Using resources Flashcards
what are ceramics
non metallic solids with high melting points that are not made from carbon based compounds
what are some general properties of ceramics
good insulators of heat and electrify and very brittle and stiff
what are clay ceramics
when clay is fired at a high temperature it hardens to form a cay ceramic. Ideal for making pottery and bricks
what are glass ceramics
glass can be moulded when hot and brittle when thin.
most glass is a soda lime glass ( made by heating limestone, sand and sodium carbonate until it melts and then it cools to become glass.
borosilicate glass has a higher melting point. its made in the same way as soda lime glass but using sand and boron trioxide
what are composites
one material embedded in another. fibres or fragments are surrounded by a matrix which acts as a binder
what are polymers
large molecules formed when small molecules ( monomers) join together.
held by strong covalent bonds in long chains
most insulators of heat and electricity and can be flexible
clothing, insulators and electrical items
what are two important things that influence the properties of a polymer
the monomers
conditions in which its made
how do the monomers effect the property of a polymer
they determine what type of force form between the polymer chains. e.g. if there are cross links or not
what are thermosoftening polymers
made of individual tangled chains of polymers. weak forces between the chains which mean they are flexible and can be melted and remoulded.
what are thermosetting polymers
cross links between polymer chains so doesn’t melt when heated, it chars instead. They are strong, hard and rigid
how do reaction conditions affect the properties of polymers
low density polyethene is made at 200 degrees under hp.
high density polyethene is made at a lower temp and pressure with a catalyst
what are alloys
mixtures of two or more metals or a metal and non metal
why do we use a lot of alloys
pure metals are often too soft because the layers of atoms slide over each other
why are alloys harder than most metals
different elements have different sized atoms so it will distort the layers of the metal atom making it harder for the layers to slide
why is most iron used to make steel
too soft and bendy
what is added to iron to make steel
carbon and sometimes other metals
give a use for both low carbon and high carbon steel
low - car bodies
high- bridges
what is added to make stainless steel
chromium and sometimes nickel
bronze
idk but i should
brass
alloy of copper and zinc gold like appearance more malleable than bronze good for application which require moving with low friction e.g. water taps and door fittings
gold alloys
used for jewellery cus pure gold is too soft
zinc, copper and silver can be used to harden gold
have slightly different colour to pure gold
aluminium alloys
low density
aircrafts
alloyed with small amounts of other metals to make it stronger as its too soft for aeroplanes
what is corrosion
when a metal is gradually destroyed by reacting with substances in the environment
what is the equation for iron rusting
iron + oxygen + water makes hydrated iron (iii) oxide
when aluminium corrodes, why doesn’t it get completely destroyed
the aluminium oxide doesn’t flake away so it leaves a protective layer
how do you experiment rusting
nail in boiling tube w water and it wont rust
just air it wont rust
water and air it will rust
how can creating a barrier prevent rust
painting a metal or coating w plastic
electroplating uses electrolysis to reduce metal ions onto an iron electrode. can be used to coat iron with a different metal that wont corrode
oiling or greasing
how can the sacrificial method be used to prevent rust
put more reactive metal w the one u want to protect so reaction will take place w that one
how is iron galvanized
spayed w a coating of zinc
what is sustainable development
takes account of need of present society while not damaging lives of future generations.
what 3 things need to be considered when extracting finite resources
social, economic and environmental effects
pros of reusing and recycling
less energy than required to extract material
why do we need new ways of extracting copper
supply of copper rich ores is limited
demand is high
traditional methods are expensive for low grade ores
how does bio leaching work
bacteria convert copper compounds into soluble copper compounds, separating the copper from the ore in the process.
the leachate contains copper ions which can be extracted by electrolysis or displacement reactions.
scrap iron is often used for displacement
how does phytomining work
growing plants in soil that contain copper
copper builds up in leaves
harvested, dried and burned in furnace
copper extracted from ash thro displacement/ electrolysis
pros of bio-leaching and phytomining
cheap smaller environmental impact require less energy low grade ores are not mined in same way so beneficial to habitats however they are slow
why is recycling important
less energy needed
so saves money
preserves finite resources
less landfill
how is glass recycled
separated by colour and chemical composition
crushed and melted to reshape
what do life cycle assessments do
asses the environmental impact of the entire lifetime of a product
what are the 4 stages of the lifetime of a product
getting raw material
manufacturing and packaging
using product
product disposal
at each stage of the LCA, what is considered
energy water and other resources pollution waste how the waste is disposed
pro and con of incineration
less waste goes to landfill
can generate electricity
air pollution
selective LCA
show only some of the impacts
can be biased
can be written to support claims of a companies
what is potable water
been treated or naturally safe for humans. can contain lots of other dissolved substances. pH between 6.5 and 8.5, salts are not too high and no dangerous bacteria
what is fresh water
not much dissolved in it. e.g. rainwater from lakes and reservoirs and groundwater
what treatment does fresh water go through
filtration - wire mesh, gravel and sand beds filter out solids
sterilization - bubbling chlorine gas through, using ozone or ultraviolet light
what is desalination
making sea water potable
done via reverse osmosis or distillation which is really expensive
how does reverse osmosis work
water passed through a membrane that traps ions and larger molecules
why is sewage treated
to remove organic matter nad harful microbes. instural waste water has to undergo additional stages of treatment
what is screening
removing large materials like plastic bags and grit sewage is treated
what is sedimentation in waste water treatment
after screening, swage stands in settlement tank where heavier solids sink to produce a sludge. (sedimentation)
what is aerobic digestion in waste water treatment
after sedimentation the effluent is treated by biological aerobic digestion where air is pumped through the water to encourage aerobic bacteria to break down any organic matter and microbes
what in anaerobic digestion in waste water treatment
slug removed from settlement tank and transferred to large tanks where its broken down by bacteria in anaerobic digestion. this releases methane which can be used as an energy source and remaining waste is used as a fertilizer
why would you get potable water from waste water
in areas where there isnt much water. it requires more processes but uses less energy than desalination of salt water. ppl dont like the idea of drinking water that used to be sewage
where does the nitrogen and hydrogen come from thats used in the haber process
nitrogen form air
hydrogen from reacting natral gas ( methane) with steam
or from crude oil
what is the symbol equation for the haber process
N”2 + 3H”2 2NH”3
what temp and preasure is used for the haber process
450
200atm
how is the ammonia gas extracted
cooled in a condenser and liquefied and then removed from reaction vessal
what catalyst is used in the haber process
iron
why should the temp be at 450 for haber
forward reaction is exothermic so increasing the temp will make the equilibrium shift the wrong way so yield is greater at lower temp.
lower temp = lower ror so 450 is a compromise
why is pressure 200atm in haber process
high pressure favours forward reaction so high pressure increases the yield
hp also increases ror
however hp means expensive plant
why is an iron catalyst used
make reaction go faster so reaches equilibrium faster. doesn’t change amount of products at equilibrium. high temp would be needed without them
what are the three main essential elements needed by plants
nitrogen, phosphorus and potassium
why do farmers use fertilizers
to replace missing elements or provide more of them because it helps crop yield as the crops can grow bigger and faster
what are NPK fertilizers
formulations containing salts of nitrogen, phosphorous and potassium in the right percentages
what other nitrogen containing compounds can be produced from ammonia
+ oxygen then water = nitric acid
+ acids = ammonium acids
+ nitric acid (HNO”3) = ammonium nitrate (NH”4NO”3)
why is ammonium nitrate a good component of fertiliser
high proportion of nitrogen per unit mass
how is ammonium nitrate made in industry
ammonia gas is added directly to giant vats containing highly concentrated nitric acid which results in very exothermic reaction. The heat released is used to evaporate water to make a very concentrated ammonium nitrate product
how is ammonium nitrate made in the lab
titration and crystallisation. much slower and lower concentration so less heat
phosphate rock cannot be used as a fertilizer. what can it be made into that can be used
+nitric acid = phosphoric acid and calcium nitrate
+ sulfuric acid = calcium sulphate and calcium phosphate
