USING RESOURCES Flashcards
what are ceramics
ceramics are non metal solids with high melting points that aren’t made from carbon based compounds
what can ceramics be made out of
clay
examples of ceramics
clay and glass
clay
can be moulded into different shapes as it is soft when its dug up from the ground
when its fired at high temperatures it hardens to form a clay ceramic
glass
is transparent
can be moulded when hot and can be brittle when thin
what is most glass
soda lime glass
how is soda lime glass made
it is made by heating a mixture of limestone, sand and sodium carbonate until it melts
when the mixture cools it comes out as glass
what is borosilicate glass
it has a higher melting point than soda lime glass and it is made in the same way as soda lime glass
it is made using a mixture of sand and boron trioxide
what are composites
are made of one material embedded in another. fibres or fragments of a material are surrounded by a matrix acting as a binder
what do the properties of composite’s depend on
depends on the matrix/binder and the reinforcement used to make them
examples of composites
fibreglass
carbon fibre
concrete
wood
what does fibre glass consist of and what are its properties and what is it used for
glass embedded in a matrix made of polymer. it has a low density but is very strong
it is used for things like skis boats and surfboards
what does carbon fibre consist of and what are its properties and what is it used for
they have a polymer matrix and the reinforcement is made from long chains of carbon atoms bonded together
they are very strong and light
they are used in aerospace and sports manufacturing
what does concrete consist of and what are its properties and what is it used for
is made from aggregate embedded in cement
its very strong
this makes it ideal for use as a building material eg in skate parks
what does wood consist of and what are its properties and what is it used for
natural composite of cellulose fibres held together by an organic polymer matrix
what two things influence the properties of a polymer
the catalyst that was used and the reaction conditions (the temperature and pressure) that it was made under
example of the two things that affect a polymer
eg low density polyethene- is made from ethene at a moderate temperature under a high pressure and with a catalyst === its flexible and is used for bags and bottles
high density polyethene is also made from ethene but at a lower temp and pressure with a different catalyst
its more rigid and is used for water tanks and drainpipes
what are thermosoftening polymers
they contain individual polymer chains entwined together with weak forces between the chain.
you can melt these plastics and remould them
what are thermosetting polymers
contain monomers that can form cross limks between the polymer chains, holding the chain together in a solid structure.
these polymers don’t soften when theyre heated
theyre strong hard and rigid
examples of clay ceramics
porcelain and brick
what are polymers
insulators of heat and electricity, they can be flexible and easily moulded
they have many applications including in clothing and insulators in electrical items
metals
are malleable, good conductors of heat and electricity, ductile, shiny and stiff
what the problem with pure metals
theyre too soft
why are alloys better than pure metals
alloys are much harder than pure metals as they are a mixture between two or more metals or a metal and another element pure metals are too soft
why are alloys harder than pure metals
when another metal is mixed with a pure metal to make an alloy the new metal atoms will distort the layers of metal atoms making it more difficult for them to slide over each other. This makes alloys harder than pure metals.
what are allos of iron called
steel
how are steels made
by adding small amounts of carbon and sometimes other metals to iron
how is bronze, brass, made
bronze- copper + tin
brass- copper + zinc
why are gold alloys used to make jewellery q
pure gold is too soft
metals such as zinc, copper, and silver are used to harden gold
how many carats is pure gold
24
what does 18 carat mean
this means that 18 out of the 24 parts of the alloy are pure gold so 18/25= 75%
18 carat gold is 75% gold
what is corrosion
is when metals react with substances in their environment and are gradually destroyed
rust
rust is only used to describe the corrosion of iron
what corrodes easily
iron
what needs to happen in order for iron to rust
it needs to be in contact with both oxygen and water which are present In the air
what is actually rust
compound hydrated iron(iii) oxide
equation for rust
iron + oxygen + water——-= hydrated iron oxide
when only can corrosion happen
only happens on the surface of a material where its exposed to the air
what other than iron corrodes when it comes in contact with air
aluminium also corrodes when exposed to the air however it is not completely destroyed by corrosion
what happens in the corrosion of aluminium
when aluminium oxide corrodes the aluminium oxide that forms doesn’t flake away it forms a protective layer that sticks firmly to the aluminium below and stops any further reaction taking place
what happens when iron rusts
iron oxide flakes form on the surface of the iron, as its soft and crumbly it flakes off to leave more iron available to rust again eventually all the iron corrodes away
experiments that show that both oxygen and water are needed for iron to rust
if you put an iron nail in a boiling tube with just water it wont rust, (the water is boiled to remove oxygen and oil is used to stop air getting in
if you put an iron nail in a boiling tube with just air, it wont rust (calcium chloride can be used to absorb any water from the air)
how do make iron rust in a boiling tube
put an iron nail in the boiling tube with air and water it will rust.
ways to prevent rusting
to coat the iron with a barrier to keep out the water and oxygen- can be done by painting/coating in plastic ,, electroplating ,, oiling/greasing
the sacrificial method this involves placing a more reactive metal such as zinc or magnesium with the iron , water and iron the react with the sacrificial metal instead of with the metal
what is a galvanised nail and what happens
a galvinised nail is a nail that is sprayed with a coating of zinc. the zinc layer is a protective layer and prevents the nail from rusting.
what happens if a galvanised nail is scratched
the zinc around the site of scratch work as a sacrificial metal
where do natural resources come from
the earth, sea and air
what is a renewable resource and an example
they reform at a similar rate to or faster than we use them
eg timber, is a renewable resource as trees can be planted following a harvest and only take a few years to regrow, other examples include fresh water and food
what are finite resoureces
they aren’t formed quickly enough to be considered replaceable
they include fossil fuels and nuclear fuels such as uranium and plutonium. minerals and metals found in ores in the earth are also non renewable materials
why does extracting finite resources have risks
eg mining metal ores is good because useful products can be made it also provides people with jobs and brings money into the area, however mining ores is bad for the environment as it uses loads of energy scars the landscape and produces lots of waste and destroys habitats
using examples state the difference between a finite and renewable source
a finite resource such as crude oil, will take a long time to replenish, on the other hand renewable resources such as timber can be replaced within a relatively short time scale.
what is sustainable environment
is an approach to development that takes account of the needs of present society while not damaging the lives of future generations
what can be unsustainable
using unrenewable resources
extracting resources due to the amount of energy used and waste produced
processing resources into useful materials such as glass or bricks
how can we lower the amounts of use of finite resources
chemists can develop and adapt processes that use lower amounts of finite resources and reduce damage to the environment
eg chemists have developed catalysts that reduce the amount of energy required for certain industrial processes
how to improve the sustainability of copper
extracting it from low grade ores by
biobleaching- bacteria are used to convert copper compounds in the ore into soluble copper compounds, separating out the copper from the ore in the process, the leachate( the solution produced by the process of biobleaching) contains copper ions which can be extracted by electrolysis
Phytomining- this involves growing plants in soil that contains copper. copper builds up in the leaves, the plants can be harvested dried and burned in a furnace. the ash contains soluble copper compounds from which copper can be extracted by electrolysis
why cant you use traditional methods to extract copper
they can damage the environment
what are the adv and dis of the new methods of extraction
they have a much smaller impact on the environment but they are slow
three positive effects of recycling metals
saves energy needed to extract metals from the earth
conserves limited supplies of metals from the earth
cuts down on the amount of waste going to landfill
what has to happen if a company wants to manufacture a new product
they carry out a life cycle assessment
what does an LCA show
it looks at every stage of a products life to assess the impact it would have on the environment
LCA detailed
getting the raw materials- extracting raw materials needed for a product can damage the local environment eg mining metals
raw materials often need to be processed to extract the desired materials and this often needs large amounts of energy
manufacturing and packaging- manufacturing products and their packaging can use a lot of energy resources and can cause a lot of pollution eg harmful fumes such as carbon monoxide or hydrogen chloride
also think about need to think about any waste products and how to dispose of them. The chemical reactions used to make compounds from their raw materials can produce waste products
using the product- the use of a product can damage the environment for example burning fuels releases greenhouse gases and other harmful substances , fertilisers can leach into streams and rivers causing damage to ecosystems,, how long a product is used for or how many uses it gets before it gets
product disposal- products are often disposed of in landfill sites. this takes up space and pollutes land and water
energy is used to transport waste to landfill, which causes pollutants to be released into the atmosphere
products might be incinerated which causes air pollution
problems with the lca model
the use of energy, some natural resources and the amount of certain types of waste produced by a product over its lifetime can be easily quantified
so producing an lca is not an objective method as it takes into account the values of the person carrying out the assessment, this means the lca can be biased
selective LCAs which only show some of the impacts of a product on the environment can also be biased as they can be written to deliberately support the claims of a company
