Topic 10 - Using Resources Flashcards
(36 cards)
1
Q
What are ceramics?
A
ceramics are non-metal solids with high melting popints - arent made from carbon-based compounds
2
Q
Clay ceramics?
A
- when fired at high temperatures - hardens to form clay ceramic
- ability to be moulded when wet and harden - ideal in pottery and bricks
3
Q
Glass ceramics?
A
- glass can be moulded when hot and can be brittle when thin
- most glass soda-lime glass - made by heating mixture of limestone, sand and sodium carbonate until it melts
- when mixture cools - comes out as glass
4
Q
What are composities?
A
made of one material embedded into another
5
Q
Fibreglass?
A
- consists of fibres of glass embedded into matrix made of polymer (plastic)
- low density like plastic but very strong like glass
6
Q
Carbon fibre?
A
- have polymer matrix
- made from large chains of carbon atoms bonded together or carbon nanotubes
7
Q
LD and HD polyethene use?
A
- LD polyethe made from ethene at moderate temperature under high pressure
- flexible and used for bags and bottles
- HD polyethene made from ethene at lower temperature and pressure with catalyst
- more rigid - used for wataer tanks and drainpipes
8
Q
Thermosoftening polymers?
A
- contain individual polymer chains entwined together with weak forces between chains
- can melt these plastics and remould them
9
Q
Thermosetting polymers?
A
- contain monomers that form cross-links between polymer chains - hold chains in solid structure
- dont soften when heated - hard and rigid
10
Q
What is corrosion?
A
where metals react with substances in environment - gradually destroyed
11
Q
What is rust?
A
rust is ONLY corrosion of iron
12
Q
Rust equation?
A
iron + oxygen + water –> hydrated iron (III) oxide
13
Q
Aluminium corrosion?
A
- corrodes when exposed to air - aluminium oxide doesnt flake away
- forms nice protective layer - sticks firmly to aluminium below - stops further reactions taking place
14
Q
What is needed for iron to rust?
A
air and water
15
Q
Ways to prevent rusting?
A
- coat iron with barrier to keep out water and oyxgen e.g. painting/electroplating/oiling and greasing
- sacrificial method - place more reactive metal with iron - water and oxygen react with sacrifical metal instead
16
Q
What is bioleaching?
A
- bacteria used to convert copper compounds in ore into soluble copper compounds - separating out copper from ore in process
- leachate contains copper ions which can be extracted via electrolysis
17
Q
What is phytomining?
A
- plants grown in soil that contains copper - absorbing metal compound through roots
- plants harvest and dried - burned in furnace - metal extracted from ash - copper extracted by electrolysis or displacement with scrap iron
18
Q
Advantages of using bioleaching and phytomining for metal extraction?
A
- environmentally friendly – cause less habitat destruction compared to traditional mining
- lower energy consumption – requires less energy than traditional mining and smelting
- carbon reduction – phytomining absorbs CO₂ during plant growth - reduces greenhouse gases
- more sustainable – allows metal extraction from low-grade ores - reducing reliance on high-grade ores
19
Q
Disadvantages of using bioleaching and phytomining for metal extraction?
A
- low efficiency – yield of extracted metal lower compared to conventional mining
- slow process – bioleaching and phytomining take years to produce usable metals
- bioleaching can produce harmful leachate solutions
- limited application – phytomining only works with certain types of metals and specific plant species
20
Q
Why is recycling metals important?
A
- mining and extracting metals takes lot of energy - comes from burning fossil fuels
- recycling uses much less energy than needed to mine and extract
21
Q
What is potable water?
A
water that has been treated and is safe for humans to drink
22
Q
How are fresh water sources treated?
A
- filtration - wire mesh screens out large twigs etc - gravel and sand beds filter out any other solid bits
- sterilisation - water is sterilised to kill any harmful bacteria or microbes - done by bubbling chlorine gas through it or by using ozone or ultraviolet light
23
Q
Desalination of salt water?
A
- distillation used to desalinate water
- first test pH of water using pH meter - if pH is too high or low - neutralise it - do this via titration - use pH meter to determine pH rather than indicator - wont contaminate water
- test water for presence of sodium chlroide - flame test to test for sodium ions - flame turns yellow if sodium ions present - test for chloride ions - take sample of water - add dilute nitric acid followed by silver nitrate solution - white precipitate forms if chloride ions present
- distil water - heat flask from below - water will boil and form steam - leaving dissolved salts in flask - steam condenses back into liquid water- collected
- retest distilled water for sodium chloride to check it has been removed - retest pH of water
24
Q
What sources do waste water come from?
A
- agricultural systems produce a lot of waste water including nutrient runoff
- industrial processes such as haber process produce lots of waste water
25
Sewage treatment?
- before being treated - sewage screened - involves removing large bits of material as well as grit
- undergoes sedimentation - heavier suspended solids sink to bottom to produce sludge while lighter effluent floats on top
- effluent in settlement tank removed and treated by biological aerobic digestion - air is pumped through water to encourage aerobic bacteria to break down any organic matter - including other microbes in water
- slude from bottom of settlement tank removed and transferred into large tanks - gets broken down by bacteria in process called anaerobic digestion
- anaerobic digestion breaks down organic matter in sludge - releasing methane gas in process - methane gas used as energy source - remaining digested waste used as a fertiliser
26
How is the haber process used?
- haber process used to make ammonia from hydrogen and nitrogen using following reaction:
- nitrogen + hydrogen --><--- ammonia
27
How does the haber process work?
- nitrogen obtained easily by air - 78% nitrogen
- hydrogen mainly comes from reacting methane with steam to form hydrogen and CO2
- reactant gases passed over iron catalyst - high temperature (450°C) and high pressure (200 atmospheres)
- as reaction is reversible - some of ammonia produced converted back into hydrogen and nitrogen - eventually reaches dynamic equilibtrium
- ammonia formed as gas - cools in condensor and liquifies - unused hydrogen and nitrogen recycled
- ammonia produced can be used to make ammonium nitrate - very nitrogen-rich fertiliser
28
Ideal conditions for haber process? Temperature
- forward reaction in haber process is exothermic - increasing temperature moves equilibrium wrong way - away from ammonia and towards nitrogen and hydrogen - yield of ammonia greater at lower temp
- lower temps mean slower rate of reaction - equilibrium reached more slowly
- 450°C compromise between maximium yield and speed of reaction
29
Ideal conditions for haber process? Pressure
- higher pressures move position of equilibrium toward products since four molecules of gas on left for every two on the right - increasing pressure maximises yield - also increases rate of reaction
- pressure set as high as possible without making process too expensive to or dangerous to build and maintain
30
What do NPK fertilisers supply plants with?
- nitrogen, phosphorus and potassium
- if plants dont get enough of these elements their growth and life processes are affected
- fertilisers replace these missing elements or provide more of them - help to increase crop yield
31
How is ammonia used to produce nitrogen-containing compounds?
- ammonia can be reacted with oxygen and water in series of reactions to make nitric acid
- ammonia + nitric acid react together to produce ammonium nitrate - an especially good compound to use in a fertiliser because it has nitrogen from two sources - ammonia and nitric acid
32
How is ammonium nitrate made in industry?
- reaction carried out in giant vats at high concentrations - results in very exothermic reaction
- heat released used to evaporate water from mixture to make very concentrated ammonium nitrate product
33
How is ammonium nitrate made in the lab?
- reaction carried out on much smaller scale by titration and crystalisation
- reactants are at much lower concentration than industry - less heat produced - safer for person to carry out
- after titration - mixture needs to be crystallised to give pure ammonium nitrate crystals - very slow
34
How are phosophate and potassium sourced from mined compounds?
- potassium chloride and potassium sulphate can be mined - used as source of potassium
- phosphate rock also mined - phosphate salts in rock insoluble - cant be used as nutrients by plants
35
How can phosphate rock react to produce soluble phosphates?
- reaction with nitric acid - phosphuric acid and calcium nitrate
- reaction with sulfuric acid - calcium sulfate and calcium phosphate - single superphosphate
- reaction wth phosphoric acid - calcium phosphate - triple superphosphate
36
Life cycle assessments?
- Stage 1 - getting the raw materials
- Stage 2 - manufacturing and packaging
- Stage 3 - using the product
- Stage 4 - product disposal
