Mark Scheme Q1. Answer D less than 0.5% A explanation linking any two of • dissolves /is absorbed (1) • in the oceans (1) • incorporated into marine organisms (1) • formed carbonate rocks (1) • increase in (green) plants/plants start growing • photosynthesi s /plants remove carbon dioxide traps heat
Acceptable answers reject references to plants respiring/breathing
Mark (1) (2)
reflects heat back to Earthreject references to the ozone layer
(1)
Acceptable answers
Mark
Q2. Question Number
Answer An explanation linking four of the following points • (during experiment) oxygen removed (1) • water level stops rising when all oxygen removed (1) • phosphorus oxide (formed) (1) • volume of air = 50 cm3 (1) • volume of oxygen = 50 - 40 cm3 (1) = 10 (cm3) • percentage of oxygen (in air) = 10 ÷ 50 × 100 (1) = 20%
(4)
Q3.
Q4.
Q5. Question Number (i) Question Number (ii) Question Number (iii)
Q6.
Answer
Acceptable answers
water vapour / steam condensed/ changed to liquid Answer
Allow steam cooled
(carbon dioxide) dissolved/ absorbed / trapped Answer
Ignore refs to plants/ rocks
A description including the following points • (primitive) plants (produce oxygen) (1) • (by) photosynthesis (1)
Allow named plants Reject answers involving respiration
Acceptable answers
Acceptable answers
Mark
(1) Mark
(1) Mark
(2)
Q7. Answer An explanation linking • volume of gas in bell jar decreases/water rises to fill the space (1) • oxygen is removed from the air (1) (amount of gases remaining) 79% (1)
= 790 (cm3)
Acceptable answers volume/amount of air decreases accept oxygen is used up
Mark
ecf for incorrect percentage of volume of gases remaining in M1 correct answer or valid calculation alone scores (2)
(2)
(2)
Q8. Answer (a)(i) (a)(ii)
(a)(iii)
(b)
(c)(i)
(c)(ii)
D less than 0.5% A explanation linking any two of • dissolves /is absorbed (1) • in the oceans (1) • incorporated into marine organisms (1) • formed carbonate rocks (1) • increase in (green) plants/plants start growing • photosynthesi s /plants remove carbon dioxide traps heat
A description to include • glowing splint (1) M1 • relights (1) M2 An explanation linking • volume of gas in bell jar decreases/water rises to fill the space (1) • oxygen is removed from the air (1) (amount of gases remaining) 79% (1)
= 790 (cm3) (d)
magnesium sulphate
Acceptable answers reject references to plants respiring/breathing
Mark (1) (2)
reflects heat back to Earthreject references to the ozone layer smouldering splint reject unlit splint ignore blown out splint M2 dependent on M1 but lighted splint burns brighter (2)
(1)
volume/amount of air decreases accept oxygen is used up
(2)
ecf for incorrect percentage of volume of gases remaining in M1 correct answer or valid calculation alone scores (2) accept magnesium
(2)
(2)
(1)
sulphate
Q9. Question Number (a)(i) Question Number (a)(ii) Question Number (a)(iii) Question Number (b) Question Number (c) Question Number (d)
Answer
Acceptable answers
Mark
photosynthesis Answer
Acceptable answers
(1) Mark
combustion Answer
Acceptable answers
(1) Mark
dissolving Answer
Acceptable answers
(1) Mark
(methane +) oxygen (1) → carbon dioxide + water (1) Answer C Answer An explanation linking the following • water vapour (1) • (cools and) condenses (1)
water + carbon dioxide Acceptable answers
(2) Mark
Acceptable answers
(1) Mark
(2)
Q10. Question Number (a)(i) Question Number (a)(ii)
Question Number (b)
Question Number (c)(i) Question Number (c)(ii)
Question Number (d)
Answer
Acceptable answers
Mark
D Answer
Acceptable answers
(1) Mark
An explanation linking three of the following points • dead animals / plants (1) • (dead animals / plants) become covered in sediment (1) • are squashed / crushed / compacted / pressured (as layers of sediment build up on top of one another) (1) • long time period (1) • fossils are caused by skeletons /bones / shells / remains (1) Answer An explanation linking the following points (limestone is subject to) • heat(1) • and pressure (1) (from the surrounding earth) Answer D Answer calcium carbonate → calcium oxide + carbon dioxide
Answer A description to include two of the following points • bubbles / fizzes (1) • steam (1) • solid swells (1) • (solid) crumbles / breaks up
Ignore heat Allow covered in sand / rock / limestone
Acceptable answers
(3) Mark
Ignore melting / magma / lava Ignore crushed Acceptable answers
(2) Mark
Acceptable answers
(1) Mark
Ignore heat in equation or on arrow Allow correct formulae instead of words e.g. CaCO3 → CaO + CO2 Acceptable answers
(1)
Mark
Ignore any colour changes Allow smoke Allow dissolves (2)
(1) • white powder (1) • (some) of the solid disappears (1) • water goes cloudy / milky (1)
Q11. Answer (a) (b)(i)
(b)(ii)
(b)(iii)
(c)
A chalk 1.10 (g) (1) or 1.1 (g) (1) or 2.50 – 1.40 (1) A suggestion including heat remaining solid/ heat it for longer / heat it again (1) mass after heating stays the same / gas does not turn limewater milky (1) or add acid (1) no effervescence (1) CaO + H2O → Ca(OH)2 LHS formulae correct (1) RHS formula correct (1) maximum 1 mark if any incorrect balancing initial total mass = 11.00 + 10.50 (1) = 21.50/21.5 (g) total mass remaining = 21.50 – 1.00 (1)
(d)
= 20.50/20.5 (g) marks are for the working An explanation linking two of neutralises / reacts with / removes / destroys/ gets rid of / takes in the (waste) gases(1) acid(ic) (gases) / carbon dioxide / sulfur dioxide / oxides of nitrogen (1)
Acceptable answers
Mark (1) (1)
Ignore reference to repeating the whole experiment again / heating a new sample of solid Allow add Universal Indicator and it stays red (after adding acid)
(2)
Allow Ca(HO)2 Allow multiples Reject obvious incorrect symbols and subscripts once only
(2)
20.50/20.5 (g) with no working (2) Allow 11.00 + 10.50 + 1.00 = 22.5/22.50 (g) (1) 22.5/22.50 (g) with no working (0) Allow correct working with incorrect answers
(2)
Ignore calcium carbonate is a base/alkali Allow stops (the waste gases) being released Allow reduces/prevents acid rain (1) Ignore toxic (gases) Allow acidic waste
(2)
Q12. Question Number (a) Question Number (b)(i) Question Number (b)(ii) Question Number (c)(i)
Question Number (c)(ii)
Question Number (c)(iii)
Answer
Acceptable answers
Mark
layers/layered Answer
Acceptable answers
(1) Mark
D Answer
Acceptable answers
(1) Mark
B Answer
Acceptable answers
(1) Mark
an explanation linking • (because) colour change / (changes from green to) black (1) • carbon dioxide (formed) (1) Answer
Acceptable answers
(2) Mark
took (only) 40 seconds changed colour first/fastest fastest time reacts the fastest second mark dependent on first mark but if no carbonate named can score second mark Acceptable answers
(1) Mark
an explanation linking the following points • copper (carbonate) (1) • because it produces gas / carbon dioxide fastest/in shortest time(1) Answer an explanation linking three of the following • (heat copper carbonate) in suitable container (which allows gas to be tested) (1) • suitable method of passing/collecting the gas e.g. bubble gas into / use of a delivery tube / collect gas in test tube (1) • limewater (1) • white (ppt)/ cloudy / milky(1)
marks could be gained from a diagram not just add gas to not blow ignore lighted/glowing splints dependent on correct use of limewater
(3)
Q13. Question Number (i)
Question Number (ii)
Question Number (iii)
Answer
Acceptable answers
Mark
an explanation linking • (because) colour change / (changes from green to) black (1) • carbon dioxide (formed) (1) Answer
Acceptable answers
(2) Mark
took (only) 40 seconds changed colour first/fastest fastest time reacts the fastest second mark dependent on first mark but if no carbonate named can score second mark Acceptable answers
(1) Mark
an explanation linking the following points • copper (carbonate) (1) • because it produces gas / carbon dioxide fastest/in shortest time(1) Answer an explanation linking three of the following • (heat copper carbonate) in suitable container (which allows gas to be tested) (1) • suitable method of passing/collecting the gas e.g. bubble gas into / use of a delivery tube / collect gas in test tube (1) • limewater (1) • white (ppt)/ cloudy / milky(1)
marks could be gained from a diagram not just add gas to not blow ignore lighted/glowing splints dependent on correct use of limewater
(3)
Q14. Indicative Content *(i)
Level 1
0 1-2
A description including some of the following Step A heat limestone strong heat / with roaring Bunsen flame thermally decompose limestone to form calcium oxide and carbon dioxide allow to cool word eqn: calcium carbonate → calcium oxide + carbon dioxide bal eqn: CaCO3 → CaO + CO2 Step B add water to calcium oxide calcium oxide swells/cracks/steams until in excess white solid dissolves in water filter mixture to remove unreacted calcium hydroxide colourless solution formed word eqn: calcium oxide + water → calcium hydroxide bal eqn: CaO + H2O → Ca(OH)2 No rewardable content
Mark
(6)
• a limited description e.g. strongly heat limestone • the answer communicates ideas using simple language and uses limited scientific terminology • spelling, punctuation and grammar are used with limited accuracy 2
3-4 • a simple description e.g. strongly heat limestone, then add water to the calcium oxide • the answer communicates ideas
showing some evidence of clarity and organisation and uses scientific terminology appropriately • spelling, punctuation and grammar are used with some accuracy 3
5-6 • a detailed description e.g. strongly heat limestone, carbon dioxide evolved, add water to the calcium oxide, colourless solution formed • the answer communicates ideas clearly and coherently uses a range of scientific terminology accurately • spelling, punctuation and grammar are used with few errors
Q15. Answer
Acceptable answers
An explanation linking two of layers / deposits of (1) sediment/sand/rock/ dead (sea) creatures (1) (sediment is ) squashed/crushed/c ompacted / pressurised (1) over (a long period of) time (1)
Mark (2)
Q16. Answer An explanation linking any three of the following • magma/lava/ molten rock (1) M1 • cools (1) M2 • (A cools) quickly to form small crystals (1) M3 • (B cools) slowly to form large crystals(1) M4
Acceptable answers If no reference to magma/lava/molten rock max 2 marks reference to reason for different rates of cooling e.g. (rock A forms) on surface/extrusive so small crystals e.g. (rock B forms) underground/intrusiv e so large crystals
Mark (3)
Q17.
QWC
*
Indicative Content
Mark
An explanation including some of the following calcium carbonate/limeston e • for buildings • making roads • treating acid soil/ treating acid lakes • in power station chimneys • making cement • making concrete and mortar • making glass • extracting iron • heating (to make calcium oxide) • making sodium carbonate • as a filler in plastics and paper • in paints • toothpaste • gravestones • statues, decorative stonework • indigestion remedies • railway ballast • bread makingcalcium oxide • treating acid soil • in power station chimneys • making calcium hydroxide (when water added)calcium hydroxide • treating acid soil
(6)
Level 1
0 1-2
• making limewater No rewardable content • a limited description (only one product need be mentioned) e.g. limestone is used to build houses and to make cement. • the answer communicates ideas using simple language and uses limited scientific terminology • spelling, punctuation and grammar are used with limited accuracy
2
3-4 • a simple description (limited mention of two products or more developed mention of one) e.g. limestone is used to make cement, glass and (in the manufacture of) iron where it forms slag. • the answer communicates ideas showing some evidence of clarity and organisation and uses scientific terminology appropriately • spelling, punctuation and grammar are used with some accuracy
3
5-6 • a detailed description (limited mention of all three products or developed mention of one and limited mention of one) e.g. limestone is used for roads and to make cement: it is also heated to make calcium oxide which is used to treat acid soil. • the answer communicates ideas clearly and coherently uses a range of scientific terminology accurately • spelling, punctuation and grammar are used with few errors
Q18. Question Number QWC
Indicative Content *
Level 1
0 1-2
2
3-4
3
5-6
Mark
A description including some of the following points: • formed from sediments / shells • sediments fall to the bottom of the sea • layers of sediment build up on top of one another • over (very) long time period • rock formed / compaction • (caused by)pressure (from the layers above and minerals) • (cause) the sediment to ‘stick together’ • (to form)layers • rock movement/change in sea level • (more recently) rock has been weathered / eroded (by sea) • because it is a soft rock (6) No rewardable content • a limited description e.g. sediments fell to the bottom of the sea in layers • the answer communicates ideas using simple language and uses limited scientific terminology • spelling, punctuation and grammar are used with limited accuracy • a simple description e.g. limestone is formed from sediments building up at the bottom of the sea in layers and is squashed to form rock • the answer communicates ideas showing some evidence of clarity and organisation and uses scientific terminology appropriately • spelling, punctuation and grammar are used with some accuracy • a detailed description e.g. Sediments fall to the bottom of the sea and are compacted to form layers of rock , more rock builds up on top. Limestone is a soft rock and has been eroded by the sea. • the answer communicates ideas clearly and coherently uses a range of scientific terminology accurately • spelling, punctuation and
grammar are used with few errors Q19. Answer B
Acceptable answers
(increases noise)
Mark (1)
Q20. Answer (a) (b)(i)
(b)(ii)
(c)(i) (c)(ii)
(c)(iii)
B (increases noise) An explanation linking the following • break down (of a compound) (1) • heat / high temperature (makes process happen) (1) 56 (kg)
Marble An explanation linking • heat/high temp (1) • (high) pressure / compressed (1) Igneous
Acceptable answers
Mark (1) (2)
break up/ split up [ignore decompose]
Accept 100-44 if not worked out if units given must be kg
(1)
(1) (2) Reject if melting
(1)
Q21. Question Number
Answer
Acceptable answers
An explanation linking the following points (limestone is subject to) • heat(1) • and pressure (1) (from the surrounding earth)
Ignore melting / magma / lava Ignore crushed
Mark
(2)
Q22. Answer (a)
(b)
(c)
QWC
Acceptable answers
an explanation linking any three of • (removes waste) gases that are acidic • contain sulfur dioxide (1) • (produced from) sulfur impurities in coal (1) • (limestone/cal cium carbonate) reacts with/neutralises (gases)(1) CaCO3 → CaO + CO2 • reactant formula (1) • product formulae (1) C – the lump of calcium oxide cools down
*(d)
Mark (3)
limestone/calciu m carbonate is a base (1) ignore limestone/calcium carbonate is an alkali
max 1 if any incorrect attempt to balance reject incorrect use of cases and non-subscripts
(2)
(1) Indicative Content
Mark
An explanation linking some of the following limestone • formed from sediments/shells • sediments fall to bottom of sea • layers of sediments build up • long time period • compaction • by pressure • rocks appear out of the seagranite • magma /molten rock • forced up • cools • solidifies
(6)
Level 1
0 1-2
• intrusive rock • forms crystalsmarble • limestone changed/metamorph osed • by heat • (from) magma/molten rock • and pressure No rewardable content • a limited explanation e.g. limestone formed from sediments on the sea bed. • the answer communicates ideas using simple language and uses limited scientific terminology • spelling, punctuation and grammar are used with limited accuracy
2
3-4 • a simple explanation e.g sediments compacted to form limestone which is changed by heat and pressure into marble. • the answer communicates ideas showing some evidence of clarity and organisation and uses scientific terminology appropriately • spelling, punctuation and grammar are used with some accuracy
3
5-6 • a detailed explanation e.g. limestone formed from sediments . Molten rock /magma cools to form granite. The heat and pressure change the limestone into marble. • the answer communicates ideas clearly and coherently uses a range of scientific terminology accurately • spelling, punctuation and grammar are used with few errors
Q23. Answer (a) (b)(i)
(b)(ii)
(c)(i)
(c)(ii)
D a salt and water only A description including two of • (acid) colourless (liquid/solution) (1) • (carbonate) green (solid) (1) • disappears (1) • effervesces/fizzes/bu bbles (1) • blue (solution) (forms) (1) CuCO3 + 2HNO3 → Cu(NO3)2 + H20 + CO2 reactants (1) products (1) balancing of correct formulae (1) An explanation linking • decompositio n (of compound/substanc e) (1) M1
• (by) (direct electric) current (1) M2 A description linking • glowing splint (1) M1 • relights (1) M2
Acceptable answers
Mark (1) (2)
Ignore clear dissolves Ignore gas/carbon dioxide given off
multiples
(3)
splitting up/breaking down/breaking up (of compound/substanc e) Reject splitting of atoms/elements for M1 Ignore separating (by) electricity/electrical energy/direct current Reject alternating current/ac smouldering splint Reject unlit (splint) Ignore blown out (splint) M2 dependent on M1 but lighted splint burns brighter = 2
(2)
(2)
Q24.
Q25. Answer (a)(i) (a)(ii) (b)
(c)(i) (c)(ii)
(d)(i)
(d)(ii)
break down food / (help) digestion D (to neutralise excess acid) zinc oxide + sulfuric acid zinc sulfate + water any 3 correct – 1 mark all 4 correct (and no additional substances) – 2 marks A (electrolysis) A description including • lighted splint / ignite gas (1) • (squeaky) pop (1) An explanation linking • chlorine toxic / poisonous (1) • fume cupboard removes gas / OWTTE (1) PVC / poly(chloroethene)
Acceptable answers
Mark (1) (1)
Allow fully correct balanced equation for 2
(2)
(1) (2)
ignore harmful etc
(2)
Polychloroethene / polychlorethene reject poly(chloroethane)
(1)
Q26. Question Number (a)(i) Question Number (a)(ii) Question Number (a)(iii)
Question Number (b)(i) Question Number (b)(ii)
Question Number (b)(iii)
Answer
Acceptable answers
Mark
• to digest food (1) • to kill bacteria (1) Answer
Acceptable answers
(2) Mark
D Answer
Acceptable answers
(1) Mark
Acceptable answers
(2) Mark
D Answer
Acceptable answers
(1) Mark
A description including the following points • damp blue litmus paper (into gas) (1) • (turns) red then bleached (1) Answer
Acceptable answers
(2) Mark
magnesium carbonate + hydrochloric acid → magnesium chloride + water + carbon dioxide (2) if equation incorrect / incomplete allow magnesium chloride as product (1) Answer
An explanation linking the following points • chlorine toxic (1) • (therefore) gas must not escape (1)
Accepthydrogen flammable (therefore) no naked flames (2)
Q27. Question Number (a) Question Number (b)
Question Number (c)
Question Number QWC
Answer
Acceptable answers
Mark
D Answer
Acceptable answers
(1) Mark
an explanation linking the following • decomposition /break down of compound / substance / electrolyte(1) • using electricity / electrical energy / d.c supply (1) Answer
do not allow first point if mention of covalent molecule, substance etc. note examples in spec are water and Hydrochloric acid
Cl2 + 2NaOH → NaOCl + NaCl + H2O • reactant formulae (1) • product formulae (1) • balancing correct formulae (1)
allow multiples
*(d)
Acceptable answers
(2) Mark
Indicative Content
(3) Mark
an explanation linking some of the following: cause of acid rain• burning sulfur • produces sulfur dioxide • escapes into atmosphere • dissolves in rain water • forming acidic solution / sulfurous / sulfuric acid • falls to the ground as acid rain effect of acid rain• acidification of lakes • kills fish • kills trees / forests • damage / erosion of stonework reduction of damage• calcium carbonate • from limestone • may be converted into calcium hydroxide
(6)
Level 1
0 1-2
2
3-4
3
5-6
• waste gases from power stations • passed through carbonate or hydroxide • removing sulfur dioxide some of the above points could be made using word or symbol equations No rewardable content • a limited explanation e.g. when fuels burn the sulfur makes sulfur dioxide that causes acid rain • the answer communicates ideas using simple language and uses limited scientific terminology • spelling, punctuation and grammar are used with limited accuracy • a simple explanantion e.g. when the fuel burns, sulfur impurities make sulfur dioxide which gives acid rain. Acid rain reacts with limestone statues. • the answer communicates ideas showing some evidence of clarity and organisation and uses scientific terminology appropriately • spelling, punctuation and grammar are used with some accuracy • a detailed explanation e.g. when fuels burn, any sulfur impurities burn to make sulfur dioxide which dissolves in rain to make it more acidic. This rain corrodes metals and limestone. The problem can be solved by removing sulfur from the fuels • the answer communicates ideas clearly and coherently uses a range of scientific terminology accurately • spelling, punctuation and grammar are used with few errors
Q28. Question Number (i) Question Number (ii)
Question Number (iii)
Answer
Acceptable answers
Mark
D Answer
Acceptable answers
(1) Mark
A description including the following points • damp blue litmus paper (into gas) (1) • (turns) red then bleached (1) Answer
Acceptable answers
(2) Mark
An explanation linking the following points • chlorine toxic (1) • (therefore) gas must not escape (1)
Accepthydrogen flammable (therefore) no naked flames
Answer
Acceptable answers
2H2O → 2H2 + O2 • reactant formula (1) • product formulae (1) • balancing correct formulae (1) Answer
Allow 1 mark for 2H2O → 2H2 + O2 Ignore state symbols Ignore word equations
(2)
Q29. Question Number (i)
Question Number (ii)
Question Number (iii)
A description including the following: • lighted splint / ignite gas / gas burns( 1) • with (squeaky) pop (if air present) (1) Answer A description including the following • glowing splint (1) • relights (1)
Mark
Acceptable answers
(3) Mark
Acceptable answers
(2) Mark
smouldering splint Ignore blown out splint lighted splint burns brighter = 2 (2)
Q30. Question Number QWC
Indicative Content *
Level 1
0 1-2
2
3-4
3
5-6
Mark
an explanation linking some of the following points (could be in diagram) • put acid in container • attach power supply/electricity supply • use direct current • test tube inverted over electrode(s) • bubbles seen • one product hydrogen • one product chlorine • bleached litmus • relevant safety precaution (6) No rewardable content • a limited explanation e.g. one correct statement eg pass electricity (through acid) • the answer communicates ideas using simple language and uses limited scientific terminology • spelling, punctuation and grammar are used with limited accuracy • a simple explanation e.g pass electricty through the acid and hydrogen or chlorine formed • the answer communicates ideas showing some evidence of clarity and organisation and uses scientific terminology appropriately • spelling, punctuation and grammar are used with some accuracy • a detailed explanatione.eg. electricity is passed through the acid, hydrogen and chlorine are formed • eg puts acid in container, uses direct current, puts test tube over electrode to collect chlorine • the answer communicates ideas clearly and coherently uses a range of scientific terminology accurately • spelling, punctuation and grammar are used with few errors
Q31. Answer an explanation linking the following • decompositio n (of compound/substanc e /electrolyte)(1) • using (direct) current (1)
• (damp blue) litmus (paper) (1) • (turns red then) bleaches / goes white (1)
poly(chloroethene)
Acceptable answers splitting up/breaking down/breaking up ignore separating reject splitting of atoms/elements/mol ecules for M1 using electrical energy /electricity reject alternating current/ac allow bleaches indicator for 1 mark ignore indicator goes lighter ignore smells of chlorine/swimming pools ignore any incorrect middle colour mentioned use of suitable named indicator with correct result e.g. (damp) universal indicator paper (1) (turns red then) bleaches (1) starchiodide paper(1) turns blue-black(1) PVC/polyvinylchlorid e/
Mark (2)
(2)
polychloroethene/pol y(chlorethene) (1)
Q32. Answer (i)
An explanation linking • decompositio n (of compound/substanc
Acceptable answers splitting up/breaking down/breaking up (of compound/substanc e) Reject splitting of
Mark (2)
e) (1) M1
(ii)
• (by) (direct electric) current (1) M2 A description linking • glowing splint (1) M1 • relights (1) M2
atoms/elements for M1 Ignore separating (by) electricity/electrical energy/direct current Reject alternating current/ac smouldering splint Reject unlit (splint) Ignore blown out (splint) M2 dependent on M1 but lighted splint burns brighter = 2
(2)
Q33. Answer (a)(i)
an explanation linking the following • decompositio n (of compound/substanc e /electrolyte)(1) • using (direct) current (1)
(a)(ii) • (damp blue) litmus (paper) (1) • (turns red then) bleaches / goes white (1)
(a) (iii)
poly(chloroethene)
Acceptable answers splitting up/breaking down/breaking up ignore separating reject splitting of atoms/elements/mol ecules for M1 using electrical energy /electricity reject alternating current/ac allow bleaches indicator for 1 mark ignore indicator goes lighter ignore smells of chlorine/swimming pools ignore any incorrect middle colour mentioned use of suitable named indicator with correct result e.g. (damp) universal indicator paper (1) (turns red then) bleaches (1) starchiodide paper(1) turns blue-black(1) PVC/polyvinylchlorid e/
Mark (2)
(2)
polychloroethene/pol y(chlorethene) (b)(i) (b)(ii) (b)(iii)
D AgCl(s) same/no change HCl + AgNO3 → AgCl + HNO3 • reactant formulae (1) • product formulae (1)
Ag+ + Cl- → AgCl max 1 if any incorrect attempt to balance reject incorrect use of cases and nonsubscripts
(1) (1) (1) (2)
Q34.
Q35. Question Number (a)(i)
Question Number (a)(ii)
Question Number (a)(iii)
Question Number (b)(i) Question Number (b)(ii)
Question Number (c)
Answer
Acceptable answers
2H2O → 2H2 + O2 • reactant formula (1) • product formulae (1) • balancing correct formulae (1) Answer
Allow 1 mark for 2H2O → 2H2 + O2 Ignore state symbols Ignore word equations
A description including the following: • lighted splint / ignite gas / gas burns( 1) • with (squeaky) pop (if air present) (1) Answer A description including the following • glowing splint (1) • relights (1) Answer B Answer
Mark
Acceptable answers
(3) Mark
Acceptable answers
(2) Mark
smouldering splint Ignore blown out splint lighted splint burns brighter = 2 Acceptable answers
(2) Mark
Acceptable answers
(1) Mark
use a fume cupboard/open all the windows /(good) ventilation/wear a gas mask Answer
Ignore do not breathe in
Acceptable answers
(1) Mark
hydrochloric (acid)
Ignore HCl
(1)
Answer
Acceptable answers
Mark
an explanation linking one of the following pairs • when bent / deformed (1) • shape memory alloys return to their original shape (1) OR • shape memory
must refer to metal’s shape being changed i.e. ignore “broke”, “sat on etc.”
Q36. Question Number
(2)
alloys return to their original shape (1) • (but) other alloys stay deformed (1) Q37.
Q38. Question Number (i) Question Number (ii)
Answer
Acceptable answers
Mark
D Answer
Acceptable answers
(1) Mark
An explanation linking two of the following • (aluminium) more reactive (1) • forms more stable compounds (1) • more difficult to remove oxygen /split (compound) (1) • electrolysis is more powerful method of reduction (1)
too reactive/above carbon/higher up in reactivity series forms compounds with stronger bonds carbon cannot remove oxygen/displace aluminium
Answer
Acceptable answers
(2)
Q39.
An explanation linking • mixture of a metal (1) • with another metal or carbon (1)
Mark (2)
Do not allow combining / bonding / joining etc instead of mixture allow specific examples
Q40. Answer (a)
(b) (c)(i)
(c)(ii)
• tin more expensive/costs more (than aluminium/steel) ORA (1) • amount of tin in Earth smaller (than aluminium/steel) ORA (1) C - reduction an explanation linking the following • a mixture of (1) • metals (1) an explanation linking any three of • in pure metal /aluminium atoms are all same size (1) • in pure metal /aluminium layers/sheets/atoms slide/slip/move (over one another) easily(1) • magnesium atoms larger (1) • disrupt layers/structure/arran geme nt of aluminium atoms (1) • prevent layers/sheets/atoms slip/slide/move (1)
Acceptable answers rarer
reject compound ignore combined/joined specific examples reject reference to non-metals metals melted together (2) ions or particles for atoms reject molecules once only different sized particles lock/hold/jam layers together
Mark (2)
(1) (2)
(3)
Q41. Question Number (i) Question Number (ii)
Question Number (iii)
Q42.
Answer
Acceptable answers
Mark
C Answer
Acceptable answers
(1) Mark
An explanation linking any two of the following points • decrease (in mass)(1) • (because) gas given off (1) • (gas is) carbon dioxide (1) Answer
Acceptable answers
(2) Mark
An explanation linking the following points • copper oxide/ copper in copper oxide (1) • (as) loses oxygen (1)
(2)
Q43. Answer An explanation linking three of atoms of gold all the same (size) (1) in pure gold layers/rows/sheets/li nes of the gold / metal atoms slide over each other (when force is applied) (1) copper atoms are smaller / different size (1) (copper atoms) disrupt / distort /disturb the structure / layers (1) stops layers/rows/sheets/li nes of gold atoms from sliding over each other (1)
Acceptable answers Reject the use of the word molecule once only Allow particles If layers/rows/sheets/li nes is omitted twice, you can award one mark.
Mark
Acceptable answers
Mark
(3)
Q44. Answer An explanation linking two of • unreactive/inert (1) • does not corrode (1) • malleable (1) • ductile (1) • scarce / valuable / expensive (1) • appropriate melting point (1) • (so stays) shiny /attractive (1)
(2) Ignore does not rust
Q45. Question Number QWC
Indicative Content *
Level 1
0 1-2
2
3-4
Mark
A description including some of the following points aluminium• alumini um used in aircraft • aluminium alloy remains low density • aluminium alloy is stronger gold• gold used in rings and jewellery • pure gold is soft • alloy is harder • smaller the carats / the less gold present, the stronger the alloy • alloy cheaper than pure metal nitinol• nitinol is alloy of nickel and titanium • shape memory alloy • smart material • regains shape after distortion • used e.g. in spectacle frames • alloys generally stronger than pure metals • (because) in pure metals layers of particles slide over one another • different sized particles of other metal in alloy • disrupt / obstruct sliding (6) No rewardable content • a limited description including at least four relevant points • the answer communicates ideas using simple language and uses limited scientific terminology • spelling, punctuation and grammar are used with limited accuracy • a description including at least five relevant points about the uses of at least two metals / at least three relevant points about the uses of any of the metals, with an explanation making at least one point about
3
5-6
structure • the answer communicates ideas showing some evidence of clarity and organisation and uses scientific terminology appropriately • spelling, punctuation and grammar are used with some accuracy • a detailed description including at least seven relevant points about the use of at least two metals, with an explanation making at least two points about the structure • the answer communicates ideas clearly and coherently uses a range of scientific terminology accurately • spelling, punctuation and grammar are used with few errors
Q46. Answer an explanation linking the following • a mixture of (1) • metals (1) an explanation linking any three of • in pure metal /aluminium atoms are all same size (1) • in pure metal /aluminium layers/sheets/atoms slide/slip/move (over one another) easily(1) • magnesium atoms larger (1) • disrupt layers/structure/arran geme nt of aluminium atoms (1) • prevent layers/sheets/atoms slip/slide/move (1)
Acceptable answers reject compound ignore combined/joined specific examples reject reference to non-metals metals melted together (2) ions or particles for atoms reject molecules once only different sized particles lock/hold/jam layers together
Mark
Acceptable answers rarer
Mark
(2)
(3)
Q47. Answer
• tin more expensive/costs more (than aluminium/steel) ORA (1) • amount of tin in Earth smaller (than aluminium/steel) ORA (1)
(2)
Q48. Answer (a)
(b) (c)
QWC
An explanation including two of • does not corrode/tarnish (1) M1 • unreactive (1) M2
• shiny/lustrous (1) M3 • malleable/eas ily shaped (1) M4 • scarce/expen sive/maintain s its value (1) M5 C 24 carat An explanation linking three of • (gold) atoms all same size (1) M1 • layers/sheets (of atoms) slide/slip/move M2 (over one another easily) (1) • (alloy) added metals atoms are different size (1) M3 • disruptlayers/ structure/ arrangement of gold atoms (1) M4 • prevent layers/atoms slide/slip/move (1) M5
*(d)
Acceptable answers Ignore does not rust does not react with oxygen and/or water Ignore least reactive/less reactive/not very reactive/reacts very slowly attractive Ignore soft/strong valuable
Marks can be gained from suitable diagrams No mention of layers/sheets in answer maximum 2 marks Accept particles/ions for atoms reject molecules (once only) lock/hold layers/atoms together
Mark (2)
(1) (3)
Indicative Content
Mark
An explanation including some of the following points reactivity series • aluminium more reactive than
(6)
Level 1
0 1-2
iron/aluminium higher than iron in reactivity series • aluminium forms stronger bonds with oxygen than iron does • aluminium oxide more stable (to decomposition) than iron oxide • aluminium more reactive than carbon/aluminium higher than carbon in reactivity seriescost • electrolysis/el ectricity (more) expensive (than heating with carbon) • heating with carbon is (relatively) cheap methodIron • carbon more reactive than iron/iron less reactive than carbon • iron oxide reduced • by heating with carbon • no need to use (expensive) electrolysisAluminiu m • aluminium oxide difficult to reduce • aluminium oxide cannot be reduced by (heating with) carbon • (cheaper) reduction with carbon does not work • need more powerful method of reduction • therefore must use electrolysis No rewardable content
• a limited description e.g. aluminium is very reactive e.g. aluminium extracted by electrolysis e.g. iron extracted using carbon e.g. costs more to extract aluminium • the answer communicates ideas using simple language and uses limited scientific terminology • spelling, punctuation and grammar are used with limited accuracy 2
3-4 • a simple description containing two statements referring to one method of extraction and a cost e.g. iron is extracted by heating iron oxide with carbon and this is cheaper OR the relative reactivity of one metal and a method of extraction e.g. aluminium is extracted by electrolysis. Aluminium is more reactive than iron (has made a comparison in reactivity) OR the relative reactivity of one metal and reference to cost e.g. aluminium is a more reactive metal and so is expensive to extract • the answer communicates ideas showing some evidence of clarity and organisation and uses scientific terminology appropriately • spelling, punctuation and grammar are used with some accuracy
3
5-6 • a detailed description containing at least three statements referring to relative reactivity of both metals, a method of extraction of at least one metal, and a cost reference e.g. aluminium is more reactive than iron so is extracted by electrolysis which is expensive • the answer communicates ideas clearly and coherently uses a range of scientific terminology accurately • spelling, punctuation and grammar are used with few errors
Q49. Question Number (a) Question Number (b) Question Number (c)(i)
Answer
Acceptable answers
Mark
(electrical) wiring Answer
Acceptable answers
(1) Mark
ore(s) Answer
Acceptable answers
(1) Mark
Question Number (c)(ii)
Answer
Reject reasons for copper or aluminium being the best metal to use MAXIMUM (1) if include poor resistance to corrosion and/or good conductor of electricity Acceptable answers
(2) Mark
Question Number QWC
An explanation linking two of the following points • strength / strong (1) • (to) withstand forces/hold up heavy cable (1) • low cost / cheap(1)
An explanation linking two from the following points • low density/light(1) • (so) fewer pylons needed / easier to support (1) • (therefore) low cost/cheap(1)
*(d)
Ignore any additional properties mentioned in answer
Indicative Content
(2) Mark
An explanation including some of the following points • copper used for pipes / wiring / vehicles • aluminium used for cans / wires / alloys • steel used for bridges / making stainless steel cutlery etc • recycled metals can be made into something useful • saves (finite) resources / stops the metal (ore) running out • less damage to environment by mining/quarrying • less waste
(6)
Level 1
0 1-2
2
3-4
3
5-6
• landfill sites will not fill up as quickly • (some) metals do not corrode /break down • (so)remain a long time in landfill • so fewer landfills needed • less damage to environment from waste • copper waste toxic • less expensive than electrolysis No rewardable content • a limited explanation e.g. if we throw the metals away they will run out / if we recycle, the metal can be used for something else • the answer communicates ideas using simple language and uses limited scientific terminology • spelling, punctuation and grammar are used with limited accuracy • a simple explanation e.g. throwing the metals away will fill up landfill sites, recycling will save mining for new ore • the answer communicates ideas showing some evidence of clarity and organisation and uses scientific terminology appropriately • spelling punctuation and grammar are used with some accuracy • a detailed explanation e.g. Recycled metals can be made into other useful products. Metals in landfill sites do not corrode quickly. If new ore is used deposits will eventually run out. • the answer communicates ideas clearly and coherently uses a range of scientific terminology accurately • spelling, punctuation and grammar are used with few errors
Q50. Answer (a)(i) (b)(i) (b)(ii) (b)(iii)
(c)
A gold carbon dioxide (1) iron (1) loss of oxygen / oxygen is removed
Acceptable answers carbon monoxide
Mark (1) (2)
gain of electrons ignore oxide removal
(1)
An explanation linking two of aluminium is high in reactivity (1) aluminium oxide is stable (1) (needs) powerful means (of reduction) / hard to extract (1) use electricity (1) aluminium not reduced by carbon (1) An explanation linking two of conserves resources/ores (1) reduces waste material (from extraction) (1) less damage to landscape / habitats (1) reduces landfill (1) less copper/metal goes to waste (1)
Allow higher than carbon carbon is not reactive enough accept other (cheaper) methods if qualified.
(2)
will not run out of metals / copper accept cost/energy/pollution only if qualified (1) e.g. less energy to recycle than to extract from ore
(2)
Answer
Acceptable answers Ignore C
Mark
Allow any phonetically correct spelling oxygen moved /transferred from lead to carbon (2) oxide transferred gets no credit
(1)
Q51.
(a)(i) (a)(ii) (b)
Carbon Exact spelling only Electricity An explanation linking • lead oxide loses oxygen(1) • carbon gains oxygen (1)
(1)
(2)
(c)
(d) (e) (i) (e)(ii)
An explanation linking two of • both good conductors of electricity (1) • (aluminium) has low(er) density (1) • so cables lighter • (therefore) fewer pylons (1) D more resistant to corrosion 62.5 - 63 Allow anywhere in this range A description including • decreases first (1) • then increases (1)
Allow light(er)
(2) (1) (1) "decreases then increases" scores 2 decreases or increases alone scores 0
(2)
Q52. Answer (a)
(good) conductor (of electricity) / flexible / malleable / ductile / unreactive
(b) (c)
D (are stronger) An explanation linking two of • unreactive/inert (1) • does not corrode (1) • malleable (1) • ductile (1) • scarce / valuable / expensive (1) • appropriate melting point (1) • (so stays) shiny /attractive (1) An explanation linking • mixture of a metal (1) • with another metal or carbon (1)
(d)
(e)
(f)
iron oxide + carbon monoxide iron + carbon dioxide reactants (1) products (1) An explanation linking • preserves supplies (1) • as new ore not needed (1)OR • fewer quarries / mines / eyesores (1) • because ore does not have to be dug up (1)OR • iron objects last a long time (1) • so would fill up landfill sites
Acceptable answers Allow explanations eg 'allows electricity to pass through'. Copper does not rust is not accepted
Mark (1)
(1) (2) Ignore does not rust
(2) Do not allow combining / bonding / joining etc instead of mixture allow specific examples Allow fully balanced symbol equation for 2
Ignore references to cost
(2)
(2)
(1)OR • because just has to be melted (1)OR • saves energy (1) • therefore less carbon dioxide released (1)
Q53. Question Number
Answer A description including three of the following, with a maximum of two from either group of three • reduction is the loss of oxygen (1) • copper(oxide) loses oxygen (1) • (hence) copper (oxide) is reduced (1) OR • oxidation is the gain of oxygen (1) • hydrogen gains oxygen (1) • (hence) hydrogen is oxidised (1)
Acceptable answers
Mark
(3)
Q54. Question Number QWC
Indicative Content *
Level 1
0 1-2
2
3-4
Mark
An explanation linking some of the following points Fuel A • very easy to light • not smoky • gives off least heat • gas so harder to store Fuel B • very easy to light • not smoky • doesn’t give off most heat • liquid so easy to store Fuel C • easy to light, but harder than A or B • little bit of smoke • doesn’t give off most heat • liquid so easy to store Fuel D • easy to light, but harder than A or B • little bit of smoke • gives off most heat • liquid so easy to store Conclusion (any justified) • e.g. B best as although less energy than D easier to ignite and little smoke • e.g. D best although smokier gives more energy (6) No rewardable content • a limited explanation e.g. D gives off most heat • the answer communicates ideas using simple language and uses limited scientific terminology • spelling, punctuation and grammar are used with limited accuracy • a simple explanation with correct comparative statement about at least three properties and two fuels, e.g. D gives off most heat and gives a little smoke but A is easier/very easy to light OR conclusion with statement about two properties and one fuel e.g. B is best because it is very easy to light, and gives no smoke • the answer communicates ideas showing some evidence of clarity and organisation and uses scientific terminology appropriately
3
5-6
• spelling, punctuation and grammar are used with some accuracy • a detailed explanation with correct comparative statement about three properties and three fuels e.g. A and B are the easiest to light and give off no smoke but give lowest temperature rise and D gives the most heat OR a conclusion with statement about three properties e.g. D is the best fuel because it is quite easy to light and produces biggest temperature rise even though gives off (little) smoke • the answer communicates ideas clearly and coherently uses a range of scientific terminology accurately • spelling, punctuation and grammar are used with few errors
Q55. Answer (a)(i)
Acceptable answers
A (ethene can form a polymer)
(a)(ii)
Allow methyl group
Mark (1) (3)
• propane [exact spelling](1) • C3H8 (1)
(a)(iii)
(1) description including the following points • (add) bromine (water) (1) • (orange to) colourless (1)
(2) allow decolourised / ignore discoloured, clear
Indicative Content QWC
*(b)
A description including some of the following points recycling – advantages saves raw materials/crude oil / saves making more plastic landfill sites do not fill up as plastics nonbiodegradable less possible damage to animals from discarded waste less energy used (in recycling than in starting from crude oil) recycling – disadvantages transport to collection area/recycling point uses fuel collection point may
Mark
(6)
Level 1
0 1-2
cause litter problem/eyesore etc plastics need to be sorted burning – advantages and disadvantages volume / amount of waste (bags) decreased energy released can be used landfill sites do not fill up as plastics nonbiodegradable burning could produce toxic/poisonous fumes /harmful gases burning produces carbon dioxide any general comments about reducing pollution, less harm to the environment and economic issues etc can be ignored. No rewardable content • a limited description e.g. recycling is good as plastics do not rot • the answer communicates ideas using simple language and uses limited scientific terminology • spelling, punctuation and grammar are used with limited accuracy
2
3-4 • a simple description e.g. plastic bags do not rot so burning is good because it leaves little waste • the answer communicates ideas showing some evidence of clarity and organisation and uses scientific terminology appropriately • spelling, punctuation and grammar are used with some accuracy
3
5-6 • a detailed description e.g. recycling is good because it conserves oil but the plastics do have to be sorted first • the answer communicates ideas clearly and coherently uses a range of
scientific terminology accurately • spelling, punctuation and grammar are used with few errors
Q56. Question Number (i) Question Number (ii) Question Number (iii)
Answer
Acceptable answers
Mark
alkene(s) Answer
Acceptable answers
(1) Mark
C16H34 Answer
Acceptable answers
(1) Mark
allow 1 mark for incorrect structure, but containing only two carbons and with double bond
(2)
Q57. Answer (i)
Acceptable answers
A (ethene can form a polymer)
(ii)
Allow methyl group
Mark (1) (3)
• propane [exact spelling](1) • C3H8 (1)
(iii)
(1) description including the following points • (add) bromine (water) (1) • (orange to) colourless (1)
(2) allow decolourised / ignore discoloured, clear
Q58. Question Number (i) Question Number (ii)
Answer
Acceptable answers
Mark
B Answer
Acceptable answers
(1) Mark
A description including the following points
(2)
• renewable (1) • (therefore) supplies will not be exhausted (1) OR• growing plants takes in carbon dioxide (1) • (therefore) little change in carbon dioxide in atmosphere (1)
Q59. Indicative Content QWC
Level 1
*
0 1-2
Mark
advantages (6) • renewable / sustainable • more plants can be grown • crops use up carbon dioxide and produce oxygen when growing /photosynthesising • carbon neutral because the carbon produced during combustion is used when growing the plants • does not use up crude oil/nonrenewable resourcesdisadvanta ges • crops grown for bio-fuels use up land • land could otherwise be used to provide homes / less farmland available for growing food crops • lots of crops required to provide a small amount of biomethane • bad season reduces availability • carbon emissions due to transport and production if qualified No rewardable content • a limited description e.g. using biomethane conserves fossil fuels and uses up carbon dioxide when plants are grown • the answer communicates ideas using simple language and uses limited scientific terminology • spelling, punctuation and grammar
are used with limited accuracy 2
3-4 • a simple description e.g. growing plants to produce biomethane is sustainable and conserves fossil fuels but uses up lots of farm land which could be used to grow plants for food • the answer communicates ideas showing some evidence of clarity and organisation and uses scientific terminology appropriately • spelling, punctuation and grammar are used with some accuracy
3
5-6 • detailed description e.g growing plants remove carbon dioxide from the air during photosynthesis and conserves fossil fuels but lots of crops are required to make biomethane and this uses up farm land which could otherwise be used to grow crops for food • the answer communicates ideas clearly and coherently uses a range of scientific terminology accurately • spelling, punctuation and grammar are used with few errors
Q60. Question Number (i) Question Number (ii)
Answer
Acceptable answers
Mark
C Answer
Acceptable answers
(1) Mark
B
(1)
Q61. Question Number (a) Question Number (b)
Question Number (c)(i)
Question Number (c)(ii)
Question Number QWC
Answer
Acceptable answers
Mark
D Answer
Acceptable answers
(1) Mark
An explanation linking the following • carbon dioxide / water vapour (released into the atmosphere) (1) • absorbs OWTTE heat (radiated from Earth)(1) Answer
Ignore reference to greenhouse gases or global warming Mention of ozone layer forbids award of second point
Acceptable answers
(2) Mark
(biofuels) renewable / plants remove carbon dioxide from atmosphere / conserves fossil fuels Answer
(almost) carbon neutral ignore biofuels don’t run out the word sustainable must be explained to score Acceptable answers
(1) Mark
an explanation linking the following • (growing crops for biofuels) requires land (1) • less land for food production / less food / deforestation / destroys habitat / food prices increase (1)
ignore cost of biofuels v fossil fuels note biofuels are crops so food crops must be specified
*(d)
Indicative Content
(2) Mark
an explanation linking some of the following: Production• lack of / insufficient oxygen • blocked burner jets / poor servicing leads to lack of oxygen • poor ventilation leads to lack of oxygen • complete combustion cannot take place Product• produces
(6)
Level 1
0 1-2
2
3-4
3
5-6
carbon / soot • produces carbon monoxide Effects• wastes fuel • soot stains / damages decorations etc • soot causes health problems • soot may block gas jets • carbon monoxide is toxic • combines with haemoglobin / forms carboxyhaemoglobin • prevents blood carrying oxygen • no oxygen reaches cells / no respiration / death No rewardable content • a limited explanation e.g. in limited air carbon monoxide forms • the answer communicates ideas using simple language and uses limited scientific terminology • spelling, puncuation and grammar are used with limited accuracy • a simple explanation e.g. ‘incomplete combustion of methane is caused by lack of oxygen and forms carbon monoxide which is a toxic gas’ • the answer communicates ideas showing some evidence of clarity and organisation and uses scientific terminology appropriately • spelling, punctuation and grammar are used with some accuracy • a detailed explanation e.g. ‘if a room is poorly ventilated, the heater will have a limited supply of air causing incomplete combustion. Carbon monoxide gas is formed. Carbon monoxide combines with haemoglobin and is therefore toxic’ • the answer communicates ideas clearly and coherently uses a range of scientific terminology accurately • spelling, punctuation and grammar are used with few errors
Q62. Answer
Acceptable answers
(i)
(ii)
Mark (2)
• 2CH4 + 3 O2 (1) • 2CO + 4 H2O (1) An description linking • (carbon monoxide) combines with haemoglobin/red blood cells (1) • lack of oxygen (to brain/cells) (1)
forms carboxyhaemoglobin reacts with/joins (on to) haemoglobin so less/no oxygen can be carried carbon monoxide replaces oxygen Ignore suffocation
(2)
Q63. Question Number (i)
Answer
Acceptable answers
Mark
• carbon (1) • hydrogen (1)
Question Number (ii)
Answer
in either order ignore symbols look for key words but reject carbon dioxide Acceptable answers
(2) Mark
(turns) colourless/decolouris es/ (orange) colour disappears
loses its colour ignore clear/transparent (1)
Q64. Question Number (i)
Question Number (ii)
Question Number (iii)
Answer
Acceptable answers
An explanation linking two of the following points • break down of (hydrocarbons/molec ules / alkanes) (1) • into smaller (hydrocarbons/molec ules / alkanes) (1) Answer
Ignore ‘chains of …..’/ polymers Ignore ‘separating Ignore reasons for cracking
an explanation linking the following • (molecule) containing (carboncarbon) double / multiple bond (1) • contains (atoms of) carbon and hydrogen (1) • only (1) Answer
Allow references to addition reactions. Ignore ‘alkene’, ‘spare bonds’, ‘doesn’t have max no of atoms or H bonded’ Can only score third point if second point scored
a description including the following • from orange/brown/yellow (1) • to colourless (1)
Allow red-brown but no other mention of red Ignore clear / discolour
Question Number (a)
Answer
Acceptable answers
(b)(i)
Acceptable answers
Answer
Mark (1)
Acceptable answers
C16H34 Question Number
Mark
Acceptable answers
alkene(s)
(b)(ii)
(3) Mark
(1) Answer
Question Number
(2) Mark
(2)
A Question Number
(b)(iii)
Acceptable answers
Mark
Mark (1)
Answer
Acceptable answers allow 1 mark for incorrect structure, but containing only two carbons and with double bond
Mark
(2)
Question Number (c)
Answer
Acceptable answers
An explanation linking three of the following points • surplus of larger molecules (diesel oil, fuel oil, bitumen (1) • shortage of petrol / gases (1) • shorter chain molecules more useful (1)
alkenes formed (1) (alkenes can be used) to make polymers (1) Accept any other correct deduction from table
Answer
Acceptable answers other words which make sequence clear use of (Bunsen) valve
(a)
remove delivery tube from water before stopping heating
(b) (c)
B C 4H 8 contains a double/multiple bond
(d)
A description to include • bromine water is orange (1) • propane: (remains) orange / no colour change (1) • propene: becomes colourless /decolourises (1) An explanation linking any two of • shorter chain molecules are more useful ORA (1) • demand for shorter chain molecules ORA (1) • meets demand • reduces the excess of longer chain molecules (1) • (cracking) produces alkenes (1) • alkenes used to make polymers (1)
(e)
Mark
(3)
ignore "spare bonds" ignore reference to number of hydrogen atoms attached. red / yellow / brown any combination of these ignore clear /discolours
reject long chain molecules are useless named fraction/use/fuel n amed fraction /use/fuel
Mark (1)
(1) (1)
(3)
(2)
Answer (a)(i) (a)(ii) (a)(iii) (b) (c)(i)
(c)(ii)
fuel oil gases diesel oil C hydrogen • 2CH4 + 3 O2 (1) • 2CO + 4 H2O (1) An description linking • (carbon monoxide) combines with haemoglobin/red blood cells (1) • lack of oxygen (to brain/cells) (1)
(d)
An explanation linking two of • uses up (farm)land/space/are a (to grow crops for fuel) (1) M1 • less (farm)land to grow crops for food (1) M2 • can cause food prices to rise (1) M3 • (could lead to) food shortages/famine/sta rvatio n/ poverty (1) M4 • (could lead to) deforestation/soil erosion (1) M5
Question
Answer
Acceptable answers gas diesel
forms carboxyhaemoglobin reacts with/joins (on to) haemoglobin so less/no oxygen can be carried carbon monoxide replaces oxygen Ignore suffocation less food produced/grown I gnore reference to habitats Ignore decrease in biodiversity Ignore reference to carbon dioxide levels/greenhouse effect
Acceptable answers
Mark (1) (1) (1) (1) (2)
(2)
(2)
Mark
Number
1 mark each
(3)
Question Number
Answer
Acceptable answers
Mark
(a)
fractional distillation (2) Question Number
(b)
Answer
(c)
Answer
(d)
Acceptable answers
Acceptable answers
C
(e)
An explanation including the following: • (compound of) carbon and hydrogen (1) • only (1)
(f)
Answer A description including the following • (pass gas into) limewater / calcium hydroxide solution which turns milky / cloudy / white precipitate (2)
Question Number (i)
Answer
Acceptable answers
(ii)
(2) Acceptable answers Allow limewater / calcium hydroxide solution with incorrect or no observation (1) Ignore puts out a flame
Mark
(2)
Acceptable answers
Mark (1)
Answer all oxygen reacted / used up / excess copper (present)
Question Number
Mark
Ignore reference to mixture
C Question Number
Mark (1)
Answer
Question Number
Mark (1)
Answer
Question Number
Mark (1)
fuel oil Question Number
(2)
Acceptable answers
(oil well) C Question Number
(iii)
distillation / fractionation (1)
Answer volume gas used = 32-24 (1) = 8 (cm3) percentage = 3224/32 × 100 (1) =
Acceptable answers no oxygen left / insufficient oxygen Reject not enough time / not hot enough
Mark
(1)
Acceptable answers
Mark
(2)
25 (%) Question Number (iv)
Answer oxygen in air in test tube also reacted /more than 32 cm3 of air because of air in test tube / air in test tube will react but is not measure
Question Number (a)
sulfur
Question Number (b)
Question Number (c)
Answer
Acceptable answers some gases leaked out of apparatus allow another gas has reacted with copper (1)
Acceptable answers allow S allow recognisable spelling not sulfate not sulfide not sulfite
Answer
Acceptable answers
any two of the following • damages one of statues / buildings / stonework /limestone/marble/ch alk/ iron / steel (1) • damages one of trees/plants/soil (1) • specified water life affected e.g. fish die (1)
erodes/corrodes/we athers/ decays/ruins/rots/dis solves/ destroys/affects ignore any other rocks ignore deforestation makes lakes acidic
Answer
Acceptable answers
an explanation linking • carbon dioxide has increased (1) with one of the following points • (average) temperature has increased /as well/also/too (so there may be a link) (1) OR • although (average) temperature change it might be a natural fluctuation (1) OR • although (average) temperature change
Mark
Mark
(1) Mark
(2) Mark
(2)
is not necessarily caused by carbon dioxide levels (1) Question Number (d)
QWC
Answer
Acceptable answers
A Question Number *e
Level 1
0 1-2
2
3-4
Mark (1)
Indicative Content
Mark
An explanation linking some of the following points Fuel A • very easy to light • not smoky • gives off least heat • gas so harder to store Fuel B • very easy to light • not smoky • doesn’t give off most heat • liquid so easy to store Fuel C • easy to light, but harder than A or B • little bit of smoke • doesn’t give off most heat • liquid so easy to store Fuel D • easy to light, but harder than A or B • little bit of smoke • gives off most heat • liquid so easy to store Conclusion (any justified) • e.g. B best as although less energy than D easier to ignite and little smoke • e.g. D best although smokier gives more energy (6) No rewardable content • a limited explanation e.g. D gives off most heat • the answer communicates ideas using simple language and uses limited scientific terminology • spelling, punctuation and grammar are used with limited accuracy • a simple explanation with correct comparative statement about at least three properties and two fuels, e.g. D gives off most heat and gives a little smoke but A is easier/very easy to light OR conclusion with statement about two properties and one fuel
3
5-6
Question Number (a)(i)
Answer
Acceptable answers
• carbon • hydrogen • sulfur allow any one correct for 1 mark Question Number
(a)(ii)
Answer
(b)(i)
Answer
Acceptable answers
Answer A description linking two of the following points • (black deposit is) carbon / soot (1) • (formed by) incomplete
Mark (1)
Acceptable answers
• C5H12 + 8O2 → 5CO2 + 6H2O • LHS formulae correct (1) • RHS formulae correct (1) • balancing correct formulae (1) Question Number
Mark
(2)
acid rain / specific effect of acid rain Question Number
(b)(ii)
e.g. B is best because it is very easy to light, and gives no smoke • the answer communicates ideas showing some evidence of clarity and organisation and uses scientific terminology appropriately • spelling, punctuation and grammar are used with some accuracy • a detailed explanation with correct comparative statement about three properties and three fuels e.g. A and B are the easiest to light and give off no smoke but give lowest temperature rise and D gives the most heat OR a conclusion with statement about three properties e.g. D is the best fuel because it is quite easy to light and produces biggest temperature rise even though gives off (little) smoke • the answer communicates ideas clearly and coherently uses a range of scientific terminology accurately • spelling, punctuation and grammar are used with few errors
Mark
(3) Acceptable answers
Mark
(2)
combustion (1) • (formed because) insufficient / limited oxygen (1) Question Number (b)(iii)
Answer
Acceptable answers
Any three from the following points • dodecane biggest temperature rise / pentane smallest rise (1) • dodecane used faster / pentane used slower (1) • dodecane gives out most heat / pentane gives out least (1) • comparison of temperature rise per gram for three fuels / gram of fuel used per ºC (1)
Answer (a) (b) (c)(i)
(c)(ii)
(c)(iii)
C hydrocarbons D power station furnaces CH4 + 2O2 → CO2 + 2H2O correct formulae on left CH4 + O2 (1) correct formulae on right CO2 + H2O (1) balancing of correct formulae(1) 48 (kJ) (1) or 5472 /114 = 48 (kJ) (1) or 5472/114 (1) Any two of easy to ignite / low boiling point / low viscosity (1) burns readily/easily / (in)flammable(1) not produce too much soot/ash/ smoke /
Mark
(3)
Acceptable answers
Mark (1)
Allow multiples or halves Allow = for → Reject obvious incorrect symbols and subscripts once only
(1) (3)
(1)
Ignore burns for a long time Ignore just 'releases a lot of energy' Ignore references to cost Ignore vague answers eg doesn't cause
(2)
(a)
(b) (c) (d)
burns with clean/blue flame / burns cleanly (1) easy to store/contain (1) easy to transport/transfer (1) high energy output per unit mass /volume (1) does not produce toxic gases/carbon dioxide/sulfur dioxide/greenhouse gases / contains a low amount of sulfur (1) fuel is readily available/easy to obtain/will not run out/long lasting/renewable (1) carbon neutral (1)
pollution/harmful gases Ignore answers written in the form of questions or statements that do not show a characteristic of a good fuel eg how easy is it to ignite the fuel? how much energy it produces Allow a little produces a lot of energy Allow produces a lot of miles/km per gallon/litre
Answer
Acceptable answers Ignore C, H Do not allow mixture of carbon and hydrogen 2nd mark dependant on 1st
An explanation linking the following • (compound of) carbon and hydrogen (1) • only (1) C heat energy fractional distillation 3 correct – 2 marks 1 or 2 correct – 1 mark
Mark
(2) (1) (1)
(2)
QWC
*(e)
Indicative Content An explanation including some of the following water • causes condensation • damp walls etc • damages
Mark
(6)
Level 1
0 1-2
decoration • greenhouse gas/ keeps in heatcarbon dioxide • greenhouse gas/ keeps in heat • may contribute to global warming • consequence s of global warming eg flooding/ drought / crop failure / disease/ melting ice caps / climate change etccarbon • soot • makes things dirty/ black • damages decoration • flues or jets could be blocked • can cause breathing problems • can cause firescarbon monoxide • toxic (ignore harmful etc) • (also) odourless and colourless • "silent killer" • (therefore) difficult to detect • combines with haemoglobin • in red blood cells • prevents oxygen being circulatedIn general references to pollution, environment etc are ignored No rewardable content • a limited description (about one product) e.g. carbon monoxide is toxic because it joins to blood
• the answer communicates ideas using simple language and uses limited scientific terminology • spelling, punctuation and grammar are used with limited accuracy 2
3-4 • a simple description (developed description of one product) eg carbon dioxide absorbs sun's heat and causes global warming which means ice caps melt or (limited description of two) e.g. carbon monoxide combines with haemoglobin so is toxic and carbon dioxide is a greenhouse gas causing global warming. • the answer communicates ideas showing some evidence of clarity and organisation and uses scientific terminology appropriately • spelling, punctuation and grammar are used with some accuracy
3
5-6 • a detailed description (developed description of one and limited description of one) or (limited description of three or more) e.g. toxic carbon monoxide cannot be detected and prevents the blood from carrying oxygen so is toxic: carbon dioxide is a greenhouse gas which causes global warming. • the answer communicates ideas clearly and coherently uses a range of scientific terminology accurately • spelling, punctuation and grammar are used with few errors