Topic 10 - Using Resources

Question 1

What are ceramics?

Answer 1

ceramics are non-metal solids with high melting popints - arent made from carbon-based compounds

Question 2

Clay ceramics?

Answer 2

• when fired at high temperatures - hardens to form clay ceramic
• ability to be moulded when wet and harden - ideal in pottery and bricks

Question 3

Glass ceramics?

Answer 3

• 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

Question 4

What are composities?

Answer 4

made of one material embedded into another

Question 5

Fibreglass?

Answer 5

• consists of fibres of glass embedded into matrix made of polymer (plastic)
• low density like plastic but very strong like glass

Question 6

Carbon fibre?

Answer 6

• have polymer matrix
• made from large chains of carbon atoms bonded together or carbon nanotubes

Question 7

LD and HD polyethene use?

Answer 7

• 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

Question 8

Thermosoftening polymers?

Answer 8

• contain individual polymer chains entwined together with weak forces between chains
• can melt these plastics and remould them

Question 9

Thermosetting polymers?

Answer 9

• contain monomers that form cross-links between polymer chains - hold chains in solid structure
• dont soften when heated - hard and rigid

Question 10

What is corrosion?

Answer 10

where metals react with substances in environment - gradually destroyed

Question 11

What is rust?

Answer 11

rust is ONLY corrosion of iron

Question 12

Rust equation?

Answer 12

iron + oxygen + water –> hydrated iron (III) oxide

Question 13

Aluminium corrosion?

Answer 13

• corrodes when exposed to air - aluminium oxide doesnt flake away
• forms nice protective layer - sticks firmly to aluminium below - stops further reactions taking place

Question 14

What is needed for iron to rust?

Answer 14

air and water

Question 15

Ways to prevent rusting?

Answer 15

• 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

Question 16

What is bioleaching?

Answer 16

• 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

Question 17

What is phytomining?

Answer 17

• 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

Question 18

Advantages of using bioleaching and phytomining for metal extraction?

Answer 18

• 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

Question 19

Disadvantages of using bioleaching and phytomining for metal extraction?

Answer 19

• 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

Question 20

Why is recycling metals important?

Answer 20

• mining and extracting metals takes lot of energy - comes from burning fossil fuels
• recycling uses much less energy than needed to mine and extract

Question 21

What is potable water?

Answer 21

water that has been treated and is safe for humans to drink

Question 22

How are fresh water sources treated?

Answer 22

• 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

Question 23

Desalination of salt water?

Answer 23

• 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

Question 24

What sources do waste water come from?

Answer 24

• agricultural systems produce a lot of waste water including nutrient runoff
• industrial processes such as haber process produce lots of waste water

Question 25

Sewage treatment?

Answer 25

- 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

Question 26

How is the haber process used?

Answer 26

- haber process used to make ammonia from hydrogen and nitrogen using following reaction: - nitrogen + hydrogen --><--- ammonia

Question 27

How does the haber process work?

Answer 27

- 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

Question 28

Ideal conditions for haber process? Temperature

Answer 28

- 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

Question 29

Ideal conditions for haber process? Pressure

Answer 29

- 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

Question 30

What do NPK fertilisers supply plants with?

Answer 30

- 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

Question 31

How is ammonia used to produce nitrogen-containing compounds?

Answer 31

- 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

Question 32

How is ammonium nitrate made in industry?

Answer 32

- 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

Question 33

How is ammonium nitrate made in the lab?

Answer 33

- 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

Question 34

How are phosophate and potassium sourced from mined compounds?

Answer 34

- 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

Question 35

How can phosphate rock react to produce soluble phosphates?

Answer 35

- 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

Question 36

Life cycle assessments?

Answer 36

- Stage 1 - getting the raw materials - Stage 2 - manufacturing and packaging - Stage 3 - using the product - Stage 4 - product disposal