c13 and c14

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what is one theory about the earths early atmosphere - volcanoes
that volcanoes released CO2, water vapour and nitrogen, and formed the early atmosphere. water vapour coolec and fell as rain, collected in hollows in the crust as rocks solidified, and first oceans were formed.
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what is another theory about the earths early atmosphere - comets
comets brought water to the earth, as icy comets rained down on the earths surface, they melted adding to its water supplies
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what happens when the earth's atmosphere stabalises
mainly CO2, maybe some nitrogen and traces of methane, but little or no O2, like mars and venus
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what were the first organisms on earth
baceria and simple organisms like algae which evolved
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how did algae evolve
algae could use the nergy from the sun to make their own food by photosynthesis, producing oxygen gas as a waste product, levels of O2 steadily increased as the bacteria and algae thrived in the seas. they removed co2 and added o2
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how did oxygen become part of the earths atmosphere
made from the first simple organisms that could carry photosynthesis and then evolving
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what happens when the plants evolved
they successfully colinised most of the earths surfaces. so the atmosphere was richer in o2, making it possible for animals forms to evolve
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what did the first forms of animals rely on
the algae and plants for their food and oxygen to respire
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why did some of the first living microorganisms die
they could not tolerate the high levels of oxygen, as they evolved without it, didn't need it
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what is the equation of photosynthesis
carbon dioxide + water > glucose + oxygen
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what is coal classed as
a sedimentary rock, formed from thick deposits of plant material, like ancient trees and ferns, when these died in the swamps, they were burried, in absence of oxygen and compressed for over a million years
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how was crude oil and natural gases formed
remians of plankton deposited in muds on the sea bed. these remains were covered by sediments that become layers of rock when compressed for ages. it is formed and found trapped beneath the layers of rock
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what does photosynthesis do
removed co2, decrease the levels
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what do fossil fuels and formation of sedimentary rocks do
remvoed co2 from atmosphere
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what did methane and ammonia react with in the early atmosphere
oxygen formed by evolving plants and algae
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what happens when methane and ammonia react with oxygen
they both produce water and remove ammonia and methane
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waht are the equation for methane and ammonia reacting with oxygen
methane - CH4 + 2o2 > CO2 + 2H20 and ammonia - 4NH3 + 3o2 > 6H2O
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what could happen to the levels of nitrogen
build up, as it is very unreactive
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how was the old carbon dioxide rich atmosphere removed
it became locked up in the earths crust in rocks and fossil fuels, dissolving in water in the oceans, reacted with metal oxides which made insoluable carbonate compounds, fell to the seabed as sediments to form more carbonate rocks
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what is the natural cycle of carbon
carbon moves between oceans, rocks and the atmosphere
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how were sedimentary carbonate rocks formed
skeletons/shells built up at bottom of oceans, covered by layers of fine sediment, pressure caused burrying under the layers of sediment. eventually, the deposits formed these rocks such as limestone (mainly calcium carbonate)
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what are the percentages of gases in todays atmosphere
78% nitrogen, 21% oxygen, 0.9% argon, 0.04% carbon dioxide, and traces of other gases
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what are the main greenhouse gases
methane, carbon dioxide, and water vapour
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what are greenhouse gases
the gases that absorb energy radiated from its surface, they warm the earth
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waht happens when the earth is heated by the sun
som eis reflected back into space, the greenhouse gases let uv light pass, and they absorb infared radiation,
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what type of wavelength does greenhouse gases let pass through
short wavelength electromagnetic radiation - UV light, can pass
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how does the earths surface cool down
by emitting longer wavelength infrared (thermal) radiation. this stimulated the bonds in these molecules to vibrate, bend and stretch more vigorously, raising their temp
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what does infrared radiation do to the atmosphere and tempurature
this stimulated the bonds in infrared radiation stimulates molecules to vibrate, bend and stretch more vigorously, raising their temp so some of the energy radiated from the surface gets trapped in the atmosphere and temp rises
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if there are more greenhouse gases, how does this affect the energy
more energy is absorbed
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how does methane get into the atmosphere
from swamps and rice fields, emissons from the number of cattle grazing and their decomposing waste, increasing human population, more waste of landfill sites
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how does human activity affect the levels/ balanced co2
balance between produced and absorbed by carbon sinks (tropical rainforests/oceans) humans cause deforestation, photosynthesis reduced means less is removed by plants. as temp rises, co2 gets less soluble in water,oceans ineffective as carbon sinks
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what are scientists investigating about climate change and co2 levels
getting evidence, a link between them. one source is the ice cores drilled from greenlands ice sheet which have gases trapped inside, they can analyse these, to see the change in composition overtime, but cant predict the effects with certainty
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what are the consequences of rising levels of greenhouse gases
rising sea levels , melting ice caps and flooding, increased coastal erosion, increasing common extreme weathers, changes in temp and distribution between rainful. impact food production, changes in the distribution of wildlife, extinction
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what is the carbon footprint
the carbon footprint of a product, service, or event is the total amount of carbon dioxide and other greenhouse gases emitted over its full life cycle
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what is the carbon capture and storage technique involve
pump carbon dioxide produced in fossil fuel power stations deep underground to be absorbed into porous rocks, this could be done in old, oil fields, increases the cost of produced electricity
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how could methane decrease
if the number of cattle grazing decreased, so a decreased demand for beef. plant based diets offer more efficient use of land to grow crops than feed animals
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how are the governments helping to reduce co2 levels
spending money to research alternative forms of energy, taxing fossil fuels + cars that burn lots of fuels. support use of biofuels. incentives given to improve home insulation - conserve energy, policies to control planting/destruction of trees
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what are the problems of reducing the carbon footprint
incomplete international co-operation on setting targets due to scientific diagreements, no real evidence. reduction will have cost implications, poorer countries cant afford it, hinder developing industries.
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how can co2 levels be decreased easily
walk/ cycle more/ public transport, sharing lifts, recycle waste, less electricity used at home means less fossil fuels used
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whhat do fossil fuels contain
impurities - sulfer
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what does sulfur react with when a fossil is burnt
sulfer reacts with oxygen to make sulfer dioxide, acidic and toxic, bad for environment as it causes acid rain
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what does sulfur dioside cause
acid rain, damging trees, killing animal/plant life, attacks builiding(especially limestone buildings/metal like structures)
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when can sulfur dioxide be removed
before fossil fuel is burnt, happens in petrol and diesel for cars and gas-fired power stations.
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what is incomplete combustion
when not enough oxygen is present
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what happens if there is not enough oxygen in an engine
incomplete combustion, carbon monixide is produced (gas) colourless, odorless so cannot tell if you are breathing it in. red blood cells carry this instead of o2 sometimes
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what happens if carbon monoxide is carried in the blood instead of oxygen
takes up sites of haemoglobin in red blood cells that usually bond to oxygen, it will be poisoning and starved of oxygen, drowsy, loose consciousness and death
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what can high temps in an engine cause
the normally unreactive nitrogen gas could react with oxygen to make nitrogen oxides
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what effects can nitrogen oxides have
toxic, can trigger asthma and acid rain
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what do diesel engines burn
hydrocarbons with bigger molecules than petrol engines
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what happens when these large molecules react with oxygen in the engine
they might not burn completely, tiny solid particles (containing carbon) and unburnt hydrocarbons are produced called particulates are carried in the air.
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what do particulates cause
travel into upper atmosphere, reflecting sunlight back to space, causing global dimming, may damage lung cells and even cause cancer
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what is sulfure dioxide
oxidation of sulfur impurities in fossil fuels
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what are finite resources
used up at a faster rate than they can be replaced, if they are constantly used at this rate they will eventually run out.
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what are some examples of finite resources
coal, crude oil, natural gas
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what are renewable resources
those that can be replaced at the same rate they are used up.
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what is an example of renewable resource
the crops used to make biofuels
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what does the chemistry industry use to make new materials
natural resources as the raw materials to make the new products
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how are metals extracted
metal ores are used
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how are polymers and petrochemicals made
crude oil
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how are concrete/cement made
limestone
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what does crude oil make
petrol, diesel, kersene
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what still dont we know about finite resources and there involvement in the future
what will the future rate be, how long will it last, how accurtely do we know the amounts of finite resources, will new resources be discovered
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how are we trying to avoid using finite resources
using renewable resources to conserve it and improve sustainability
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how can plastic be produced more effectively
many of the polymers use ethene from crude oil, but ethene can also be made from ethanol, which can be made from fermenting glucose from sugar cane/sugar beet. so using a renewable crop as the raw material for ethene makes plastics > poly(ethene)
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how can power stations be improved
isntead of using fossil fuels, wood chips could be used to fuel power stations
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what happens when rainwater comes into contact with the surface
it will dissolve soluble substances as it passes over them, so water from natural sources will contain dissolved minerals(salts) as well as microorganisms from soil and decaying matter, collects in rives/lakes
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what do the best sources of fresh water contain
low levels of minerals and microbes to start with, less time to remove as there is less of it
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what is potable water
water containing low levels of bacteria and dissolved minerals
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what is pure water
water containing no dissolved minerals/bacteria/or any other substances
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what are the steps when purifying water
filteration (coarse screen) removes large objects the sedimentation - soil and sand settle to the bottom of a tank and are removed then filteration to remove fine particles, the chlorination/uv light to sterilize/kill bacteria and ph check
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what is desalination
removal of dissolved salt from sea water
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how can desalination be done
by distillation however this requires energy or can be done by reverse osmosis
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what is reverse osmosis
water passed through thin membranes to remove dissolved salts
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analysis and purification of water samples before and after, residue/distilate - REQUIRED PRACTICAL
before distillation - water is colourless after distillation, collected water (distilate) ph7 and no salts, residue water is resting in flask with dissolved salts
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what are the steps of this REQUIRED PRACTICAL
sample of salty water to test ph and another to desalinate by distillation, put salt solution in a conical flask with a bung above a bunsen burner, distillate collected in the test tube (pure water) and use universal indicator
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what is flash distillation
as not all countries have sufficient amounts of rain or natural sources of fresh water and the economic development, under reduced pressure water can boil below 100, saving energy costs
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what needs to be removed from sewage/agriculture water waste
removal of organic matter/harmful microbes
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what might be removed from industrial waste water
harmful chemicals or removal organic matter
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what are some methods of sweage treatment
screening and grit removal, sedimentation to produce sewage slude and effluent (liquid waste/sewage discharged into sea/river) or anaerobic digestion of sewage sludge and aerobic biological treatment of effluent
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what is anaerobic digestion
sewage sludge mixed with bacteria to produce methane which is used as a fuel
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what are the steps invovled with sewage treatment
material passes through a grid, removes solid material that get flushed down toilet, sewage goes into a grit tank, pieces of grit sink to bottom, then into sedimentation tank, human waste sinks to bottom forms a sludge leaving liquid(effluent)
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what happens in sewage treatment after effluent is made from human waste in the sedimentation tank
biological treatment - anaerobic digestion, useful baccteria feed on any remain organic matter/harmful microorganisms, breaking them down anaerobically. tank is aerated by bubbling air through the water waste
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what affects the time it takes to bubblr air through water waste
quality of the water waste, size of tank, rate of aeration, temp
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what is the final treatment in the sewage treatment
in the last tank, useful bacteria are allowed to settle out to bottom of tank as a sediment, which is recycles back to second treatment or into sludge treatment, this waste wter is safe to discharge into rivers
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what happens if the ecosystem is sensitive
water can be filtered again through a bed of sand and maybe streilised by uv light/chlorine, but chlorine can cause concern
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what is the treatments of sewage treatment
screening, solid sediments settle and effluent forms, aerobic digestion removed remaining harmful microorganisms/orgnaic matter, tank aerated, useful bacteria settle to bottom as a sediment which is recycled
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how can the sludge be used
dried and used as a fertiliser on farmland to improve soil or a source of renewable energy.
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what does sludge contain
organic matter, human waste, suspended solids, dissolved compounds. digested anaerobically by microorganisms beneath surface in treament tank
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how can the biological treatment be carried out
relatively high temps 55/35, the higher the temp the quicker it is to breakdown the organic matter
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what is biogas
methane co2 and some hydrogen sulfide - mix can be burned to power sewage treatment or electricity for surrounding area. further cleaned to make methane maybe.
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what can the sludge turn into
dried, form a crusty solid, to be burnt to generate electricity
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where is most copper extracted from
copper-rich ores
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how can copper be extracted
sulfuric acid is used to produce copper sulfate solution before extracting the copper metal, or smelting. the copper ore is heated to a high temp in a furnace with air to produce impure copper
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what happens in smelting
copper ore is heated at high temp, furnace + air, impure copper is produced and then used at the anode, makes pure copper.
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disadvantages of smelting
huge amounts of energy and electricity required, lots of money needed
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what charge do metal ions have and where are they attracted to
positively charged, attracted to and deposited at cathode
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when copper is purified by electrolysis, what happens at the cathode
reduction, cu2+2e->cu
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when copper is purified by electrolysis, what happens at the anode
oxidation, cu>cu2+ + 2e-
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where else can copper be extracted from
from copper sulfate in industry by adding scrap iron. iron can displace copper from its solutions
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what is the displacement reaction between copper sulfate and iron
iron + copper sulfate > iron sulfate + copper
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how are we trying to avoid using the limited copper rich ores
trying to extract copper from low grade ones instead, uneconomical using traditional methods but new methods including bacteria (bioleaching) or plants (phytomining) to help extract copper
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what happens in phytomining
plants that absorb copper iosn, they are grown on soil containing low grade copper ore. plants are harvested+burnt and copper is extracted from copper compounds in the ash. the ions can be leached (dissolved) from ash by adding sulfuric acid
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what happens in bioleaching
bacteria feeds on low grade metal ores, and a combination of biological and chemical processes, a solution of copper ions can be obtained from waste copper ore. scrap iron and electrolysis is used to extract copper from the leachate
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advantages and disadvantages of phytomining
extracts copper from low grade ores, conserves copper rich ores, doesn't detroy landscape/habitats, less visual pollutiuon. produces smaller amounts of copper, alot of space, long time growing plants, co2 produced when plants are burnt
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advantages and disadvantages of smelting
quicker, extracts more copper, more economically viable, copper rich ores are limited, mining causes dust/noise pollution, destructuion of habitat, nonrenewable fuel used, more use of energy/electricity, acid rain(rleased sulfur dioxide)
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what is the life cycle assessment
a technique used by government agencies, businesses and industry used to assess the impact on the environemtn caused by getting/processing raw materials, making produc(packaging),using, reusing and maintaining product, disposal of product
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how is the life cycle assessment carried out
listing all energy/material inputs and the outputs into environment, evaluating the potential environmental impacts from inputs/outputs, interpreting results to help make decisions about it again
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what does the life cycle assessment provide
an estimate of the total environmental impacts throughout all the stages of the products life
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how is the life cycle assessment summarised in stages
raw material extraction > manufacture > use/reuse/maintainance > recycle?waste management
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why might some parts of the life cycle assessment is not objective
subjective judgements, assumptions due to lack of data
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what do we aim to reduce
the use of limited resources, our use of energy, the waste we produce
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what benefits are there of recycling
saves energy, saves money, helps the environment as less pollutiuon from mining
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what does recycling aluminium involve
melting the scrap metal uses less energy than extracting it from its ore (bauxite)
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what is another theory about the earths early atmosphere - comets

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comets brought water to the earth, as icy comets rained down on the earths surface, they melted adding to its water supplies

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what happens when the earth's atmosphere stabalises

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Card 4

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what were the first organisms on earth

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Card 5

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how did algae evolve

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