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Section A (multiple choice) Question Number 1 (a) Question Number 1 (b) Question Number 2 Question Number 3 Question Number 4 (a) Question Number 4(b) Question Number 4 (c) Question Number 4 (d) Question Number 5 Question Number 6 Question Number 7 Question Number 8 Question Number 9 Correct Answer B Correct Answer D Correct Answer D Correct Answer A Correct Answer B Correct Answer D Correct Answer C Correct Answer A Correct Answer B Correct Answer A Correct Answer C Correct Answer D Correct Answer C Mark 1 Mark 1 Mark 1 Mark 1 Mark 1 Mark 1 Mark 1 Mark 1 Mark 1 Mark 1 Mark 1 Mark 1 Mark 1
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Question Number 10 Question Number 11 Question Number 12 Question Number 13 Question Number 14 (a) Question Number 14 (b) Question Number 14 (c)
Correct Answer C Correct Answer D Correct Answer B Correct Answer D Correct Answer B Correct Answer A Correct Answer C
Mark 1 Mark 1 Mark 1 Mark 1 Mark 1 Mark 1 Mark 1
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Section B Question Number 15 (a)(i) Acceptable Answers Reject Mark 2
electrons (1) charge (1) square brackets not essential Mark independently Ignore (labelling of) nucleus unless incorrect Question Number 15 (a)(ii) Acceptable Answers 1s22s22p63s23p6 Allow electron number as sub script Allow orbitals as capital letters Allow TE from (a) (i) if Ca atom or Ca+ ion Question Number 15 (a)(iii) Acceptable Answers Smaller Because it has one less (sub) shell of electrons / orbital / energy level / less shielding (1) And the ratio of protons : electrons has increased / more protons than electrons / greater net force on remaining electrons (so remainder of electrons held more closely) / greater effective nuclear charge (1) Reject Mark 2 bigger scores zero greater nuclear charge /positive charge Reject Mark 1
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Question Number 15 (a)(iv)
Acceptable Answers Any two from: Strong (electrostatic) forces / attractions / bonds (between ions) (1) (ions) held in giant lattice / many (ionic) attractions / forces / bonds (1) So large amount of energy needed (to break apart ions) (1)
Reject
Mark 2
Any mention of covalent or metallic bonds or atoms or molecules scores zero High temperature Reject Electrons / particles are free to move Reject Atoms are different sizes Mark 1
Question Number 15 (b)(i)
Acceptable Answers Because the ions are free to move (when a potential difference is applied)
Question Number 15 (b)(ii)
Acceptable Answers The cations / barium and calcium (ions) are different sizes Ignore any discussion of reasons (could select either the calcium ion because it has more water molecules associated with it OR the barium ion because it has more shells of electrons and so larger)
Mark 1
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Question Number 15 (b)(iii)
Acceptable Answers Mass of calcium ions in 1 kg = 0.100 x 40 (= 4.0) (g) (1) If mass quoted must be correct to score first mark Hence 4.0 g per 1000 g of solution So ppm = (4.0/1000) x 1000000 = 4000 (ppm) (1) OR Mass of calcium ions in 1 kg = 0.100 x 40.1 (= 4.01) (g) (1) Hence 4.01 g per 1000 g of solution So ppm = (4.01/1000) x 1000000 = 4010 (ppm) (1) Correct answer alone = 2 marks Allow TE for second mark from incorrect mass
Reject
Mark 2
Question Number 15 (c)
Acceptable Answers (Sulfur / nitrogen oxides) form when (fossil) fuels are burnt / when petrol or diesel burn in vehicle engines / emissions from vehicle (engines) / volcanoes / lightning (1) They (react with water to) form sulfuric / sulfurous acid /nitric acid /acid rain / gases are acidic (1) Which reacts with limestone (to form soluble compounds) / limestone and acid take part in neutralisation / dissolves building / corrodes building (1) Allow correct equation for third mark but Ignore equations if mark already awarded. Ignore comments regarding erosion
Reject from factories alone
Mark 3
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Question Number 15 (d)
Acceptable Answers Either Yes, as the values match closely (so little deviation from ionic model) Or no, as the values are (slightly) different so a degree of covalency / not fully ionic
Reject
Mark 1
100% ionic covalent
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Question Number 16 (a)
Acceptable Answers Atoms (of an element) with the same number of protons (1) But with different number of neutrons (1) Same atomic number but different mass number only = (1) Element(s) with same number of protons but different number of neutrons = (1) max Ignore comments on electrons unless incorrect in which case award max 1
Reject
Mark 2
Question Number 16 (b)(i) Question Number 16 (b) (ii)
Acceptable Answers (Electric field) accelerates ions Acceptable Answers (Magnetic field) deflects / changes direction of / bends the beam of ions if the term ‘ions’ is missing or an incorrect term is used e.g. ‘atoms’, penalise only once in parts b (i) and b (ii)
Reject
Mark 1
Reject just bends ions
Mark 1
Question Number 16 (c)
Acceptable Answers % abundance = (135 x 9.01 + 136 x 10.81 + 137 x 12.32 + 138 x 67.86) /100 (1) = 137.4 (1) ignore units Allow TE for one slip in transfer of data from question Correct answer scores (2)
Reject
Mark 2
Just 137 as final answer 137.39 137.3903 137.390
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Question Number 16 (d)
Acceptable Answers three peaks (caused by Br2+ ions) (1) because ions (79Br-79Br)(+) and (81Br-79Br)(+) / (79Br-81Br)(+) and (81Br-81Br)(+) (1) Mark independently
Reject
Mark 2
Question Number 16 (e)
Acceptable Answers Any one analysis of material from space / drug testing in sport / identify breakdown products from drugs in body / quality control in pharmaceutical industry / identify molecules from sample with potential biological activity / radioactive dating with context e.g determine age of fossils / human remains The uses above must have a context / determining Mr of a molecule / evidence for structure from fragmentation pattern
Reject
Mark 1
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Question Number 17 (a)
Acceptable Answers
Reject
Mark 2
(1) for around carbon and its hydrogens (1) for around oxygen and its hydrogen Allow all dots or all crosses Ignore circles around atoms Question Number 17 (b)(i) Acceptable Answers C(s) / (graphite) + 2H2(g) + 2O2(g) Correct species (1) Allow oxygen above arrows rather than in box Balancing and state symbols (1) Second mark dependent on correct species except as below with either hydrogen or oxygen or both as atoms e.g C(s) / (graphite) + 4H(g) + 4O(g) Scores second mark Question Number 17 (b)(ii) Acceptable Answers Enthalpy / energy / heat(energy) change when one mole of a substance (1) Is formed from its elements (in their most stable / standard states) (1) Under standard conditions of 298K/ 25 ºC / any stated temperature AND 1 atm pressure / 101 kPa / 100 kPa (1) Definitions based on lattice enthalpies may score third mark only Reject heat required / heat given out / heat taken in Mark 3 Reject Mark 2
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Question Number 17 (b)(iii)
Acceptable Answers
Reject
Mark 2
∆HƟc = -∆H1Ɵ + ∆H2Ɵ (1)
=
(2 x −285.8 + −393.5) − (−239.1) = −726 (1) Ignore units Correct answer alone = 2 marks +726 = 1 -440.2 = 1 if omit multiply by 2
Question Number 17 (c)(i)
Acceptable Answers 20.7 x 200 x 4.18 = 17305(.2) (J) ignore sf except 1 sf i.e. 20000 OR 20.7 x 200 x 0.00418 = 17.305(2) kJ ignore sf except 1 sf i.e. 20 ignore signs ignore mol−1
Reject
Mark 1
Question Number 17 (c) (ii)
Acceptable Answers 0.848/32 = 0.0265 (mol) ignore sf except 1 sf i.e. 0.03
Reject
Mark 1
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Question Number 17 (c)(iii)
Acceptable Answers 17305.2/0.0265 = −653000 (J mol−1 ) (3sf) OR −653 (kJ mol−1) (3sf) Ignore missing units but penalise incorrect units Allow TE from (c)(i) & (ii)
Reject
Mark 1
Question Number 17 (c)(iv)
Acceptable Answers Any two from As heat/energy absorbed by apparatus / heat/energy ‘lost’ to surroundings (1) methanol not completely burnt / incomplete combustion (1) methanol ‘lost’ by evaporation (1) cannot ensure all products are at standard conditions at end of reaction / water is produced as a gas / reaction not carried out in the standard conditions (1)
Reject
Mark 2
just heat/energy loss just incomplete reaction
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Question Number 18 (a)(i)
Acceptable Answers Crude oil / petroleum / coal
Reject Oil on its own / Natural gas / fossil fuels / any named fraction of crude oil Reject
Mark 1
Question Number 18 (a)(ii)
Acceptable Answers use of high temperatures / heat (in the absence of air) / thermal decomposition / catalysts (1) Either to break large molecules / to form smaller molecules / to break bonds in large molecules / to break carbon-carbon bonds (1) OR producing alkenes / producing carbon-carbon double bonds (1)
Mark 2
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Question Number 18 (a)(iii)
Acceptable Answers Risks (2) Amendments (2) Risk exposure to harmful / toxic fumes Escape of flammable / harmful / toxic reactants or products from ill fitting bung Escape of flammable / harmful /toxic reactants or products from poorly positioned delivery tube suck back Amendment Set up in fume cupboard Correct fitting of bung
Reject
Mark 4
Dangerous
Placement of delivery tube below mouth of test tube / use a longer delivery tube Attach Bunsen valve / remove delivery tube from water before stopping heating etc
collect in syringe
Mark all 4 points independently If escaping gases linked to 2 amendments but no risk mentioned then allow 1 for risk Question Number 18 (b)(i) Acceptable Answers Reagent – Hydrogen/H2 (1) Catalyst – Nickel/Ni/palladium/Pd/platinum/Pt (1) Mark independently Question Number 18 (b)(ii) Acceptable Answers 1,2 – dibromoethane (1) ignore punctuation Reject 1,2 - bromoethane dibromoethane Mark 2 Reject Mark 2
H H H C C H Br Br
(1) C2H4Br2 Skeletal formula
Mark independently Allow CH2BrCH2Br
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Question Number 18 (b)(iii) Question Number 18 (c)(i)
Acceptable Answers
Reject clear Reject
Mark 1 Mark 3
From purple / pink → colourless Acceptable Answers
arrow from bromide ion can start from any part of the bromide ion and can go towards the C or the + sign on the intermediate bromide ion must show negative charge ∂- on bromide ion for third mark
allow 2 max for addition of Br2 and any other electrophilic additions half headed arrows used throughout penalise only once Question Number 18 (c)(ii) Acceptable Answers Bromine / bromide / hydrogen could add to either carbon (in the double bond) / bromide / bromine could add to either primary or secondary carbocation / (propene is unsymmetrical) so could form 1-bromopropane and / or 2-bromopropane. Allow correct structural or displayed formulae. Reject bromine could add to any of the three carbons Mark 1
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Question Number 18 (d)
Acceptable Answers
Reject
Mark 2
H C H
C6H5 H C H C H
C6H5 C H
position of hydrogen atoms and phenyl groups (1) Allow phenyl groups on 2nd and 3rd carbon OR 1st and 4th OR 1st and 3rd carbon carbon single bonds and continuation bonds (1) second mark not awarded for incorrect monomer
(1) max with or without square brackets and n or numbers Do not penalise H from phenyl groups attaching to carbon chains Ignore extra square brackets, numbers and ‘n’ provided 2 monomer units shown
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Question Number 18 (e)(i)
Acceptable Answers Any two (raw material for) paper cup requires cutting down trees (1) polystyrene cup uses less energy (280 kWh rather than 980 kWh) to produce so less CO2 released / less fossil fuels (1) polystyrene cup releases less sulfur based compounds into air so less chance of forming acid rain / less chance of damaging buildings / acidifying lakes (produces 3.5 kg rather than 11 kg) (1) polystyrene cup releases no chlorine compounds which damages ozone layer / poisonous (produce 0 kg rather than 0.4 kg) (1) 2 pieces of data chosen with no explanation allow 1 mark Ignore comments regarding water
Reject
Mark 2
Question Number 18 (e)(ii)
Acceptable Answers 2 additional factors e.g ease of recyclability whether cup is easy to reuse space taken up in landfill type and amount of gases formed if incinerated useful heat obtained if incinerated biodegradeability / how long they take to decompose management of gases produced during decomposition durability / how long the cup lasts method of disposal Ignore comments regarding atom economy Ignore comments regarding acid rain / ozone layer / greenhouse gases unless linked to gases produced during disposal
Reject
Mark 2
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