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The chemical equation for a reaction of sodium is shown below
2Na + Cl2 ==> 2NaCl
desrcibe this reaction in terms of the names of the substances and the atoms involved
(3)
- 2 sodium atoms react
- with 2 chlorine atoms
- 2 sodium ions and 2 chlroine ions are produced
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poly(ethene) molecules are made from ethene molecules by a polymerisation reaction
describe what happens in a polymerisation reaction
(2)
- many monomers/ethenes
- join/bond togther
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what are the positive environmental effects of reusing plastic bags
- • used to make new plastic bags / objects
- • saves raw materials / crude oil
- • saves energy compared to producing plastic bags from crude oil
- • cuts down on CO2 emissions
- • less global warming
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what are the negative environmental impacts of reusing plastic bags
- • collection point sites cause an eyesore / litter problem
- • transportation to recycling plant releases carbon dioxide / causes global warming
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what are the positive enviornmental impacts of burning plastic to release energy
- • could provide energy for heating buildings
- • could provide energy for generating electricity
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what are the negative environmental effects of burning plastics to produce energy
- • increases CO2 emissions
- • increases global warming
- • could release toxic gases
- • does not conserve raw materials / crude oil
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suggest two pieces of evidence that may have led Wenger to purpose his hypothesis that continents move
- the continents of South Americaand Africa would have fittedtogether like a jigsaw
- there are matching / similar rocks/ fossils on the continents ofSouth America and Africa
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suggest why in 1920 , other scientist thought that Wegners hypothesis was wrong
- Wegener had no evidence to prove that continents can move
- and that a land bridge couldexplain the matching fossils on the continents of South America and Africa
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Copper is found in the Earths crust as an ore containing copper sulfide . Large areas of land , where this ore was once quarried , are contaiminated with low percentages of copper sulfide . Copper would be too expensive to extract from this contaminated land using the traditional method of quarrying then heating in a furnace . The percentage of copper ore in the contaminated land is low
it would be too expensive to extract from this land by the traditional method , explain why (1)
large amounts of energy would be needed to extract copper
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Copper is found in the Earths crust as an ore containing copper sulfide . Large areas of land , where this ore was once quarried , are contaiminated with low percentages of copper sulfide . Copper would be too expensive to extract from this contaminated land using the traditional method of quarrying then heating in a furnace . The percentage of copper ore in the contaminated land is low
extracting copper from this land by the traditional method would have a major environmental impact , give one reason why (1)
- any one from
- produces large amounts of solid waste
- atmospheric pollution from carbon dioxide and suplhur dioxide
- more lorries and more traffic
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it is possible to get copper from a solution of copper sulphate using scrap iron
It is economical to use scrap iron to get copper
give on ereason why (1)
iron is cheap
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why can iron be used to get copper from copper sulphate solution
iron displaces copper from the solution of its salts
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a new way to extract copper from land that contains low percentages of copper ore is phtomining . Phytominig uses plants . Plants are grown on this land and absorb copper compounds through their roots . Use this imformation to give two advantages of phtoming compared to the traditional method (2)
- any two from:
- • less expensive/energy toextract the small amountsof copper
- • plants will remove carbondioxide from theatmosphere as they grow
- • can release energy whenplants are burned
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a new way to extract copper from land that contains low percentages of copper ore is phtomining . Phytominig uses plants . Plants are grown on this land and absorb copper compounds through their roots . Use this information to suggest one disadvanatge of phytomining compared to the traditional method (1)
not continuous as it takes a long time for plants to grow
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hydrocarbon J burns completely in oxygen to produce carbon dioxide and water vapour
2C8H18 + 25O2 ===> 16CO2 + H2O
When 114g of hydrocarbon J burns completely in 400g of oxygen it produces 162g of water vapour and 352g of carbon dioxide
the mass of carbon dioxide produced is greater than the 114g of hydrocarbon J that was burned , explain why (2)
because 2 molecules ofhydrocarbon J had 25 moleculesof oxygen added
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process 1
fermentation of sugar solution by yeast in a reaction vessel. the reaction vessel has to be emptied , cleaned and refilled every few days. The process produces 15% ethanol solution in water
process 2
reaction of ethene (from crude oil) with steam in a reactor . The reaction is only stopped if there is a fault in the reactor . The process produces 100% ethanol
give one advantage that process 1 has over process 2 (1)
raw materials are renewable
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process 1 fermentation of sugar solution by yeast in a reaction vessel. the reaction vessel has to be emptied , cleaned and refilled every few days. The process produces 15% ethanol solution in waterprocess 2 reaction of ethene (from crude oil) with steam in a reactor . The reaction is only stopped if there is a fault in the reactor . The process produces 100% ethanol
what advantages to a manufacturer of ethanol does process 2 have over process 1 (2)
- alcohol does not need to be distilled
- process is continuous
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Air is a mixture of gases and contains various pollutants . The gases are useful and can be seperated by fractional distillation of liquid air . The table gives information about some of the gases in air
to seperate these gases :
the air is filtered
water is removed first
carbon dioixde is then removed by absorption
the gases remaining are compressed and cooled to -200°C
the air is filtered before the gases are sperated
suggest why
to removed the dust
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Air is a mixture of gases and contains various pollutants . The gases are useful and can be seperated by fractional distillation of liquid air . The table gives information about some of the gases in air
to seperate these gases :
the air is filtered
water is removed first
carbon dioixde is then removed by absorption
the gases remaining are compressed and cooled to -200°C
Water vapour and carbon dioxide are removed before the gases are compressed andcooled.Use the information in the table to suggest why.
because at 200°C both are solidsthis would therefore block pipes
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Air is a mixture of gases and contains various pollutants . The gases are useful and can be seperated by fractional distillation of liquid air . The table gives information about some of the gases in air
to seperate these gases :the air is filtered water is removed first carbon dioixde is then removed by absorption the gases remaining are compressed and cooled to -200°C
After the water and carbon dioxide have been removed, which gas stays liquid over thegreatest temperature range?
oxygen
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Air is a mixture of gases and contains various pollutants . The gases are useful and can be seperated by fractional distillation of liquid air . The table gives information about some of the gases in air
to seperate these gases :the air is filteredwater is removed firstcarbon dioixde is then removed by absorptionthe gases remaining are compressed and cooled to -200°C
After the water and carbon dioxide have been removed, the four gases that are left arecompressed and cooled to 200 oC.
Which gas does not liquefy?
helium
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Air is a mixture of gases and contains various pollutants . The gases are useful and can be seperated by fractional distillation of liquid air . The table gives information about some of the gases in air
to seperate these gases :the air is filteredwater is removed firstcarbon dioixde is then removed by absorptionthe gases remaining are compressed and cooled to -200°C
The three liquefied gases are then allowed to warm up.Give the order in which the three liquefied gases would vaporise
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reaction of ethene with steam to produce ethanol is known as
hydration
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Limestone contains the compound calcium carbonate , CaCO3 . Limestone is used to make cement in a rotary kiln . Name two main waste gases from this rotary kiln
- water vapour
- carbon dioxide
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columns used as supports for buildings can be made from materials such as limestone blocks or concrete . Why may people think that concrete is a better material for making a column (3)
- any three from
- • raw materials are abundant
- • can be reinforced (by steel rods) /strong(er) / supported (by steel rods)
- • concrete mixture can be poured /moulded / constructed on site
- • less reactive with acid rain /weathering / erosion
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columns used as supports for buildings can be made from materials such as limestone blocks or concrete . Why may people think that limestone is a better material for making a column (3)
- any three from
- • abundant / local
- • natural material or no ‘processing’needed
- • relatively easy to cut
- • appearance better
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copper oxide , CuO , is reduced using carbon . Describe and explain what happens in this reaction
- any two from:
- • heat (copper oxide with carbon)
- • oxygen is removed by carbon carbon dioxide is
- produced or carbon displaces copper
- • because carbon is more reactive than copper
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copper rich ores are running out
New ways of extracting copper from low grade ores are being researched . Recycling of copper may be better than extracting copper its ores explain why
- any three explanations from:
- • less acid rain (pollution)
- • copper reserves last longer / conserved or do not run out
- • energy for extraction (saved)or less energy required
- • less mining / quarrying
- • less waste (copper) / electrical appliances dumped or less landfill
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in general recyling is good because it
- saves resouces
- uses less energy
- usese less fossil fuels
- less pollution of carbon dioxide and sulphur dioxide into the atmosphere
- less waste rock
- less landfill
- however these points must be linked to the question being asked e.g. recycling copper conserves copper ore
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scientists cannot accurately predict when earthquakes will occur .
explain why (4)
- plate (boundaries)
- sudden movement / colliding
- or
- normally move a few centimetres per year
- convection currents / driven by heat from radioactive processes / decay
- the idea of uncertainty with an explanation eg scientists do not know (with any certainty)
- • what happens under the crust
- • where the forces / pressure are building up
- • we cannot measure the forces
- • when the forces reach their limit
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the ingredients of soft margerine include hydrogenated vegetable oil
why is hydrogenated vegetable oil used in soft margerine (1)
- any one from:
- • have a higher melting point than(vegetable) oil
- • are solid at (room temperature) /hardened / harder
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ethanol can be made using either sugar or alkanes such as the starting material . Evaluate the advantages and disadvantages of using these two starting materials to produce ethanol
**!!!!!!NO NEED TO COMPARE , THE QUESTION DOES NOT ASK YOU TO COMPARE , RTQ !!!!!!!**
- advantages of using sugar
- • country has no wealth to buy (large quantities of) crude oil
- • country has limited technological development or underdeveloped / third world country
- • able / suitable climate to grow sugar cane
- • enough land to grow sugar cane / land cannot be used to grow food /deforestation
- • sugar is a renewable source or crude oil is a non-renewable resource /finite resource / limited resources
- • CO2 / carbon neutral
- advantages of using alkanes:
- • economic costs are low
- • continuous process
- • country has large oil resources
- • country has oil refineries / cracking plants
- • very pure product
- • faster process
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