Topic 10-Using Rescouces Flashcards
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What are cermaics?
Non metal solids with high melting point
What is clay?
●Soft material - can be moulded
●Fired at high temperature-hardens to form clay ceramic
What is clay used for?
Pottery and bricks
Name 3 properties of glass
●Generally transparent
●moulded when hot
●brittle when thin
What is soda lime glass made from?
It’s made from heating a mixture of limestone, sand and sodium carbonate and leaving to cool
What is Borosilicate glass made from?
Mixture of sand and boron trioxide. It has a higher melting point then soda lime glass.
What is a composite?
●One materials EMBEDDED in another, fibres of material (reinforcement) are surrounded by a matrix acting as a binder
What is fibre glass made from?
Glass embedded in matrix of polymer.
What are the properties and uses of fibre glass?
●low density
●very strong
Makes: skis, boats and surfboards
What is carbon fibre made from?
Made from polymer matrix, reinforcement is carbon atoms chains or carbon nanotubes.
What are the properties and uses of carbon fibre?
●strong
●light
Used for: aerospace and sport car manufacture
What’s concrete made from?
Made from aggregate (sand and gravel) embedded on cement.
What are the properties and uses of concrete?
●strong
Used for: building materials - skatepark
What is wood made from?
Natural composite of cellulose fibres held by organic polymer matrix.
How is low density poly(ethene) made?
●Moderate temperature
●high pressure
●Catalyst
Makes:Bags, bottles
How is high density poly(ethene) made?
●lower temperature
●pressure
●different catalyst
It’s rigged so used for: water tank, drain pipe
What does Thermosoftening polymers contain?
Individual polymer chains entwined together, with WEAK forces so you can MELT and REMOULD them.
What does Thermosetting polymers contain?
Monomers that form cross-links between polymer chains-solid structure. They are STRONG, HARD and RIGID.
What are general properties of ceramics?
●insulators
●Brittle
●stiff
What are general properties of polymers?
●insulators
●flexible
●easily moulded
Used in: Clothing, insulation in electrics
What are the properties of a metal?
●malleable ●good conductors ●Ductile ●shiny ●stiff Used in: wires, car body, cutlery
What are the alloys bronze and brass made from?
BRONZE: Copper + tin (medals, ornaments)
BRASS:Copper + Zinc (lowfriction-water taps)
What’s the formula for when iron rusts?
Iron + oxygen + water –> Hydrated iron(iii) oxide
Can a whole iron object corrode?
Yes, the exposed layer flakes of, exposing more iron till eventually it all flakes away!
Can aluminum corrode all away?
No, aluminum oxidises so it doesn’t flake away acting as a protective layer.
How do you prevent rust?
●Paint/coat with plastic
●Electroplating-(electrolysis reduce metal ions on iron electrode)
●oiling/greasing
●galvanised- spray with Zinc, if zinc is scratched off Zinc around site of scratch works as a SACRIFICED metal
What replaced the rubber material from tree sap?
Man made polymers used in tyres.
How does agriculture improve crops?
Enhance natrual conditions - fertilisers
What is a renewable resource?
Reform at a rate faster then/same as we use them. Like timber which only take a few years to grow.
What is a finite resource?
Can’t form quick enough to replace what’s used. Like fossil fuels, nuclear fuels, ores
What’s the risk of extracting finite resources?
●uses lots of energy
●scars landscape
●produces lots of waste
●destroy habitats
What are chemist doing to improve sustainability?
Develop and adapt processes that LOWER amount of finite resources and reduce damage to environment.
Example:Catalyst which reduce energy needed for industrial processes.
What is bioleaching?
●Bacteria convert copper compound in ore to soluble copper compound, seperating copper from ore.
● Leachate produced contains coper ions extracted by electrolysis or displacement with more reactive metal
What is phytomining?
●Growing plants in copper rich soil.
●Copper builds up in leaf
●plant harvested dried and burned in furnace
●ash produce has copper ions whcih can be extracted (electrolysis/displacement)
Should you recycle?
Yes, glass and metal
What’s the life cycle of a product?
●get Raw materials-damage environment
●manufacture and package-pollution
●use product
●Product disposal-pollute
What’s a problem with life cycle assessment?
●hard to give numerical value of pollutant
●can be bias
●shows only some impacts if product
What is potable water?
Water you can drink as it’s been safely treated.
Is potable water pure?
NO. Contains dissolved substances.
It must be: low in dissolved salts, ph 6.5-8.8, no bacteria
Where does water collect as when it rains?
●surface water - lakes, reservoir, river
●groundwater - rock called aquifers underground
Hoe are fresh water sources treated?
●filteration -wire mesh -gravel and sand bed ●sterilisation -kill bacteria and microbes by bubbling chlorine gas or use ozone or UV light
How do dry countries get potable water?
●Delalination of sea water by distillation
●or use membranes which only allow water through (reverse osmosis)
What are negatives of distillation And reverse osmosis?
●lots of energy
●expensive
●not practical for large amounts of water
Where does waste water come from?
●toilet and bath
●washing up
●nutrient run off from field and slurry from animal farm
How do you test and destill water in a lab?
●Test PH of water with PH meter (if too low or high use titration)
●yellow flame test for sodium ion
●dilute notice acid and silver nitrate solution make white precipitate in presence of chloride ions
●regualr distillation process learnt in topic 1
Explain the 6 stages of sewage treatment.
- Screening-remove large bits
2 . Sedimentation-heavy solids sink to bottom of settlement tank producing sludge, light effluent floats up
- effluent removed by biological aerobic digestion. Air pumped through water encourage bacteria to break down matter
- sludge at bottom of tank removed and Brocken down by ANAEROBIC digestion.
- methane gas released used as energy, rest of sludge is used as fertilisers
- toxic waste water may need extra chemicals, UV radiation or membranes.
What is the equation for the Haber Process?
Nitrogen + hydrogen –> Ammonia (+heat)
N2 + 3H2–>2NH3 (+heat)
What percent of the air is nitrogen?
78%
Where do they get the hydrogen for the harber process?
Reacting methane (from natural gas) with steam to form hydrogen and carbon dioxide.
Name the 3 basic steps in the Haber process.
- N and H passed over iron catalyst. High temperature and and pressure
- Some ammonia produce gets converted back to H and N (reversible reaction) Eventually reaches dynamic equilibrium
- Ammonia liquifies in condenser and is removed. Unused H and N are recycled back in process
What is ammonia used for?
Ammonium nitrate a rich in nitrogen fertiliser.
What is the forward reaction in the Haber process?
Exothermic.
How would increasing increasing the temperature in the Haber process effect the yield of ammonia?
●Forward reaction is exothermic
●so it tries to reduce temperature so it shifts to the left
●so the yield of ammonia would be less
Visa versa
Why is too low of temperature bad for the Haber process?
Rate of reaction is slower.
What is the best temperature for the Haber process?
450℃ is the best compromise.
If pressure increases in the Haber process how does this effect the yield?
●the reaction will try to decrease pressure
●Equillibrium will shift to the right as that’s the side with the fewer molecules (2 compared to 4)
●right side is the side with ammonia so ammonia yield increases
Visa Versa
What’s the optimum pressure for the Haber process?
200 atmosphere operating pressure. Not to dangerous or expensive but rte of reaction is still efficient.
Why are formulated fertilisers better then the days when farmers used manure?
●widely available
●easy to use
●just enough of each nutrient so more crops can grow
What are the 3 essential elements in fertilisers?
●nitrogen
●phosphorous
●Pottasium
How do fertilisers help plants?
●replace missing elements in ground
●provide more elements
So fertilisers improve productivity as plant grows faster
What is the formula for ammonium nitrate?
Ammonia + Nitric acid —> ammonium nitrate
NH3(aq) + NHO3 —>NH4NO3
Where does potassium come from?
Potassium chloride and potassium sulphate is mined.
Where does phosphate come from?
●it comes from phosphate rock but it’s insoluble
So…
●it reacts with acids to produce soluble
phosphate
