Using Resources Flashcards
what do humans use the earths resources for
to provide warmth, shelter, food and transport
what do natural resources provide
food
timber
clothing
fuels
why are finite resources from the earth, oceans and atmosphere processed
to provide energy and materials
what does chemistry play an important role in
improving agricultural and industrial processes to provide new products
sustainable development
what is sustainable development
development that meets the needs of current generations without compromising the ability of future generations to meet their own needs
what are renewable energy resources
sources of power that quickly replenish themselves and can be used again
only includes plants or wood if they continue to be replanted
what are finite resources
resources with a limited supply that will eventually run out
what is potable water
water of a suitable quality which is essential for life so is safe to drink
what does water need for humans
sufficiently low amounts of dissolved salts and microbes
potable water production process
1 filtered so leaves stones and large material is removed
2 water moves and only sediment settles at the bottom of the tank
3 add aluminium sulphate making the particles clump together and settles at the bottom
4 water is passed through fine sand and gravel to remove more particles
5 sterilisation occurs to kill microbes using chlorine or uv light
6 check the ph and adjust it if needed
how do you purify salty water
desalination
desalination by distillation
1- salty water is evaporated as sea water is heated
2- water is cooled and condensed
3- salt is left in the first tank
4- creates pure freshwater
desalination by reverse osmosis
1-using high pressure, salty water is forced through a semi permeable membrane
2- the salt is removed and the water moves through
disadvantages of desalination
both methods are very expensive
sewage water treatment process
1 sewage arrives to the pumping station and large objects are filtered from the water through a mesh screen
2- primary sedimentation -large paddles swirl the water and solids sink and are collected at the bottom
3- biological treatment- bacteria feed aerobically on organic matter and kill harmful bacteria
4- secondary sedimentation- good bacteria are removed here
5- water is sterilised using chlorine, ozone or uv light
6- it is pumped into seas and rivers
7- waste is digested by anaerobic respiration in a biogas tank
what is the sewage leftover used for
fertiliser
biogas
solid fuel
landfill sites
to generate electricity
where is it cheapest and easiest to obtain potable water from
groundwater
wastewater
when is seawater easier to obtain potable water
for countries with little fresh water
production of biogases in a biogas tank
1 sewage waste containing organic matter goes into the slurry
2 carried out at temp between 35 and 55 degrees
3 in the digester microorganisms will respire anaerobically to produce biogas
4 any solid matter left is pumped out of the outlet and used as fertiliser
why are life cycle assessments carried out
to assess the environmental impact of a product through all stages of its life
what are the stages of the life cycle assessment
raw materials
manufacture
distribution
product use
disposal of the product
what does the raw materials stage of the LCA deduce
are they renewable/non renewable
where are they found
how far do they need to be transported
what does the manufacturing stage of the LCA deduce
what processes are needed for manufacture of the materials and the product
what does the distribution stage of the LCA deduce
the environmental impacts of transporting the product
how far it has to be transported
what does the product use stage of the LCA deduce
does it have an environmental impact
how long will it last
can it be reused or repurposed
what does the disposal of the product stage of the LCA deduce
can it be used in another way
is it biodegradable
is there a choice between landfill, incineration or recycling
raw materials stage of lca for a paper bag
the wood from the trees that is used to make the paper is not a finite resource
the logs need to be transported to a mill for processing
manufacture stage of lca of a paper bag
the trees are debarked and chipped into wood chips in a factory
the chips are cooked with chemicals to a pulp which is bleached to make it white and chlorine is added
distribution stage of LCA of a paper bag
the finished product is shipped around the world which has environmental impacts as the vehicles used to transport the goods will use fossil fuels
product use stage of lca of a paper bag
people use paper everyday
it is not often used very resourcefully
disposal of the product stage of the lca of a paper bag
paper once used can either go into landfill or it can go in the recycling to be made into new paper
raw materials stage of the lca of a plastic bag
oil needs to be extracted to create plastic bags which is a non renewable product
oil is a finite resource
manufacture stage of the lca of a plastic bag
oil undergoes a chemical reaction to turn it into a solid plastic
it is then blown into plastic bags
distribution stage of lca of a plastic bag
shipped all around the world which will have environmental impacts as more fossil fuels will be used
product use stage of lca of a plastic bag
plastic bags usually are only used once or twice before getting thrown away
disposal of the product stage of lca of a plastic bag
thousands of tonnes get sent to landfill where they cannot biodegrade and others can be recycled and will be turned back into bags or brand new items altogether
what is low grade copper ores
rock that has small amounts of copper in it
what are the methods of extracting copper
phytomining
bioleaching
what does phytomining use
plants
process of phytomining
plants are planted on low grade copper ores. they absorb copper ions from the soil by their roots. can grow plants on contaminated soil
the plants are burned which releases carbon dioxide. you are left with plant ash containing copper ions in copper oxide
we use electrolysis to extract the copper from the copper oxide
features of the phytomining process
slow process
can be made quicker by using fast growing plants
renewable source used
carbon neutral so plants take in co2 during photosynthesis which is released when burnt
what does bioleaching use
bacteria
process of bioleaching
the bacteria feed on low grade copper ores and produce a leachate
the leachate contains copper ions
we use electrolysis to extract the copper from the leachate
what is a leachate
a solution that passes through an organism
features of bioleaching
slow process
bacteria produces other toxins
how is copper extracted from copper rich ores
smelting
smelting process
heat copper carbonate a lot to make copper oxide and carbon dioxide
add sulphuric acid to the copper oxide to make copper sulphate solution
copper sulphate and iron are reacted to make iron sulphate and copper
or electrolysis is used to split into copper and oxygen
symbol equation for copper sulphate and iron reacting
CuSO4 + Fe —-> FeSO4 + Cu
what would you see when copper sulphate and iron react
a red - brown substance
how are nitrogen based fertilisers used
by plants for growth
by plants for making proteins
how do plants take up soluble nitrate ions
through their root hair cells
why do we need nitrogen based fertilisers
when we harvest crops nitrogen is removed
what is fixing nitrogen
gaseous nitrogen is turned into nitrogen compounds that can be absorbed in solution by plants
why is ammonia important
80% nitrogen in atmosphere
nitrogen gas is insoluble in water
plants need a soluble form
what is needed to make ammonia
nitrogen from the air
hydrogen from natural gas
what are nitrogen and hydrogen examples of
raw materials
haber process
1-nitrogen and hydroge are pumped through pipes
2- pressure is increased to 200 atmospheres (high pressure) at the compressor
3- pressurised gases are heated to 450 degrees and passes through a tank with iron catalyst beds
4- some nitrogen , hydrogen and ammonia leave the iron catalyst beds and enter the cooling tank
5- at the cooling tank mixture is cooled so ammonia liquefies and is removed
6- unreacted nitrogen and hydrogen are recycled and are re compressed and heated before returning to the reaction vessel
what is the reaction for making ammonia
reversible
balanced symbol equation for the haber process
N2 (g) + 3H2 (g) reversible reaction 2NH3 (g)
how is nitrogen extracted
fractional distillation
liquid air
what are conditions needed to extract nitrogen
needs high pressure pumps
-200 degrees
where is hydrogen extracted from
from natural gas (methane)
extracting hydrogen word equation
methane + steam –> hydrogen + carbon monoxide
conditions needed to extract hydrogen
needs a very high temperature
what is needed to make the maximum amount of ammonia
the reaction needs high pressure
what are the problems with very high pressure
lots of energy is needed to compress gases
expensive reaction vessels and pipes needed to avoid explosions
what is the compromise to reduce problems with very high pressure
use a lower 200 atmospheres pressure
impact of the compromise to reduce problems with very high pressure
gives a lower yield
but it reduced costs and is more safe
problems with low temperature in haber process
rate of reaction very slow because there are less frequent collisions
why do we use 450 degrees temp in haber process
good rates of reaction and make ammonia fast however less yield of ammonia
which three elements are essential to grow plants
nitrogen
phosphorous
potassium
what do npk fertilisers contain
compounds of nitrogen phosphorus and potassium
what are npk fertilisers
formulations of NPK salts containing appropriate percentages of the elements
industrial production of ammonium nitrate
ammonia added to giant vats containing highly concentrated nitric aid
results in a very exothermic reaction
heat released used to evaporate water from mixture to make a very concentrated ammonium nitrate product
ammonium nitrate production in the lab
smaller scale using titration and crystallisation
ammonia solution used and reactants at a lower concentration than in industry so less heat is produced and safer to carry out
after titration mixture needs to be crystallised but its slow
why do we have to react phosphate rock with acids
phosphate rock can’t be used directly as fertiliser
what is produced when nitric acid reacts wit phosphate rock
phosphoric acid and calcium nitrate
what is produced when sulfuric acid reacts with phosphate rock
calcium sulfate and calcium phosphate (known as single superphosphate)
what is produced when phosphoric acid reacts with phosphate rock
calcium phosphate ( product can be called triple superphosphate)
what can ammonia be used to manufacture
ammonium salts and nitric acid
why is salt ammonium nitrate a good fertiliser
high proportion of nitrogen per unit mass
how are ammonia nitrate salts formed
ammonia + nitric acid
what is produced when phosphate rock reacts with types of acids
soluble salts that can be used as fertilisers
what is corrosion
the destruction of materials by chemical reactions with substances in the environment
what happens during corrosion
metals react with oxygen to form a metal oxide layer
when the metal oxide forms we say the metal has corroded
corrosion can be protective
what is rusting
a form of corrosion that is not protective
which substance rusts
iron
when does iron rust
if in contact with oxygen and water
it forms a hydrated iron III oxide
how does creating a barrier prevent rusting
iron is painted or coated in plastic or oiled or greased
keeps oxygen and water away from iron and is decorative
how does the sacrificial method prevent rusting
coating iron in a more reactive metal eg zinc (called galvanising)
water and oxygen react with this metal instead of the iron
what happens when rusting occurs
the mass will increase as it now has the mass of oxygen in the compound made
which kind of materials are ceramics
clay
glass
features of clay
ceramic
soft material
shaped and then heated in a furnace
used for making pottery and bricks
features of glass
most is soda lime glass made by heating sand sodium carbonate and limestone
other type of glass is borosilicate glass made from heating sand and boron trioxide
borosilicate glass has a higher melting point than soda lime glass
what are most composites made of
two materials, a matrix or binder surrounding and binding together fibres or fragments of the other material called reinforcement
examples of composites
wood
fibreglass
nanotubes
concrete
how is wood a composite
made of cellulose fibres as reinforcement
held together by lignin, an organic polymer as a matrix
it gives trees strength
how is fibreglass a composite
glass fibres as the reinforcement
held together by polymers as the matrix
has a low density so used for surfboards
good insulator so used for roof insulation
how are nanotubes composites
carbon nanotubes as reinforcement
held together by polymers as matrix
strong and light and used for sports equipments and aircraft’s
how is concrete a composite
aggregate of sand and gravel as reinforcement
held together by cement
strong and rigid so used as building material
what do properties of polymers depend on
the monomer used
conditions used to make it
what happens if you use the same monomer but different conditions
make two different types of polymer
how is low density polyethene made
heating ethene to about 200 degrees under high pressure
what are lpdes used for
flexible so used for bags and bottles
how is high density polyethene made
heating ethene at a lower temperature and pressure with a catalyst
what is hdpe used for
more rigid and used for harder plastics like water tanks or drain pipes
what are the two types of polymers
thermosoftening plastics
thermosetting plastics
features of thermosoftening plastics
made of lots of individual polymer chains tangled together
there are weak forces between the chains
plastics are set as one shape and wont melt, when they are reheated they soften and can be reshaped
features of thermosetting plastics
made of lots of individual polymer chains held together by strong cross links (ionic or covalent bonds)
chains are closer together and have a higher density as more atoms are in a unit of volume
these plastics are set as one shape and won’t melt or be softened
