naturally safe for humans to drink
  • not pure as it contains dissolved substances other than H2O
  • pH between 6.5-8.5/
46
Q

source of fresh water and location

A
  • sometimes it can be collected as surface water in lakes and rivers
  • other times collected as groundwater in rocks called aquifers that trap water underground
  • in warm areas (such as south east) surface water tends to dry up so most domestic water supply comes from groundwater
47
Q

process to make water potable

A
  • filtration - a wire mesh screens out large twigs and gravel and sand beds filter out other solid bits
  • sterilisaton - water is sterilised to kill harmful bacteria or microbes can be done by bubbling chlorine gas through it or by using ozone or ultra violet
48
Q

sea water

A

in dry countries where there isn’t enough surface or ground water, sea water needs to be used
- treated by desalination
- or a process that uses membranes - like reverse osmosis and it only allows water molecules through ions and larger molecules are separated from the water
these both need loads of energy and are very expensive and are not practical for producing large quantities of fresh water

49
Q

PRACTICAL: distilling water in a lab

A
  • test pH of water and if it is too high or low you need to neutralise it with acid or alkali depending
  • pH must be between 6.5-8.5
  • test for prescence of sodium chloride iions by a flame test (sodium ions = yellow) and add nitric acid and silver nitrate solution (chloride ions = white precipitate)
  • to distill pour salty water into distillation apparatus heat flask from below
  • water will form steam and leave salt in flask, steam will condense back into liquid water in the condenser
  • then retest for sodium chlorine and retest pH
50
Q

where does waste water come from

A
  • goes to sewers and towards sewage treatment plans
  • agricultural systems also produce a lot of waste w ater like nutriet run off from fields and dlurry from farm animals
  • this waste water has to be treated to remove any organic matter and harmful microbes before it can be put back into fresh water sources like rivers and lakes
  • haber process also produces waste water which has harmful chemicals in it so must undergo additional stages of treatment before it is safe to release into environment
51
Q

steps of sewage treatment

A
  1. screening - remove large bits of material and grit
  2. sedimentation - heavier solids go to bottom (sludge) lighter effluent floats to top
  3. sludge goes through anaeroobic digestion (breaks down organic matter releasing methane gas which can be used as energy source and remaining digested waste used as fertiliser)
  4. gas digested and wate produced
  5. effluent goes through aerobic digestion (air pumped through water encouraging aerobic bacteria to break down organic matter and other microbes in water)
  6. then water released back into environment
52
Q

what happens to waste containing toxic substances

A

addional stages of treatment such as adding chemicals to precipitate metals, UV radiation or using membranes

53
Q

equation for haber process

A

nitrogen (N2) + Hydrogen (3H2) –> ammonia (2NH3) (+heat)

it is reversable

54
Q

why is it well suited for an industrial scale

A
  • reactants not to difficult or expensive to obtain
  • air is 78% nitrogen
  • hydrogen can come from reacting methane with steam (prodycts hydrogen and carbon dioxide)
55
Q

how does haber process happen

A
  • reactant gases passed over iron catalyst at high temp (450) and high pressure (200 atmospheres)
  • because it is reversable some ammonia converts back to hydrogen and nitrogen and eventually reached dynamic equilibrium
  • ammonia is a gas but cools and liquifies in condenser and is removed
  • unused hydrogen and nitrogen are recycled so nothing is wasted
56
Q

what can ammonia produced be used to make

A

ammonium nitrate which is a very nitrogen rich fertiliser

57
Q

what is forward reaction in haber process

A

exothermic so increasing temp will move equilibrium the wrong way

58
Q

why can haber process not be done at low temp

A

slower rate of reaction so equilibrium is reached more slowly

59
Q

why is pressure high

A
  • 4 molecules on left and side and 2 on right hand side so increasing temp increases yeild
  • also higher pressure increases rate of reaction
  • therefore pressure is set as high as possible without making the process too expensive
60
Q

what does the iron catalyst do

A

increases rate of reaction but doesn’t affect yeild

61
Q

why are fertilisers used

A
  • widely available
  • easier to use than manure
  • don’t smell
  • have just enough of each nutrients so more crops can be grown
62
Q

how do fertilisers help

A
  • essential elements are nitrogen, phosphorus and potassium
  • if plants don’t get enough of these their growth and life processes are affected
  • these elements may be missing from soil is used up by earlier crop
  • fertilisers replace these missing elements to increase crop yield as crops can grow faster and bigger
63
Q

NPK fertilisers

A

formulations containing
- salts of nitrogen
- phosphorus
- and potassium
these are in the right percentages of the elements

64
Q

how is ammonia used to produce nitrogen containing compounds

A
  • reacted with oxygen and water in a series of reactions to make nitric acid
  • can react ammonia with nitric acid to get ammonium salts that can be used for fertililsers
  • ammonia + nitric acid -> ammonium nitrate
65
Q

why is ammonium nitrate good

A

it has nitrogen from two sources

66
Q

ammmonium nitrate production in industry

A
  • carried out in giant vats at high concentrations resulting in very exothermic reaction
  • heat released used to evaporate water from mixture to make very concentrated ammonium nitrate product
67
Q

ammonium nitrate production in the lab

A
  • carried out on smaller scale by titration and crystillisation
  • reactants at lower concentration so less heat produced making it safer
  • after titration mixture needs to be crystillised to give pure ammonium nitrate crystals
  • crystillisation not used in industry as it is very slow
68
Q

what can be mined and used as source of potassium

A

potassium chloride and potassium sulphate

69
Q

problems with mining phosphate rock

A

insoluble so plants cannot directly absorb them and use them as nutrients

70
Q

reactions of phosphate rock

A
  • with nitric acid to produce phosphoric acid and calcium nitrate
  • with sulfuric acid to produce calcium sulfate and calcium phosphate (single superphosphate)
  • with phosphoric acid to produce calcium phosphate (triple super sulphate)
71
Q

reaction with sulphuric acid produces

A

single superphosphate

72
Q

reaction with calcium phosphate produces

A

triple superphosphate

Chemistry (6 decks)

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