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All Saints Catholic School

Science Department

GCSE Revision Pack

C1 Prose, Application and Evaluation Questions

MARKSCHEME

M1. (a) Quality of written communicationfor any two ideas sensibly stated

1

any three from:

• plants take in (CO2)

accept photosynthesis uses (CO )

• converted to glucose / starch / carbohydratesignore carbon compounds by itself

• CO2 locked up in fossil fuelsaccept coal / oil / natural gas / methane for fossil fuels

• CO2 reacts with / dissolves (sea)wateraccept ocean removes CO2

• producing hydrogencarbonatesaccept carbonic acid

• producing carbonatesaccept named carbonates

• marine animals use carbonates to make shellsdo not accept bones

• forms sedimentary rocksaccept limestone / chalkaccept marbledo not accept sediments alone

3

(b) any two from:

• burning of fossil fuels or cars /industry / air travel / power stations

ignore increase in populationignore more use of electricity

• natural processes cannot absorb all the extra CO2

• deforestationaccept less photosynthesisignore volcanic activityaccept burn trees

2[6]

M2. (a) alkanes1

catalyst1

substances must be in the order shown

(b) many (ethenes/monomers)1

bond/join together1

allow ethenes / monomers bond / join together to form very large molecules for 2 marks

(c) Marks awarded for this answer will be determined by theQuality of Written Communication (QWC) as well as thestandard of the scientific response.

No relevant content.0 marks

There is a brief description of a positive and a negativeenvironmental impact involved with one or more methodsused to reduce the amount of plastic bags sent to landfill.

Level 1 (1–2 marks)

There is some description of both positive and negativeenvironmental impacts involved with at least 2 methodsused to reduce the amount of plastic bags sent to landfill.


There is a clear, balanced and detailed description of botha positive and a negative environmental impact of usingeach of the 3 methods used to reduce the amount of plasticbags sent to landfill.


examples of the chemistry points made in the response

reuse:reuse means less bags used so:

positive environmental impact

• saves raw materials / crude oil

• saves energy

• cuts down on CO2 emissions

• less global warming

negative environmental impact

• could cause litter

• could still be sent to landfill

recycle:bags bought can be recycled so:


• used to make new plastic bags / objects


• saves energy compared to producing plastic bagsfrom crude oil

• cuts down on CO2 emissions

• less global warming


• collection point sites cause an eyesore / litter problem

• transportation to recycling plant releases carbondioxide / causes global warming

burn:bags can be burned so:


• could provide energy for heating buildings

• could provide energy for generating electricity


• increases CO2 emissions

• increases global warming

• could release toxic gases

does not conserve raw materials / crude oil[10]

M3. (a) two sodium atoms (react)1

two (bonded) chlorine atoms (react)allow one chlorine molecule (reacts)

1

two sodium ions and two chloride ions (are produced)allow two molecules of sodium chloride (are produced) or two sodium chloride particles (produced)

1

(b) (i) (2x)max 1 if candidate changes the number of electrons in the first energy level / shell

8x (in second energy level / shell)1

1x (in outer energy level / shell)1

(ii) sodium has 1 electron in its outer energy level / shell

or

chlorine has 7 electrons in its outer energy level / shell1

[6]

M4. (a) (i) nitrogen1

(ii) carbon dioxide1

(iii) because water boils at 100°C and the temperatureon Venus is 460°C

1

therefore any water on the surface would boil to formsteam / water vapour / gas

1

(b) any three from:

• by photosynthesis

• by dissolving in oceans

• by the formation of (calcium) carbonate or limestone

• by the formation of oil or coalaccept by the formation of fossil fuels

3

(c) (i) 0.0317 (%)1

(ii) the percentage of carbon dioxide has increased1

(iii) any one from:

• burning of fossil fuels

• deforestation

• release of ‘locked up’ carbon dioxide1

[10]

M5. (a) 95% (1 mark for working)2

(b) Much less carbon dioxideMuch more nitrogen

2

(c) Plants take up CO2 plants give out oxygenwhen they die trap CO2 in rocks and fossil fuelsmethane and ammonia reacted with oxygennitrogen gas producedby reaction of oxygen and ammoniaand by denitryfying bacteriaformation of ozone layer

any 4 for 1 mark each4

[8]

M6. (a) coinage bronze1

(b) (97/100) × 2.5 = 2.425each line for 1 mark

2

(c) 3 points from the following:hard wearing,resistant to corrosion,low in reactivitylow densityabundant metal/low costshiny/appearancenot brittle

(Other properties of metals treated as neutral)3

[6]

M7. (a) (i) convection currentsin the mantle (1)driven by heat (1)from radioactive processes (1)

3

(ii) plates moving apartmagma rises to fill gapforms new rock

each for 1 mark3

(b) Rock further from ridge is oldermore time for sediment to settle

each for 1 mark2

[8]

M8. (a) catalyst or speeds up the reaction (owtte)accept lowers activation energy not just helps reaction to take placeignore increased surface area

1

(b) C8H18

allow H18C8

must be upper casedo not accept powers

1

(c) Bbecause it is a gas or because it has small molecules or because they are small

position and reason for markallow it has a lower / very low boiling point than Aignore references to solubilityaccept does not condensedo not accept light molecules or bubbles into Bdo not accept it is small

1

(d) breakdown of a substance (owtte)do not accept decompose unqualified

1

by the action of heat (owtte)1

(e) Quality of written communicationif the written communication makes sense and it is in context then award Q markQ Q

1

large to small molecules or scientific word that implies smaller,e.g. alkene / ethane / petrol

any name or formula of alkane / alkene smaller than decane1

either advantages of smaller molecules or disadvantages of larger moleculese.g. hydrocarbons with large molecules are limited in their usefulness

or converse for smaller molecules1

large hydrocarbon molecules do not ignite easily / do not flow easily /are not very volatile

or converse for smaller molecules

more large hydrocarbon molecules are produced than are neededor converse for smaller molecules

smaller molecules are useful as fuels

alkenes / products can be used to make polymers

(f) (fractional) distillationaccept fractionationaccept good description

do not accept just diagram1

[9]

M9. (a) (i) (healthiest oil is) sunflower (oil) or rapeseed (oil)

sunflower (oil) is healthiest because it has less saturatedfat than both olive (oil) and corn (oil)

or

rapeseed (oil) is healthiest because it has the lowestvalue of saturated fat compared with the other oils

1

sunflower (oil) is healthiest because it has the highestvalue of polyunsaturated fat compared with all the other oils

or

rapeseed (oil) is healthiest because it has morepolyunsaturated fat than both olive (oil) and corn (oil)

1

no mark for the choice of oilaccept the use of values from the table for these comparisons

(ii) no, because hydrogen adds to the unsaturated fator no, because hydrogen reduces the number ofcarbon–carbon double bonds

accept no because reacting with hydrogen increases number of single bonds

1

therefore there will be less polyunsaturated fataccept therefore there will be more saturated fat

1

(b) molecules in egg yolk act as emulsifiersaccept lecithin molecules act as emulsifiers

1

because molecules in egg yolk have a ‘head’ which dissolvesin / attracted to water

accept because molecules in egg yolk are hydrophilic1

because molecules in egg yolk have a ‘tail’ which dissolvesin / attracted to oil

accept because molecules in egg yolk are hydrophobic1

[7]

M10. (a) amount of CO2 (much) loweramount of O2 (much) higheramount of N2 (much) higher (owtte.)less other gases/less NH3/less CH4

any 2 for 2 marks2

(b) 4 points from:plants (evolved)/photosynthesis/algaetake in CO2

give out O2

water vapour condensedozone formed from oxygenless CO2 is produced now from volcanic activityCO2 from air trapped in sedimentary rocks or fossil fuelsnitrogen produced by bacteria/living organisms/microbes/decay of deadorganisms (not nitrifying bacteria, nitrogen fixing 4 bacteria)nitrogen produced by reaction of NH3 with O2/decomposition of NH3

nitrogen builds up because it is unreactive(Assume answer refers to today’s atmosphere)

any 4 for 1 mark each4

[6]

M11. (a) (i) nitrogen / N2

1

(ii) carbon dioxide / CO2

1

(b) (i) humans / scientists had not evolvedaccept it was billions / millions of years agoallow too long ago

1

(ii) temperature is above 100°C or any water would evaporate / boilaccept Venus is too hot

1

(c) any three from:

• used by plants

• used for photosynthesisaccept plants take in carbon dioxide and give out oxygen for the first two bullet points ie 2 marks

• dissolves in oceans / seasallow absorbs into oceans / seas

• used to form the shells / skeletons of marine organisms

• locked up as limestone / carbonates

• locked up as fossil fuels / oil / coal3

[7]

M12. (a) yes (there is the general trend) ‘as the iodine value increases the meltingpoint decreases’ or ‘as the hardness decreases the mp decreases’

accept converse statementdo not accept boiling point

orno melting points are in random order / go up and down

1

one specific use of comparative data from the table either showing thetrend or an anomaly

can be gained from yes or no answerignore bp

1

(b) the iodine turns colourless1

this would be difficult to see (if the oil was dark coloured)allow similar colour as iodine or iodine is brown

1

(c) (consumer may think that) the company (scientists) would be biased1

consumer more likely to trust independent scientistsallow independent scientists not biased

1

(d) add (measured amount of) hydrogenaccept hydrogenation

1

any two from:

• (nickel) catalyst

• hot / 60°C temperature

• hardenedaccept add a hard / hydrogenated fat / oil or make an emulsion

2[9]

M13. (a) (i) many ethene / molecules / monomersaccept double bonds open / break

1

join to form a long hydrocarbon / chain / large moleculeaccept addition polymerisationignore references to ethanecorrect equation gains 2 marks

1

(ii) (can be deformed but) return to their original shape (whenheated or cooled)

ignore ‘it remembers its shape’1

(iii) cross links / extra bonds in PEXaccept inter-molecular bondsignore inter-molecular forces

1

molecules / chains in PEX are held in positionaccept rigid structure

1

molecules / chains in PEX unable to slide past each other / moveit = PEX throughout

1

(b) any four from:

• less (hydrocarbon) fuels usedallow less energy

• less / no electrical energy usedallow no electrolysis

• reduce carbon / carbon dioxide emissionsallow less global warming

• reduce / no pollution by sulfur dioxide / acid rain

• continuous processallow less / no transportation

• conserve copper which is running out or only low-grade ores available

• reduce the amount of solid waste rock that needs to be disposedallow less waste

• reduce the need to dig large holes (to extract copper ores)allow less miningignore costs / sustainability / non-renewable

4[10]

M14. (a) (i) acid rainaccept consequences of acid rainallow asthma / bronchitisignore toxic gas

1

(ii) global dimmingaccept dimming alone

1

(b) (i) sustainable:

maximum two from:

• crops (that produce oil) can be grown in most places owtte

• renewable

• use less fossil fuels / diesel

• use (refined) waste oils

low pollution:

maximum two from:ignore references to CO2 here

• most emissions are lower or any two named emissions from CO / SO2 / PM10 are lower

• much / lot less SO2 emissions (than the others) owtte

• accept spillages / waste is biodegradable

• less new CO2 or (more) carbon neutral3

(ii) plants / photosynthesis use carbon (dioxide) from the air*1

it / biodiesel releases carbon (dioxide) from plants / crops / photosynthesis*(*) allow 1 mark for biodiesel is (more) carbon neutral

1

(fossil) diesel releases ‘locked up’ / new carbon (dioxide) / doesn’tabsorb CO2 / absorbed it millions of years ago

1[8]

M15. (a) any two from:

• naphtha has a different / low(er) boiling pointaccept different volatility

• condenses at a different temperature / height_ / place in the column / when it reaches it’s boiling point

• different size of molecules2

(b) (i) C10H22 → C6H14 + 2C2H4

allow multiples1

(ii) (hydrocarbon) heated / vapours1

(passed over a) catalyst / alumina / porous potignore other catalysts

1

(iii) it / ethene is unsaturated or decane and hexane / they are saturatedaccept decane and hexane are alkanes / CnH2n+2

or ethene is an alkene / CnH2n

or different homologous series / general formula1

ethene has a double (carbon carbon) bond or decane and hexane have onlysingle (carbon carbon) bonds

accept ethene has a reactive double (carbon carbon) bond for 2 marks

1

(c) all bonds drawn correctly

1

(d) economic argument against recycling

any one from:

• poly(ethene) / plastic must be collected / transported / sorted / washed

• this uses (fossil) fuels which are expensive1

environmental argument against recycling

any one from:

• uses (fossil) fuels that are non-renewable / formCO2 / CO / SO2 / NOx / particulates

ignore pollution / harmful gases / etc

• washing uses / pollutes water1

counter arguments

any two from:

• collect / transport alongside other waste

• use biofuels (instead of fossil)

• landfill is running out

• landfill destroys habitats

• incinerators are expensive to build


• saves energy needed to make new plastic

• incinerators may produce harmful substances

• incinerator ash goes to landfill

• poly(ethene) is non-biodegradable

• poly(ethene) can be made into other useful items

• more jobs / employment for people2

[12]

M16. (a) any two environmental problems with linked explanations

• global warming (1)accept effects of global warming

caused by (formation of) carbon dioxide / greenhouse gas (1)ignore greenhouse effect

• acid rain (1)accept effects of acid rainignore respiratory problems

caused by ( formation of) sulfur dioxide (1)accept sulfur oxideignore sulfuric acid

• global dimming (1)ignore respiratory problems

caused by ( formation of) particles / particulates / fires /smoke / carbon / pm 10 (1)

• scarring of landscape (1)

caused by mining / quarrying of coal (1)ignore ozone layer

max 4

(b) any three from:

• replant the trees / renewable / sustainableignore reusable

• carbon dioxide is used by the trees / photosynthesisaccept trees absorb carbon dioxide as they growdo not allow respiration

• it’s a (continuous carbon) cycleaccept ‘carbon dioxide goes back into the air’accept trees use CO2 which is released when trees are burnt

• no ‘new’ carbon (dioxide) is produced orno locked up carbon (dioxide) is released

accept no carbon (dioxide) from fossil fuels is produced3

[7]

M17. (a) (i) heat / evaporate the crude oil / change to gas or vapourdo not accept heat with catalyst

1

cool / condense (hydrocarbons)allow small molecules at top and / or large molecules at bottom

1

at different temperatures / boiling pointsif the answer describes cracking ‘ no marks

1

(ii) C4H10

1

(b) H H H │ │ │ H ─C ─ C ─ C ─ H │ │ │ H H H

1

(c) (i) C5 to C8 fraction are fuels or easier to burn or petrol (fraction)accept C21 to C24 fraction not useful as fuelsdo not accept produce more energy

1

(ii) C2H4

do not accept C4H8

1

(iii) any three from:

• use different / lighter crude oils

• develop markets for low demand fractions

• develop new techniques / equipment to use low demand fractionsas fuels

• cracking

• convert low demand fractions to high demand fractions or biggermolecules to smaller molecules

• develop alternative / bio fuels

do not accept price3

[10]

M18. (a) (i) Cu2S + 2O2 2CuO + SO2

accept fractions and multiple1

(ii) any two from:

• sulfur dioxide accept sulphur dioxide / sulphur oxide / SO2

• causes acid rain ignore other comments eg global warming / ozone / global dimming / greenhouse effect

• consequence of acid rain eg kills fish / plants2

(b) any two from:

• heat (copper oxide with carbon)

• oxygen is removed by carbonaccept copper (oxide) loses oxygen

orcarbon gains oxygenaccept carbon oxide

or

carbon monoxide / carbon dioxide is produced

or

carbon displaces copperaccept a correct word or balancedsymbol equation

• because carbon is more reactive than copperallow a correct comparison of reactivity

2

(c) (i) electrolysisaccept electroplating

1

(ii) (electrical) wiring / appliances / coins / pipes / cladding forbuildings / jewellery / making alloys

1

or

named alloys

(d) any three explanations from:

for recycling

• 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

against recycling

• collection problems

• transport problems

• difficult to separate copper from appliances

• energy used to melt the collected copperignore electrolysis / pollutionignore ideas about less machinery / plantignore idea of cost

3[10]

M19. (a) (i) by (fractional) distillationaccept a description of the distillation process (heat and how separation works) eg heat and condenseaccept boil / vapourise etc for heat

or

fractionation1

(ii) CO2

note the order of these products must be correct1

H2O wrong way round = 1 mark

1

(b) (i) (hexane) has been broken down (into smaller hydrocarbons / molecules)1

accept (thermal) decomposition / cracked / split / broken up owtte

(ii) H H │ │ C = C │ │ H H

accept CH2 = CH2

1

(iii) water / hydrogen oxide / steamaccept H2O

1

(c) candidates must include both sugar cane and crude oil in their evaluationand both an advantage and a disadvantage to gain full marks.if they do not then the maximum mark is three

any four from:

advantages of using sugar

• country has no wealth to buy (large quantities of) crude oilnot ‘expensive’ alone

• 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 process4

[10]

M20. Quality of written communication:for correct sequencing or linking of two ideas or two pointsannotate Q or Q

1

any three from:ignore superfluous statements

• B is least energy efficient in termsof cost (kJ per p), so A = C = D interms of cost or B is the mostexpensive in terms of energy

efficiencyowtte

accept B is poor value for money / B is most expensive one is insufficient for mark

• D is 1st, since gives only water as product or gives no harmfulproducts / gases or there are no pollutants owtte

• A is 2nd best, since produces CO2 owtte

• C is 3rd, since gives SO2 owtteif no other marks, then D A C B – based on energy per kJ per 100g only = 1 mark and Q mark if 2 ideas are linked

3[4]

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