Science - Chemistry - Using resources - C10 Flashcards
what are ceramics ?
non-metallic solids with high melting points that aren’t made from carbon based compounds
what are the properties of ceramics ?
good insulators of heat/electricity
brittle
stiff
what are the 2 types of ceramics ?
clay ceramics
glass
what is clay ?
a soft material when it is dug out of the ground so it can be moulded into different shapes
what happens when clay is fired at high temperatures ?
it hardens to form a clay ceramic
what is clay useful for ?
making pottery / bricks
what are properties of glass ?
generally transparent
moulded when hot
brittle
what is the most common type of glass ?
soda lime glass
how is soda lime glass made ?
by heating a mixture of limestone sand and sodium carbonate until it melts then cools
which glass has a higher melting point :
borosilicate glass
or
soda lime glass
borosilicate glass
how is borosilicate glass made ?
using a mixture of sand and boron trioxide
what are composites ?
made of one material embedded in another - fibres or fragments of a material are surrounded by a matrix acting as a binder
what does the properties of composites depend on ?
the matrix/binder and the reinforcement used to make them
what are the uses of composites ?
- wood
-fibreglass
-carbon fibre composites - concrete
how is wood made ?
cellulose fibres held together by lignin
give uses of wood ?
building material
give properties of wood
strong
versatile
attractive
what is fibreglass made of ?
fibres of glass embedded in a matrix polymer
give properties of fibreglass
low density
strong
what is fibreglass used for ?
skis
boats
surfboards
how are carbon fibre composites made ?
from carbon nanotubes or long chains of carbon atoms
give properties of carbon fibre composites
strong
light
what are carbon fibre composites used for ?
aerospace
sports car manufacturing
how is concrete made ?
from aggregate embedded in cement
give properties of concrete ?
strong
rigid
give uses of concrete
building material
what are polymers ?
large molecules formed when many small molecules called monomers join together
give properties of polymers ?
insulators of heat/electricity
flexible
easily moulded
give uses of polymers
clothes
insulators in electrical items
what are the 2 things which influence the properties of a polymer ?
the monomers its made from
the conditions under which it’s made
what do the monomers a polymer is made from decide ?
what type of forces form between the polymer chains
what are thermosoftening polymers ?
made of individual tangled chains of polymers
what are the properties of thermosoftening polymers ?
flexible
can be melted then remoulded
what kind of forces are between thermosoftening polymer chains ?
weak forces
what are thermosetting polymers ?
have cross links between their polymer chains
what happens to a thermosetting polymer when heated ?
it chars
what are the properties of thermosetting polymers ?
strong
hard
rigid
give an example of how reaction condition affects properties of polymers ?
- 2 types of poly(ethene) can be made :
Low density poly ethene
High density poly ethene
how is low density poly ethene made ?
by heating ethene to a moderate temperature at high pressure
what are the properties of low density poly ethene ?
flexible
what is low density poly ethene used for ?
bags
bottles
how is high density poly ethene made ?
at lower temperature and a lower pressure
give properties of high density poly ethene ?
rigid
when is high density poly ethene used ?
water tanks
drain pipes
give properties of metals ?
malleable
good conductors of heat and electricity
ductile
shiny
stiff
sonorous
what is copper used for and why ?
electrical wires - conducts electricity well, and is ductile
what is an alloy ?
mixtures of 2 or more metals or a mixture of a metal and a non - metal
why are alloys better than pure metals ?
man pure metals are too soft for uses
why are pure metals soft ?
their layers of atoms slide easily past each other
why are alloys harder than pure metals ?
they are made from atoms of different elements which have different sized atoms so the layers are distorted so it is more difficult for atoms to slide past each other
give properties of iron ?
soft
easily shaped
bendy
what is iron used to make ?
alloys called steels
how are steels formed ?
by adding small amounts of carbon to the iron
what are the properties of low carbon steel ?
easily shaped
what is low carbon steel used to make ?
car bodies
what are the properties of high carbon steel ?
strong
inflexible
brittle
what is high carbon steel used to make ?
blades
bridges
what are the properties of stainless steel ?
corrosion resistant
hard
what is stainless steel used for ?
cutlery
containers for corrosive substances
what is bronze an alloy of ?
copper and tin
what are the properties of bronze ?
hard
what is bronze used for ?
statues
decorative objects
medals
what is brass an alloy of ?
copper and zinc
give properties of brass ?
gold like appearance
malleable
what is brass used for ?
door fittings
water taps
why are gold alloys used ?
gold is too soft
what are gold alloys used for ?
jewelry
what makes gold alloys ?
zinc
copper
silver
what are the benefits of a gold alloy ?
cheaper
what is the amount of gold in an item described in ?
carats
what is pure gold described as ?
24 carat
what is aluminium used for ?
aircraft manufacture
why can’t pure aluminium be used ?
it is too soft
so it is alloyed with other metals to make it stronger
what is corrosion ?
when a metal is gradually destroyed by reacting with substances in the environment
give an example of corrosion ?
iron rusting
what needs to be present for corrosion ?
oxygen
water
what is rust also known as ?
hydrated iron oxide
what is the word equation for iron rusting ?
iron + oxygen + water - hydrated iron oxide
where does corrosion happen in a material ?
at its surface
why does corrosion happen at the surface of a material ?
it is exposed to air there
why will iron that wasn’t initially at the surface eventually corrode away ?
the iron initially at the surface will crumble and flake off to leave more iron available to rust
why aren’t objects made from aluminium completely destroyed by corrosion ?
the aluminium oxide that forms when aluminium corrodes doesn’t flake away so a protective layer is formed preventing any further corrosion happening
explain a rust experiment which shows oxygen and water is required for rust to form ?
- put an iron nail in a boiling tube with just water - it won’t rust
- put an iron in a boiling tube with just air - it won’t rust
- put an iron nail in a boiling tube with air and water it wil rust
why will the mass of a rusty nail increase as it rusts ?
iron atoms in the nail will have bonded to oxygen and water molecules resulting in a compound which is heavier than just iron
why is preventing corrosion important ?
- structures could become damaged and dangerous to use, e.g bridges
what are the 2 ways to prevent corrosion ?
creating a barrier
sacrificial method
how can creating a barrier prevent corrosion ?
- it keeps out water and oxygen
give an example of how barriers are created to prevent corrosion in small objects ?
paint
coating with plastic
explain how barriers are created to prevent corrosion using electroplanting ?
it uses electrolysis to reduce metal ions onto an iron electrode
give an example of when oil/greasing is used to prevent corrosion ?
bike chains
what is the sacrificial method to prevent corrosion ?
placing a more reactive metal with the metal you want to protect because water and oxygen will then react with that metal instead of the less reactive metal
give an example of when creating a metal and using the sacrificial method is used to prevent corrosion ?
an iron object can be galvanished by spraying with zinc which is protective and more reactive than iron
how are natural resources formed ?
without human input
what do natural resources include ?
anything that comes from
earth
sea
air
what are natural resources used for ?
providing energy for things
building materials
food
give an example of how a natural resource is used ?
wind generates electricity by wind turbines
what does agriculture provide ?
conditions where natural resources can be enhanced
what are renewable resources ?
materials which can be re-formed at a similar rate or faster than we use them
give an example of a renewable resource ?
timber
what is a non - renewable resource ?
materials which cannot be formed quickly enough to be considered replaceble
give examples of finite resources ?
fossil fuels
nuclear fuels
minerals and metals found in ores
what is sustainable development ?
an approach to development that takes account of the needs of present society while not damaging the lives of future generations
why is using finite resources unsustainable ?
lots of energy is used
lots of waste is produced
give a way of reducing the use of finite resources ?
using them less
recycling - uses less energy
reusing objects
give examples of new, more sustainable methods to extract copper from its ores ?
bioleaching
phytomining
what is bioleaching ?
using bacteria which convert copper compounds into the ore into soluble copper compounds - separating copper from the ore in the process
describe bioleaching
- leachate (solution produced) contains copper ions which can be extracted by electrolysis or displacement reactions
why is scrap iron used to displace copper from solutions ?
cheap
reduces scrap going to landfill
what is phytomining ?
growing plants in soil which has copper
how does phytomining work ?
plants cannot use or get rid of copper so it gradually builds up in the leaves
plants are harvested dried and burned in a furnace
the ash contains copper compounds and can be displaced using electrolysis or more reactive metals
what are the advantages or phytomining and bioleaching ?
- requires less energy
- low grade ores do not need to be mined in the same ways as high mined ores which protects habitats
- earth does not need to be dug up
what are the disadvantages of bioleaching and phytominig ?
slow
what are the advantages of recycling ?
- it uses waste materials to make new products
- uses little energy
- saves money
- conserves finite resources
- cuts down rubbish sent to landfill
what does resusing mean ?
using a product more than once for the same or different purpose
how are metals recycled ?
melted down
casted into the shape of the new product
how is glass separated during recycling ?
by colour
chemical composition
how is glass recycled ?
crushed down
melted to be reshaped before being recycled
what are life cycle assessments ?
things that asses the environmental impact of the entire lifetime of a product
what are the stages of a lifetime of a product ?
- getting the raw materials
- manufacturing and packaging
- using the product
- product disposal
what needs to be considered during each stage of the lifetime of a product ?
how many other resources are used
energy needed
pollution produced
waster formed = how waste is disposed
what can extraction of a raw material do ?
damage environment
pollution
what can transportation of raw materials lead to ?
greenhouse gases from combustion of fossil fuels
what can manufacturing products cause ?
uses lots of energy
pollution
waste products from reactions used to make compounds
what is considered by life cycle assessments ?
how long a product is used for
why can products which needs more energy to produce but have a long life be better ?
it may mean less waste and raw materials
why can product disposal be harmful ?
- energy used when transporting to landfill
- waste takes up space
- may pollute land/water
- non -biodegradable products take a long time to degrade
what is incineration ?
when waste is burnt at high temperatures
what are the benefits of incineration ?
it cuts down waste going to landfill and can be used to generate electricity
what is the issue with incineration ?
causes air pollution
what are life cycle assessments used for ?
evaluating different products and allowing decisions to be made about which products has the least environmental impact
what are the problems with life cycle assessments ?
- effects of some pollutants is hard to give a numerical value
- they can be biased as it uses an objective method
- selective LCAs only show some of the impacts of a product on the environment which can be biased as they can be written to support the claims of a company
give an example of a life cycle assessment used -
plastic vs paper bags
what do life cycle assessments of paper vs plastic bags show ?
even though plastic bags aren’t biodegradable they take less energy and have a longer lifespan than paper bags so are less harmful
what is potable water ?
water that has been treated or is naturally safe for humans to drink
what is pure water ?
H20 molecules ONLY
what things need to be in potable water to make it drinkable ?
- levels of dissolved salts aren’t to high
- pH between 6.5 and 8.5
- there aren’t dangerous bacteria or microbes swimming around in it
what does how potable water is produced depend on ?
- climate
- landscape
- cost
what is fresh water ?
water that doesn’t have much dissolved in it
give an example of fresh water ?
rain water
name 2 ways rain water can be collected
as surface water
as ground water
in the UK what type of water is the majority of water we drink ?
fresh water
what does the source of fresh water chosen depend on ?
location
in warm areas where does most of the domestic water supply come from and why ?
ground water as surface water dries up from the heat
why does fresh water need to be treated before we can drink it ?
so it is safe
how is water treated ?
filtration
sterilisation
what is filtration in water ?
a wire mesh screens filters out large things then gravel and sand beds filter out any solid bits
why is water sterilised ?
water is sterilized to kill any harmful bacteria or microbes
how is water sterilised ?
by bubbling chlorine gad through it
using ozone or ultraviolet light
why do some dry countries have to use sea water ?
there isn’t enough surface or ground water
how must sea water be treated to produce potable water ?
desalination
how can desalination be done ?
distillation
process that use membranes, e.g reverse osmosis
what happens to sea water during reverse osmosis ?
salty water is passed through a membrane that only allows water molecules to pass through
Ions and larger molecules are trapped from the membrane and separated by the water
what are the disadvantages of distillation and reverse osmosis ?
expensive
uses lots of energy
how is seawater checked before it is considered safe to drink ?
if it has high levels of salts it needs to be distilled
how do you test water before distilling it ?
- check the pH using a pH metre - if it is too high or low you need to neutralise it
- test for presence of sodium chloride
how can you change the pH level to neutralise the water ?
with a titration then test with a pH metre to see if it is neutral
how do you test for sodium ions ?
flame test - if sodium ions are present sample will turn yellow
how do you test for chloride ions ?
add dilute nitric acid to silver nitrate solution to water, if chloride is present a white precipitate will form
how do you distill water ?
pour salty water into distillation apparatus
heat flask from below
water will boil and form steam leaving any dissolved salts in the flask
steam will condense back to liquid water and can be collected
repeat test for sodium chloride and pH to check water is safe
consolidate the steps for how to test and distil water
1 - test pH
2 - test for sodium ions
3- test for chloride ions
4 - distill water
5- retest water for pH and sodium chloride to check it is safe to drink
in the home what do we use water for ?
baths
toilet
washing up
what happens when we flush water from our homes ?
it goes into the sewers and towards sewage treatment plants
why does sewage from domestic or agricultural sources need to be treated ?
to remove organic matter or harmful microbes before it can be put back into fresh water sources
what are the issues with using unclean water ?
it can pollute lakes
cause health risks
what can industrial waste contain ?
organic matter
harmful chemicals
what are the stages of waste treatment ?
screening
sedimentation
aerobic digestion
anaerboic digestion
what is screening ?
sewage is screened - large bits of material is removed
what is sedimentation ?
screened waste is put in settlement tank and heavier suspended solids sink to the bottom producing sludge while the less dense effluent floats to the top
what is aerobic digestion ?
air is pumped through the water to encourage aerobic bacteria to break down any organic matter - including microbes
what is anaerobic digestion ?
sludge from the bottom of the tank is removed and put into large tanks
sludge gets broken down - anaerobic digestion is breaking down the organic matter in sludge
what does sludge release during anaerobic digestion ?
methane gas
what is methane gas used for ?
energy
what is digested waste used for ?
fertilisers
how is waste water with toxic substances cleaned ?
they add chemicals
UV radiation
Membranes
are added to the other steps
what is the advantage of sewage treatment ?
uses less energy
when can retrieving potable water via sewage treatment be beneficial ?
in areas where there is not much fresh water
what happens in the haber process ?
nitrogen and hydrogen gas are used to make ammonia
where is nitrogen found ?
in the air
where is hydrogen found ?
reacting methane with steam
crude oil
what is the reversible reaction to form ammonia in the Haber process ?
nitrogen + hydrogen = ammonia
N2 + 3H2 = 2NH3
how is forming ammonia a reversible reaction ?
ammonia is formed then breaks down into nitrogen and hydrogen again
describe what happens in the reaction vessel during the Haber process ?
- gas is cooled in a condenser and liquifies
- liquid ammonia is removed
- unused nitrogen and hydrogen are recycled
how is nitrogen and hydrogen being recycled beneficial in the Haber process ?
it reduces waste
saves resources
reduces cost
what conditions are being formed in the haber process ?
temperature at 450 C
Pressure - 200 atmospheres
catalyst - iron
what is the forward reaction of the Haber process - exothermic or endothermic ?
exothermic
why is it bad that the forward reaction of the Haber process is exothermic ?
it moves the equilibrium the wrong way - away from ammonia towards nitrogen and hydrogen
at what temperature is the yield of ammonia best ?
lower temperatures
why is it difficult that to get a better yield of ammonia a lower temperature is used ?
lower rate of reaction - so temperature is increased anyway
why is higher pressure good for the Haber process in making ammonia ?
it moves the equilibrium towards ammonia so it increases the yield and rate of reaction
why can’t the pressure be put too high during the Haber process ?
it is too expensive
what is the advantage of having an iron catalyst during the Haber process ?
it makes the reaction go faster so reaches equilibrium faster
why is a catalyst important during the Haber process ?
without it the temperature would be raised even more so the percentage yield would decrease even more
leading to
it being more costly
higher energy usage
how does presenting experiments in different conditions through graphs help scientists ?
they can find the best conditions for a reaction to take place
what are the 3 main element needed for growth ?
nitrogen
phosphorous
potassium
why may nitrogen potassium and phosphorous be missing from the soil ?
if they have been used up by the previous crop
what will happen if plants don’t get enough nitrogen phosphorous and potassium ?
stunted growth
life prcesses affected
what do fertilisers do ?
replace the missing elements or provide more of them which helps to increase crop yield
what are NPK fertilisers ?
formulations containing salts of nitrogen, phosphorous and potassium in the right percentage of the elements
what can ammonia react with to help produce fertilisers ?
- oxygen and water to form nitric acid
- nitric acid - to form ammonium nitrate
why is ammonium nitrate good for a fertiliser ?
it has a high proportion of nitrogen
what is the equation wen reacting ammonia and nitric acidn?
NH3 + HNO3 - NH4NO3
why are the processes of producing fertilisers different in the laboratory or in industry ?
scale and speed of the operation determines the methods used in the process -
industry - lots needs to be made quickly to keep up with demand
lab - smaller amounts in batches
how is ammonium nitrate formed in industry ?
- ammonia gas is added directly to giant vats containing highly concentrated nitric acid
- this give an exothermic reaction
heat released evaporates water making a very concentrated ammonium nitrate product
how is ammonium nitrate formed in labs ?
- carried out on a smaller scale by titration and crystallization
- ammonia solution is used and the reactants are at a lower concentration than in industry so les heat is produced and it is safer
- after the titration the mixture needs to be crystallised to give pure ammonium nitrate crystals
why isn’t crystallization happening in industry to form ammonium nitrate ?
slow
what can phosphate rock be reacted with to form fertilisers ?
- nitric acid = phosphoric acid and calcium nitrate
- sulfuric acid = calcium sulfate and calcium phosphate
- phosphoric acid - calcium phosphate
what can be mined as a source of potassium ?
potassium chloride
potassium sulfate
can phosphate rock be a fertiliser on its own ?
no
