Using Resources - Y11 Flashcards
1
Q
What are ceramics?
A
- Non-metal solids
- High melting points
- Some can be made of clay
Example is glass
2
Q
What is clay?
A
- Soft material when it’s dug up out of the ground
- Can be moulded into shapes
3
Q
What happens when clay is fired at high temps?
A
Hardens to form a clay ceramic
4
Q
What is clay ideal for?
A
Pottery and bricks
5
Q
What is glass?
A
- Transparent
- Can be moulded when hot
- Brittle when thin
6
Q
What is most glass made out of? How is it formed?
A
- Soda-lime glass
- Made by heating a mixture of limestone, sand and sodium carbonate unti; it melts
- When mixture cools, it forms glass
7
Q
What has a higher melting point than soda-lime glass? How is it made?
A
- Borosilicate glass
- Same way as soda-lime glass, using a misture of sand and boron trioxide
8
Q
What are composites? What 2 components make them up?
A
Made of one material embedded in another
* * Made of a matrix and reinforcement
9
Q
Reinforcement
A
- Consists of fibres or fragments of a material
- Is then surrounded by a matric or binder material
10
Q
Name 4 composities
A
- Fibreglass
- Carbon fibre
- Concrete
- Wood
11
Q
Fibreglass
A
- Consists of fibres of glasses embedded in a matrix made of polymer (plastic)
- Low density (like plastic)
- Very strong (like glass)
- Used for skis, boats, surfboats
12
Q
Carbon fibre
A
- Has a polymer matrix
- Reinforcement is made from long chain of carbon atoms bonded together (carbon fibres) or carbon nanotubes
- V strong and light
- Used in aaerospace and sports car manufacturing
13
Q
Concrete
A
- Made from aggregate (mix. of sand and gravel) embedded in cement
- V strong
- Building material
14
Q
Wood
A
- Natural composite of cellulose fibres held together by an organic polymer matrix
15
Q
What could you do to change the properties of a polymer?
A
- Change reaction temperature
- Reaction pressure
- Catalyst
16
Q
Thermosoftening polymers
A
- Melt when heated
- Can reshape them while they’re soft
- Turns solid when cooled down
17
Q
Melting of thermosoftening polymers process
A
- Intermolecular forces break when heated
- Polymer strands can separate from each other and polymer melts
- Cooling causes intermolecular forces to reform, polymer turns solid
18
Q
Thermosetting polymers
A
- Don’t melt when heated
- Strong, hard, rigid
- Connected by strong crosslinks - not broken by heat - solid structure
19
Q
Low density poly(ethene)
A
- made from ethene
- made at moderate temp and high pressure
- Flexible
- Used for bags and bottles
20
Q
High density poly(ethene)
A
- Made from ethene
- Made at low temp and pressure
- With catalyst
- More rigid than LD
- Used for water tanks and drain pipes
21
Q
Properties of ceramics (glass, clay ceramics like porcelain and bricks)
A
- Insulators of heat and electricity
- Brittle
- Stiff
22
Q
Properties of polymers
A
- Insulators of heat and electricity
- FLEXIBLE
- Easily moulded
- Clothing, insulators in electrical items
23
Q
Properties of composties
A
- depend on the matrix/binder and reinforcement used to make them, many diff uses
24
Q
Properties of Metals
A
- Malleable
- Good conductors of heat and elec.
- Ductile
- Shiny
- Stiff
- Cutlery, car body work, elec. wires
25
What is bronze an alloy of? Uses?
Copper and tin
Medals, statues, decorative ornaments
26
What is brass an alloy of? Uses?
Copper and zinc
water taps, musical instruments, doorknobs
27
Gold
* Zinc, copper, silver used to harden gold
* Pure gold is soft
* 24 carat = 100%
* 18 carat = 75%
28
Aluminium alloys
* Low density
* Pure Al is soft
* Good for aircrafts
29
High carbon steel vs low carbon steel
High = Strong but brittle - cutting tools, bridges
Low = Softer, easily shaped - car bodies
30
Steels containing what are resistant to what
* Containing chromium and nickel (stainless steels) because steel is an alloy of iron which can rust
* are hard and resistant to corrosion
* used for cutlery
31
What metal is the word "rust" for? Wb other metals?
Iron can rust
Other metals corrode
32
How does iron rust?
Needs to be in contact with water and oxygen (present in air)
33
What is rust in scientific words?
Hydrated iron (III) oxide
34
Equation for formation of rust
iron + oxygen + water -> Hydrated iron (III) oxide
35
Where does corrosion only happen?
Surface of a matieral where its exposed to air
36
Does rust flake off? How does this affect the whole object?
* Soft crumbly slid flakes off to leave more iron to rust again
* All iron will corrode away one day
37
Aluminium corrosion facts
* Corrodes when exposed to air
* Not completely destroyed like iron
* Alumnium oxide forms when Al corrodes doesnt flake away
* Forms a nice protective layer, stops further reaction
38
# Will it rust?
Iron nail is in test tube in distilled water, open to air
Yes
39
# Will it rust?
Nail is boiled, distilled oil covered in oil
No, boiled water removed any dissolved air
Oil prevents any air in test tube from dissolving in water
40
# Will it rust?
Nail is anhydrous calcium chloride powder with rubber bung
No, powder removes any water from the air in the test tube
Bung prevents moist air entering
41
4 ways to prevent rusting
* Painting/ coating with plastic = big and small structures
* Electroplating
* OIling/greasing - for moving parts eg bike chains
* Sacrificial method (Coating with zinc)
42
Sacrifical method
* Placing more reactive metal like zinc or mg
* Water and oxygen react with sacrifical metal instead of iron (sacrifical protection)
43
Galvanising
* object galvanised by spraying it with layer of zinc
* layer is firstly protective
* if scratched, zinc around site of scratch works as a sacrifical metal
44
Electroplating
* Electrolysis to reduce metal ions onto an iron electrode
* can be used to coat iron w/ layer of a diff metal that wont be corroded away
45
Corrosion
Destruction of material by chem reactions with substances in the environment
46
What are natural resources?
* Resources that form without human input
* anything from the earth, sea, air
47
What is done with some natural products?
* Replaced by synthetic products
* Or improved upon by man-made processes
48
How has rubber been modified?
* Rubber originally comes from sap from trees
* Man-made polymers can replace rubber in uses like tyres
49
How has agriculture been modified?
* Fertilisers = high yield of crops
50
Is timber a renewable resource?
* Yes
* Takes a few yrs to grow
51
Examples of finite resources
* Fossil fuels
* Nuclear fuels like uranium and plutonium
* Minerals and metals found in ores
52
What hapens when finite resources have been extracted? Give an eg
* Undergo Man-made processes to provide fuels and materials for modern life
* Fractional Distillation - produces usable products like pretrol from crude oil and pure metal from metal ores which are reduced
53
Risks and Good things about mining metal ores
* Useful products can be made
* Provides local ppl with jobs and brings money to area
* Bad for environment - uses lots of energy, scars landscape, destroys habitats, produces lots of waste
54
What is sustainable development?
Takes in account of the needs of present society while not damaging the lives of future gens
55
One way of reducing the use of finite resources
PPL to use less
56
What can chemists do to improve sustainibility?
* They can develop and adapt processes that use lower amounts of finite resources and reduce damage to environemnt
* EG theyy have developed catalysts to reduce amount of energy needed for certain industrial processes
57
Ways to increase copper supply
* Bioleaching
* Phytomining
58
What is phytomining?
* Plants grown in soil that contains copper
* Plants absorb copper and they concentrate it in their tissue
* Plants are harvested/burned
* Ash contains high conc of copper
* Ash dissolves in acid to produce a solution of copper compound
* Can be extracted by electrolysis or displacement using scrap iron (cheap and more reactive)
59
What is bioleaching?
* Bacteria mixed with low grade ore
* Bacteria carry out chemical reactions and produce a solution called a leachate
* Leachate contains wanted metal compound
60
One way to improve copper sustainability
Extracting it from low-grade ores (not lots of copper)
61
Disadvantages and advantages of phytomining and bioleaching compared to traditional methods
* Smaller impact (damage)
* Slow
* Trad methods are damaging to environment
* No digging, transporting, disposing large amounts of rock
62
Why is recycling metals good?
* Uses less energy than it is needed to mine and extract new metals
* Conserves finite amount of each metal on earth
* Cuts down amount of waste in landfill
63
How are metals recycled?
Melting them
Then Casting them into the shape of new product
64
Can glass bottles be reused?
Yes without reshaping
65
What happens to glass before it's recycled?
Glass is separated by colour and chemical composition
66
How is glass recycled?
* Crushed and melted to be reshape for use in glass products like jars
* Diff purpose too like insulating glass wool for wall insulation in homes
67
Problem with recycling metals give an example
* Metals need to be separated before recycled however this depends on the properties of the final product
* Eg. Scrap steel can be added to iron from a blast furnace - this reduces amount of iron needed to extract from iron ore
68
What is a LCA?
Life Cycle Assessment: looks at every stage of a product's life to assess the impact it would have on the environment
69
Stages in LCA
1. Getting raw materials
2. Manufacturing and packaging
3. Using the product
4. Product disposal
70
Getting raw materials (LCA)
* Can damage the local environment
* Pollution due to amount of energy needed to extract
* Large amounts of energy for raw materials to be processed to extract desired materials
71
Manufactruing and Packaging (LCA)
* Lots of energy resoucres used = lots of pollution eg harmful fumes like carbon monoxide, hydrogen chloride
* Think about any waste products and how to dispose of them
* Some waste can be turned into other useful chemicals
72
Using the product (LCA)
* Damage environement - burning fuels = GG gases
* Fertilisers can leach into streams/rivers and damage ecosystems
* How long a product is used for/ how many uses, lots of energy for ages = good for long run
73
Product disposal (LCA)
* Many disposed of in landfills
* Takes up space and pollutes land/water
* Energy used to transport it to landfill, pollutants released to atmos.
* Products might be incinerated (burnt) = air pollution
74
LCA for plastic bags
* Raw material = crude oil - non-renewable
* Extracting crude oil can harm habitats eg oil leak
* Chemically processed (lots of energy needed + releases waste products) -Compounds needed to make plastic extracted by fractional distillation, cracking, polymerisation. Waste is reduced as other fractions of crude oil have other uses
* Can be reused - multiple uses like bin liners - strong
* Recyclable not biodegradable - litter, fill up landfills
75
LCA for paper bags
* Raw material = timber - trees are renewable
* Felling trees for wood is destructive for habitats
* Chemically processed (lots of energy needed + releases waste products)
* Lots of water needed to make paper
* Pupled timber is processed using lots of energy - lots of waste made
* Used once, weak
* Biodegrable, non-toxic, recyclable
* Heavier than plastic bags - more energy for transportation
76
LCA plastic vs paper bags
plastic bags non biodegrable however they take less energy to make, longer lifespan so may be less harmful to environment
77
Probs of LCA
* Difficult to compare diff harms eg lung disease vs global warming
* Difficut ro gather all required data about each step
* companies can manipulate LCAs to look more favourable
* can be biased eg to support claims by advertisers
78
what is potable water?
Water thats been treated or naturally safe for humans to drink, not pure, contains lots of other dissolved substances
essential for life
79
what does pure water contain?
only H20 molecules, ph 7
80
how can we make sure that potable water is safe?
* levels of dissolved salts arent too high
* has a pH between 6.5 and 8.5
* No bacteria or microbes
81
In the UK, what provides most of our potable water?
Rain water because its fresh water ( doesnt have much dissolved in it)
82
What 2 places can we collect water when it rains?
* Collect as surface water (lakes, rivers)
* Groundwater (in rocks called aquifiers that trap water underground)
83
Processes to treat fresh water sources so its safe in order
1. Filtration
2. Sterilisation
84
filteration
* Wire mesh screens out large twigs
* Gravel and sand beds filter out any solid bits
85
sterilisation
* water sterilised to kill harmful bacteria/microbes
* Done by bubbling chlorine gas through it
* Or using ozone or uv light
86
What is used instead of rain water in hot countries?
Seawater thats treated by desalination to provide potable water
87
What can be used to desalinate sea water?
* Distillation
* Or processes that use membranes like reverse osmosis
88
# Practical 8
How can you test and distil water in a lab?
1. **Test pH of water using pH meter** - if ph is too low or high, neutralise it with a titration. don't use an indicator because it will **contaminate the water**
2. **Test for presence of sodium chloride** - **flame test** on small sample, if sodium ions are present, flame will turn yellow.
3. **Test for presence of sodium chloride** - **add few drops of dilute nitric acid and few drops of silver nitrate solution** - if chlrodie ions are present, white precipitate will form
4. To distill, pour salty water into a distillation aparatus. Heat flask from below using BB. Water will boill and form steam, leaving dissolved salts in flask.
5. Steam will condense back to liquid water in the condesnor and can be collected
6. Retest distilled water for sodium chloride (flame test + silver nitrate solution + dilute nitric acid)
7. Retest pH with pH meter so pH = 7
89
Reverse osmosis
1. Salty water passed through a membrane that only allows water molecules to pass
2. Ions and larger molecules are trapped by membrane so separated from H20
90
Probs with distillation and reverse osmosis
* Loads of energy - expensive
* Not practical for producing large quantities of h20
91
Uses of water
* Showers
* Toilet
* Washing-up/ clothes
* Agriculture
92
What happens to the water when it is flushed?
Goes to the sewers and towards the sewage treatment plants
93
What water waste does agriculture produce
* Nutrient run-off from fields
* Slurry from animal farms
94
Sewage treatment process
1. Sewage is **screened** by passing through a mesh - removes large bits of material and grit
2. Sewage is allowed to settle in a **settlement tanks/ sedimentation** tanks to **undergo sedimentation** - heaviier suspensed solids sink to bottom to produce **sludge** and lighter **effluent** floats on top
3. Sludge taken away and digested by anerobic bacteria to produce biogas which is burned for electricity
4. Digested sludge can be used as fertilisers for farming
5. Air is bubbled through the liquid effluent - allows aerobic bacteria to multiply and break down any organic matter (+ other microbres in the water)
6. Liquid effluent is safely discharged into nearby sea or rivers
95
What does the liquid effluent contain?
large amounts of organic molecules and harmful microogrniams which has to be reduced before water is returned to the environment
96
What has to be done to water used by industry (making paper and chemicals) before it goes through general sewage treatment?
Harmful chemicals need to be removed
97
What is the easiest way to produce potable water? Drawbacks?
to use ground water from aquifers - usually safe to drink once it has been treated with chlorine
prob: aquifiers sometimes be polluted (with fertilisers from farms) - needs to be tested carefully
98
Sewage treatment vs desalination
* ST - more processes required than treating fresh water but uses less energy than D (+ D is expensive)
* Could be used as an alt for areas where water is scarce
* Prob: ppl dont like the idea of drinking water that was once sewage
99
What is the Haber process?
Used to make ammonia from hydrogen and nitrogen, can be used to produce nitrogen-based fertilisers
100
Equation of Haber process
N₂₍₉₎+ 3H₂₍₉₎ ⇌ 2NH₃₍₉₎ (+ heat)
nitrogen + hydrogen ⇌ ammonia
101
Why is the Haber process reaction well suited for an industrial scale?
Reactants arent too difficult or expensive to obtain
102
Where is nitrogen and hydrogen obtained for the Haber process?
* Nitrogen - from the **air** which is 78% nitrogen
* Hydrogen - comes from reacting methane (from a natural gas) with steam
103
Describe Haber Process steps
1. Reactant gases (H and N) passed over an iron catalyst - high temp (450) and a high pressure (200 atmospheres) are used
2. Since reaction is reversible, some of the ammonia produced converts back into H and N again. It eventually reaches a dynamic equilibrium
3. Ammonia is a gas but as it cools in the condensor it liquefies and is removed (to increase yield)
4. Unused H and N are recycled so nothing is wasted
5. Ammonia produces can be used to make ammonium nitrate - a v nitrogen-rich fertiliser
104
What kind of reaction is the forward reaction in the Haber process? So what kind of temperature would shift equlibrium to the right hand side?
Exothermic
Cool temp but makes reaction slow
105
Why do we use the compromise temperature of 450 in the Haber process?
* 450 is a compromise between % yield, rate of reaction and cost
* forward r is exothermic so reaction should be done at a low temp to get a high yield
* r are higher temps = faster, particles gain energy and collide
* High temps are expensive, so we cant use a very high temp
106
Probs with working at high pressures in the Haber process?
Expensive and dangerous so thats why its at 200 atmospheres
107
What does the iron catalyst do in the haber process?
* Increase rate of reaction
* Has no effect on the position of the equilibirum/ yield
108
Why are formulated fertilisers better than manure (farmers used to use this to fertilise fields)
* More widely availible
* Easier to use
* Dont smell
* Have enough of each nutrient so more crops can be grown
109
3 essential elements in fertilisers?
* Nitrogen
* Phosphurus
* Potassium
110
Why might the 3 essential elements be missing in the soil?
Used up by a previous crop
111
What do fertilisers do? Give an eg
* Replace missing elements from soil or provide more of them
* Increases crop yield, crops grow faster and bigger
* Eg. they add more N to plant proteins, makes plants grow faster - increases productivity
112
What are NPK fertilisers?
* Formulations containing salts of nitrogen, phosphurus and potassium in the right percentages of the elements
113
What is the main compound of nitrogen in NPK fertilisers? How is it made?
**Ammonium nitrate.**
* Use **ammonia** produced from Haber process and react it with **oxygen and water** to make **nitric acid**
* Ammonia + oxygen + water -> nitric acid
* React **nitric acid** with more **ammonia** to make **ammonium nitrate**
* Nitric acid + ammonia -> ammonium nitrate
114
Where does the potassium in NPK fertilisers come from>
* Potassium chloride can be mined
* Potassium sulphate can be mined
* Phosphate rock can be mined but the phosphate salts inside are insoluble so plants cant use them as nutrients
* So react phospahte rock with acids = soluble phosphates
115
What acids can you react phosphate rock with to make it soluble?
* nitric acid = phosphuric acid + calcium nitrate
* sulfuric acid = calcium sulfate + calcium phosphate (mixt = single superphosphate)
* phosphuric acid = calcium phosphate (triple superphosphate)
116
How would you produce ammonium nitrate in a school lab?
* Use dilute solutions of ammonia + nitric acid - makes it safe
* Produce crystals using water bath a BB - requies lots of heat energy (slow)
* Only small amount of ammonium nitrate in one go - called a batch process
| titration and crytsalliation used
117
How would you produce ammonium nitrate in the industry?
* Ammonia used as a gas, nitric acid is concentrated - more dangerous as reaction is v exothermic. Heat produced has to be safely removed. Heat used in later stages
* Heat from earlier is for evaporation of water to make a v concentrate AN product
* Chemical prdocued by a continous process - l
| giant vats are used
118
Why is desalination expensive?
High energy requirement
119
How to test for pure water?
Dertemine BP, should be fixed temp at 100 C, if impure it will boil at a temp over 100C
120
Why is it more difficult to produce drinking water from waste water than from lakes?
* More processes
* because it has more ogranic matter
* more microbes
* more toxic chemicals
121
2 methods to show presence of dissolved solids in a sample of water
* Evaporate all water from sample
* Measure samples boiling point
122
Why is sewage sludge used as a fertiliser?
* Increased demand for food
* conserves energy - more sustainable
* landfill space running out
* increased demand for organic fertiliser
123
Why isnt phytomining used a lot?
* Slow
* Land not avaiblible
* New technology
* high grade ores still availible
124
What metal is toxic?
Lead
125
Why isnt solar used as much as burning FF?
* Relys on the sun - nightime - no electrrcity
* Lack of space
126
Effects on global warming on environment
* Sulfure dioxide - acid rain - damage to buildings and trees - respiratory issues in humans
* Carbon monoxide - toxic
* Melting icebergs - flooding
* Droughts, famine
127
Are alloys malleable?
* No
128
Name 3 barrier methods
* Oiling
* Painting
* Electroplating
129
Benefits of relying on fresh water
* easy to access
* replaced freq
130
What type of reaction is the Haber process?
Reversible
131
Why is a pressure of 200 atmospheres used in the Haber process
* compromise between % yield, cost and rate of reaction
* fewer molecules of product so higher pressure will result in a larger yield (equilibrium to the right - more products)
* faster at higher pressure - more collisions + energy
* expensive so we cant use very high pressure
132
How is triple superphosphate made?
| compound useful
phosphate rock + phosphoric acid
133
What can ammonia be used to manufacture?
* Ammonium salts
* nitric acid
134
What compounds are obtained by mining? Which can't directly be used as a fertiliser?
* Mining: potassium chloride, potassium sulfate, phosphate rock
* phosphate rock cant be used directly (insoluble) - treat it with nitric or sulfuric acid to produce soluble salts
135
How is phosphate rock treated to be used as a fertiliser?
nitric or sulfuric acid to produce soluble salts that can be used as fertilisers
136
What is a formulation
* mixture made from a specific raito of chemicals
* ensure that product has required proporties
137
What do plant fertilisers do?
provide minerals ions needed by plants
138
Reasons why recycling is better tha n extracting
* recycling uses less energy
* recycling reduces waste
* copper ores are finite
* recycling conserves copper ores
* mining cause environmental impacts
139
How would you test for presence of dissolved solids in water?
* evaporate all water from sample
* measure samples boiling point
140
What temp and pressure is use in the Haber process?
450
200 atm
141
How could you show that filtered water has dissolved salts without using a chemical test?
leave to evaporate in evaporating basin
there will be crystals
142
Conditions for Haber process
* Passed over iron catalyst
* 450 C
* 200 atmospheres pressure
143
Where does hydrogen come from for the Haber process?
* natural gas
144
From looking at the haver process equation, how can you tell there is a high atom economy?
the only product is ammoina
145
How is ammonia separated from the haber process?
it is cooled then condenses whilst n and h are recycled
146
what is sterilised from sewage water?
microbes
147
When filtering water,why arent ions like sodium and chlorine affected?
Because they can pass through as they are in solution
148
what is meant by pure?
natrual state of water
149
What if you wanted to recycle copper and if you dont remove the plastic inside?
It would be impure if you didnt separate it
