Cambridge IGCSE Chemistry (9-1) 0971 — 2024 May/June Paper 4 · Variant 1

*0876265829* CHEMISTRY 0971/41 Paper 4 Theory (Extended) May/June 2024  1 hour 15 minutes You must answer on the question paper. No additional materials are needed. INSTRUCTIONS ● Answer all questions. ● Use a black or dark blue pen. You may use an HB pencil for any diagrams or graphs. ● Write your name, centre number and candidate number in the boxes at the top of the page. ● Write your answer to each question in the space provided. ● Do not use an erasable pen or correction fluid. ● Do not write on any bar codes. ● You may use a calculator. ● You should show all your working and use appropriate units. INFORMATION ● The total mark for this paper is 80. ● The number of marks for each question or part question is shown in brackets [ ]. ● The Periodic Table is printed in the question paper. IB24 06_0971_41/FP © UCLES 2024 [Turn over This document has 16 pages. Any blank pages are indicated. Cambridge IGCSE™(9–1)

2 0971/41/M/J/24 © UCLES 2024 1 Name the process that is used to: (a) convert sulfur dioxide into sulfur trioxide in the manufacture of sulfuric acid … [1] (b) obtain water from aqueous sodium chloride … [1] (c) extract aluminium from purified bauxite … [1] (d) separate petroleum into useful substances … [1] (e) produce ethanol from aqueous glucose … [1] (f) manufacture alkenes and hydrogen from large alkane molecules … [1] (g) separate a mixture of soluble coloured substances. … [1]  [Total: 7]

3 0971/41/M/J/24 © UCLES 2024 [Turn over 2 Complete Table 2.1. Table 2.1 atom or ion number of protons number of electrons number of neutrons 37Cl 17 17 63Cu+ 29 34 16 18 17  [5]

4 0971/41/M/J/24 © UCLES 2024 3 This question is about the elements sodium and fluorine and the compound sodium fluoride. (a) Sodium reacts with fluorine to form sodium fluoride. Write a symbol equation for this reaction. … [2] (b) Some properties of sodium, fluorine and sodium fluoride are shown in Table 3.1. Table 3.1 melting point / °C boiling point / °C conduction of electricity when solid conduction of electricity in aqueous solution sodium 98 883 good fluorine –220 –188 poor sodium fluoride 993 1695 poor good (i) Explain why sodium conducts electricity when it is a solid. … [1] (ii) Complete the dot-and-cross diagram in Fig. 3.1 of a molecule of fluorine. Show outer shell electrons only. F F Fig. 3.1  [2] (iii) Deduce the physical state of fluorine at –200 °C. Use the data in Table 3.1 to explain your answer. physical state … explanation … …  [2]

5 0971/41/M/J/24 © UCLES 2024 [Turn over (iv) Explain in terms of structure and bonding why sodium fluoride has a much higher melting point than fluorine. … … … … … [3] (c) Dilute aqueous sodium fluoride undergoes electrolysis. Hydrogen is produced at the cathode. (i) State what is meant by the term electrolysis. … … … [2] (ii) Write an ionic half-equation for the production of hydrogen at the cathode. … [2]  [Total: 14]

6 0971/41/M/J/24 © UCLES 2024 4 Hydrogen iodide thermally decomposes into iodine and hydrogen. The reaction is reversible. 2HI(g) I2(g) + H2(g) colourless gas purple gas colourless gas Fig. 4.1 shows a gas syringe containing a mixture of hydrogen iodide, iodine and hydrogen gases. The gas syringe is sealed and the mixture is heated to 300 °C. The mixture of gases reaches equilibrium and is purple. end sealed plunger equilibrium mixture of hydrogen iodide, iodine and hydrogen Fig. 4.1 (a) State what is meant by the term equilibrium. … … … [2] (b) The pressure of the mixture is increased. All other conditions stay the same. The position of equilibrium does not change. The colour of the gaseous mixture turns darker purple. The temperature remains constant. 2HI(g) I2(g) + H2(g) colourless gas purple gas colourless gas (i) Explain why the position of equilibrium does not change. … … [1] (ii) Suggest why the colour of the mixture of gases turns darker purple. … … [1]

7 0971/41/M/J/24 © UCLES 2024 [Turn over (c) The temperature of the mixture of gases is decreased. All other conditions stay the same. The mixture of gases turns lighter purple. State what can be deduced about the forward reaction from this information. … [1] (d) Deduce the oxidation number of iodine, I, in: HI … I2. …  [2] (e) Methanol is manufactured by reacting carbon monoxide with hydrogen. CO(g) + 2H2(g) CH3OH(g) The rate of formation of methanol increases when a catalyst is used. (i) Choose from the list the element that is most likely to be used as the catalyst. Draw a circle around your chosen answer. calcium carbon copper sodium sulfur [1] (ii) State the effect on the position of equilibrium when a catalyst is used. … [1] (iii) State the effect that a catalyst has on the activation energy, Ea, of a reaction. … [1]  [Total: 10]

8 0971/41/M/J/24 © UCLES 2024 5 (a) Lead(II) bromide, PbBr2, is an insoluble salt and is made by precipitation. (i) Name two aqueous solutions that produce a precipitate of lead(II) bromide when they are mixed. 1 … 2 …  [2] (ii) Describe how to produce a pure sample of lead(II) bromide from the mixture of aqueous solutions in (a)(i). … … [2] (iii) Write an ionic equation for the precipitation reaction which produces lead(II) bromide. Include state symbols. … [3] (b) When iron(II) sulfate crystals are heated strongly, sulfur dioxide gas is given off. Describe a test for sulfur dioxide gas. test … observations …  [2] (c) Complete the equation for the thermal decomposition of hydrated cobalt(II) nitrate. 2Co(NO3)2•4H2O → …CoO + …NO2 + O2 + …H2O [2]

9 0971/41/M/J/24 © UCLES 2024 [Turn over (d) Hydrated cobalt(II) sulfate, CoSO4•xH2O, produces water when it is heated. CoSO4•xH2O(s) → CoSO4(s) + xH2O(g) A student does an experiment to determine the value of x in CoSO4•xH2O. step 1 The student weighs a sample of hydrated cobalt(II) sulfate. step 2 The student heats the sample of hydrated cobalt(II) sulfate. step 3 The student weighs the remaining solid after heating. (i) Describe what else the student should do to ensure that all the water has been given off. No other substances are required. … … … [2] (ii) In an experiment, 1.405 g of CoSO4•xH2O is heated until all the water is given off. The mass of CoSO4 that remains is 0.775 g. [Mr: CoSO4, 155; H2O, 18] Determine the value of x using the following steps. ● Calculate the number of moles of CoSO4 that remains.  … mol ● Calculate the mass of H2O given off.  … g ● Calculate the number of moles of H2O given off.  … mol ● Determine the value of x.  x = …  [4]  [Total: 17]

10 0971/41/M/J/24 © UCLES 2024 6 This question is about metals. (a) Fig. 6.1 shows a blast furnace used to extract iron from its ore. waste gases slag air air A Fig. 6.1 (i) Coke and iron ore are added at the top of the blast furnace. Name one other substance that is added at the top of the blast furnace. … [1] (ii) Name the substance that leaves the blast furnace at A. … [1] (iii) Slag is produced from an impurity in iron ore. Name the impurity in iron ore that is converted into slag. … [1] (iv) Name two substances that react together to produce the high temperature in the blast furnace. … and … [1] (v) Name two waste gases that leave the blast furnace. 1 … 2 …  [2]

11 0971/41/M/J/24 © UCLES 2024 [Turn over (b) Zinc is produced from zinc oxide in a furnace. The zinc is produced as a gas. It then forms molten zinc. (i) Suggest why the zinc produced inside the furnace is a gas. … [1] (ii) State the name of the physical change that occurs when gaseous zinc is converted into molten zinc. … [1] (c) Zinc is used to coat iron to prevent rusting. (i) Name the process used to coat iron with zinc as a method of rust prevention. … [1] (ii) When the zinc coating is scratched, the iron underneath does not rust. Explain why the iron underneath the zinc does not rust. … … [2] (d) Zinc oxide neutralises both acids and bases. (i) State the general name given to oxides that neutralise both acids and bases. … [1] (ii) When zinc oxide neutralises aqueous sodium hydroxide, sodium zincate is formed. The formula of the zincate ion is ZnO2 2–. Deduce the formula of sodium zincate. … [1] (iii) Name the zinc compound that forms when zinc oxide neutralises dilute sulfuric acid. … [1]  [Total: 14]

12 0971/41/M/J/24 © UCLES 2024 7 Many organic compounds contain carbon and hydrogen only. (a) (i) Organic compound A has the following composition by mass. C, 82.76%; H, 17.24% Calculate the empirical formula of compound A.  empirical formula = … [3] (ii) Compound B has the empirical formula CH2 and a relative molecular mass of 70. Determine the molecular formula of compound B.  molecular formula = … [1] (b) Fig. 7.1 shows a section of polymer Q. C CH3 CH3 H C H C CH3 CH3 H C H Fig. 7.1 ● Draw the displayed formula of the monomer that forms polymer Q. ● Name the monomer used to form polymer Q. …  [3]

13 0971/41/M/J/24 © UCLES 2024 [Turn over (c) Propene, C3H6, can be produced by heating C11H24. The products of the reaction are propene, hydrogen and one other product in a 1 : 1 : 1 mole ratio. Complete the symbol equation for this reaction. C11H24 → C3H6 + H2 + … [1] (d) Carboxylic acids and esters contain carbon, hydrogen and oxygen only. An ester X and a carboxylic acid Y both contain 3 carbon atoms. X and Y have the same molecular formula. (i) State the name given to compounds with the same molecular formula but different structural formulae. … [1] (ii) Esters are made by the reaction between carboxylic acids and alcohols. Ester X is methyl ethanoate. Name the carboxylic acid and the alcohol used to make methyl ethanoate. carboxylic acid … alcohol …  [2] (iii) Draw the displayed formula of carboxylic acid Y. Name the carboxylic acid. name …  [2]  [Total: 13]

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15 0971/41/M/J/24 © UCLES 2024 Permission to reproduce items where third-party owned material protected by copyright is included has been sought and cleared where possible. Every reasonable effort has been made by the publisher (UCLES) to trace copyright holders, but if any items requiring clearance have unwittingly been included, the publisher will be pleased to make amends at the earliest possible opportunity. To avoid the issue of disclosure of answer-related information to candidates, all copyright acknowledgements are reproduced online in the Cambridge Assessment International Education Copyright Acknowledgements Booklet. This is produced for each series of examinations and is freely available to download at www.cambridgeinternational.org after the live examination series. Cambridge Assessment International Education is part of Cambridge Assessment. Cambridge Assessment is the brand name of the University of Cambridge Local Examinations Syndicate (UCLES), which is a department of the University of Cambridge. BLANK PAGE

16 0971/41/M/J/24 © UCLES 2024 Group The Periodic Table of Elements 1 H hydrogen 1 2 He helium 4 I II III IV V VI VII VIII 3 Li lithium 7 4 Be beryllium 9 atomic number atomic symbol Key name relative atomic mass 11 Na sodium 23 12 Mg magnesium 24 19 K potassium 39 20 Ca calcium 40 37 Rb rubidium 85 38 Sr strontium 88 55 Cs caesium 133 56 Ba barium 137 87 Fr francium – 88 Ra radium – 5 B boron 11 13 Al aluminium 27 31 Ga gallium 70 49 In indium 115 81 Tl thallium 204 113 Nh nihonium – 6 C carbon 12 14 Si silicon 28 32 Ge germanium 73 50 Sn tin 119 82 Pb lead 207 22 Ti titanium 48 40 Zr zirconium 91 72 Hf hafnium 178 104 Rf rutherfordium – 23 V vanadium 51 41 Nb niobium 93 73 Ta tantalum 181 105 Db dubnium – 24 Cr chromium 52 42 Mo molybdenum 96 74 W tungsten 184 106 Sg seaborgium – 25 Mn manganese 55 43 Tc technetium – 75 Re rhenium 186 107 Bh bohrium – 26 Fe iron 56 44 Ru ruthenium 101 76 Os osmium 190 108 Hs hassium – 27 Co cobalt 59 45 Rh rhodium 103 77 Ir iridium 192 109 Mt meitnerium – 28 Ni nickel 59 46 Pd palladium 106 78 Pt platinum 195 110 Ds darmstadtium – 29 Cu copper 64 47 Ag silver 108 79 Au gold 197 111 Rg roentgenium – 30 Zn zinc 65 48 Cd cadmium 112 80 Hg mercury 201 112 Cn copernicium – 114 Fl flerovium – 116 Lv livermorium – 7 N nitrogen 14 15 P phosphorus 31 33 As arsenic 75 51 Sb antimony 122 83 Bi bismuth 209 115 Mc moscovium – 8 O oxygen 16 16 S sulfur 32 34 Se selenium 79 52 Te tellurium 128 84 Po polonium – 9 F fluorine 19 17 Cl chlorine 35.5 35 Br bromine 80 53 I iodine 127 85 At astatine – 117 Ts tennessine – 10 Ne neon 20 18 Ar argon 40 36 Kr krypton 84 54 Xe xenon 131 86 Rn radon – 118 Og oganesson – 21 Sc scandium 45 39 Y yttrium 89 57–71 lanthanoids 89–103 actinoids 57 La lanthanum 139 89 Ac lanthanoids actinoids The volume of one mole of any gas is 24 dm3 at room temperature and pressure (r.t.p.). actinium – 58 Ce cerium 140 90 Th thorium 232 59 Pr praseodymium 141 91 Pa protactinium 231 60 Nd neodymium 144 92 U uranium 238 61 Pm promethium – 93 Np neptunium – 62 Sm samarium 150 94 Pu plutonium – 63 Eu europium 152 95 Am americium – 64 Gd gadolinium 157 96 Cm curium – 65 Tb terbium 159 97 Bk berkelium – 66 Dy dysprosium 163 98 Cf californium – 67 Ho holmium 165 99 Es einsteinium – 68 Er erbium 167 100 Fm fermium – 69 Tm thulium 169 101 Md mendelevium – 70 Yb ytterbium 173 102 No nobelium – 71 Lu lutetium 175 103 Lr lawrencium –

This document consists of 11 printed pages. © Cambridge University Press & Assessment 2024 [Turn over Cambridge IGCSE™ (9–1) CHEMISTRY (9–1) 0971/41 Paper 4 Theory (Extended) May/June 2024 MARK SCHEME Maximum Mark: 80 Published This mark scheme is published as an aid to teachers and candidates, to indicate the requirements of the examination. It shows the basis on which Examiners were instructed to award marks. It does not indicate the details of the discussions that took place at an Examiners’ meeting before marking began, which would have considered the acceptability of alternative answers. Mark schemes should be read in conjunction with the question paper and the Principal Examiner Report for Teachers. Cambridge International will not enter into discussions about these mark schemes. Cambridge International is publishing the mark schemes for the May/June 2024 series for most Cambridge IGCSE, Cambridge International A and AS Level and Cambridge Pre–U components, and some Cambridge O Level components.

0971/41 Cambridge IGCSE (9–1) – Mark Scheme PUBLISHED May/June 2024 © Cambridge University Press & Assessment 2024 Page 2 of 11 Generic Marking Principles These general marking principles must be applied by all examiners when marking candidate answers. They should be applied alongside the specific content of the mark scheme or generic level descriptions for a question. Each question paper and mark scheme will also comply with these marking principles. GENERIC MARKING PRINCIPLE 1: Marks must be awarded in line with:  the specific content of the mark scheme or the generic level descriptors for the question  the specific skills defined in the mark scheme or in the generic level descriptors for the question  the standard of response required by a candidate as exemplified by the standardisation scripts. GENERIC MARKING PRINCIPLE 2: Marks awarded are always whole marks (not half marks, or other fractions). GENERIC MARKING PRINCIPLE 3: Marks must be awarded positively:  marks are awarded for correct/valid answers, as defined in the mark scheme. However, credit is given for valid answers which go beyond the scope of the syllabus and mark scheme, referring to your Team Leader as appropriate  marks are awarded when candidates clearly demonstrate what they know and can do  marks are not deducted for errors  marks are not deducted for omissions  answers should only be judged on the quality of spelling, punctuation and grammar when these features are specifically assessed by the question as indicated by the mark scheme. The meaning, however, should be unambiguous. GENERIC MARKING PRINCIPLE 4: Rules must be applied consistently, e.g. in situations where candidates have not followed instructions or in the application of generic level descriptors.

0971/41 Cambridge IGCSE (9–1) – Mark Scheme PUBLISHED May/June 2024 © Cambridge University Press & Assessment 2024 Page 3 of 11 GENERIC MARKING PRINCIPLE 5: Marks should be awarded using the full range of marks defined in the mark scheme for the question (however; the use of the full mark range may be limited according to the quality of the candidate responses seen). GENERIC MARKING PRINCIPLE 6: Marks awarded are based solely on the requirements as defined in the mark scheme. Marks should not be awarded with grade thresholds or grade descriptors in mind. Science–Specific Marking Principles 1 Examiners should consider the context and scientific use of any keywords when awarding marks. Although keywords may be present, marks should not be awarded if the keywords are used incorrectly. 2 The examiner should not choose between contradictory statements given in the same question part, and credit should not be awarded for any correct statement that is contradicted within the same question part. Wrong science that is irrelevant to the question should be ignored. 3 Although spellings do not have to be correct, spellings of syllabus terms must allow for clear and unambiguous separation from other syllabus terms with which they may be confused (e.g. ethane / ethene, glucagon / glycogen, refraction / reflection). 4 The error carried forward (ecf) principle should be applied, where appropriate. If an incorrect answer is subsequently used in a scientifically correct way, the candidate should be awarded these subsequent marking points. Further guidance will be included in the mark scheme where necessary and any exceptions to this general principle will be noted. 5 ‘List rule’ guidance For questions that require n responses (e.g. State two reasons …):  The response should be read as continuous prose, even when numbered answer spaces are provided.  Any response marked ignore in the mark scheme should not count towards n.  Incorrect responses should not be awarded credit but will still count towards n.  Read the entire response to check for any responses that contradict those that would otherwise be credited. Credit should not be awarded for any responses that are contradicted within the rest of the response. Where two responses contradict one another, this should be treated as a single incorrect response.  Non–contradictory responses after the first n responses may be ignored even if they include incorrect science.

0971/41 Cambridge IGCSE (9–1) – Mark Scheme PUBLISHED May/June 2024 © Cambridge University Press & Assessment 2024 Page 4 of 11 6 Calculation specific guidance Correct answers to calculations should be given full credit even if there is no working or incorrect working, unless the question states ‘show your working’. For questions in which the number of significant figures required is not stated, credit should be awarded for correct answers when rounded by the examiner to the number of significant figures given in the mark scheme. This may not apply to measured values. For answers given in standard form (e.g. a  10n) in which the convention of restricting the value of the coefficient (a) to a value between 1 and 10 is not followed, credit may still be awarded if the answer can be converted to the answer given in the mark scheme. Unless a separate mark is given for a unit, a missing or incorrect unit will normally mean that the final calculation mark is not awarded. Exceptions to this general principle will be noted in the mark scheme. 7 Guidance for chemical equations Multiples / fractions of coefficients used in chemical equations are acceptable unless stated otherwise in the mark scheme. State symbols given in an equation should be ignored unless asked for in the question or stated otherwise in the mark scheme.

0971/41 Cambridge IGCSE (9–1) – Mark Scheme PUBLISHED May/June 2024 © Cambridge University Press & Assessment 2024 Page 5 of 11 If the candidate uses different terminology to the terminology on the Mark Scheme full credit must be given if the meaning is the same. Any response that is worth more than 1 mark must be annotated by tick(s). The number of ticks should be the same as the number of marks awarded. This applies even if other annotations such as BOD or ECF are used. Ticks should be placed as near as possible to the place where the mark is awarded. Please see Practice scripts for examples. Question Answer Marks 1(a) Contact process 1 1(b) distillation 1 1(c) electrolysis 1 1(d) fractional distillation 1 1(e) fermentation 1 1(f) cracking 1 1(g) chromatography 1 Question Answer Marks 2 M1 : Cl : 17 AND 20 (1) M2 Cu+: 29 AND 28 (1) M3 33(above) and 16(below) on left hand side of symbol (1) M4 S (1) M5 2– (1) 5

0971/41 Cambridge IGCSE (9–1) – Mark Scheme PUBLISHED May/June 2024 © Cambridge University Press & Assessment 2024 Page 6 of 11 Question Answer Marks 3(a) 2Na + F2 → 2NaF(2) M1 NaF(1) Has to be the only product M2 equation completely correct(1) 2 3(b)(i) electrons move OR electrons are mobile OR electrons flow 1 3(b)(ii) M1 one shared dot and cross(1) M2 6 non–bonding electrons (either) dots or crosses on each fluorine atom to complete both octets (1) 2 3(b)(iii) M1 liquid(1) M2 BOTH melting point is below –200 °C AND boiling point is above –200 °C(1) OR BOTH –200 oC is higher than –220 °C/ melting point AND lower than –188 °C/ boiling point(1) OR –200 °C is between melting point or –220 °C and boiling point or –188 °C(1) 2 3(b)(iv) M1 ionic bonds in NaF(1) M2 attraction between molecules or intermolecular forces in F2(1) M3 weaker attraction (between particles) in F2 ORA (1) 3

0971/41 Cambridge IGCSE (9–1) – Mark Scheme PUBLISHED May/June 2024 © Cambridge University Press & Assessment 2024 Page 7 of 11 Question Answer Marks 3(c)(i) M1 breakdown by (the passage of) electricity(1) M2 of an ionic compound in molten or aqueous (state) (1) 2 3(c)(ii) 2H+ + 2e(–) → H2 M1 H+ + e(–) on left hand side(1) M2 equation fully correct(1) 2 Question Answer Marks 4(a) M1 The rate of forward reaction equals the rate of the reverse reaction(1) M2 concentrations of reactants and products are no longer changing(1) 2 4(b)(i) same number of gas moles on both sides of the equilibrium OR same number of gas molecules on both sides of the equilibrium 1 4(b)(ii) iodine particles or molecules (forced) closer together OR same number of iodine particles or molecules in a smaller volume 1 4(c) endothermic 1 4(d) M1 –1 (1) M2 zero (1) 2 4(e)(i) copper 1

0971/41 Cambridge IGCSE (9–1) – Mark Scheme PUBLISHED May/June 2024 © Cambridge University Press & Assessment 2024 Page 8 of 11 Question Answer Marks 4(e)(ii) no effect 1 4(e)(iii) (activation energy is) lower 1 Question Answer Marks 5(a)(i) M1 lead(II) nitrate(1) M2 sodium bromide / potassium bromide / ammonium bromide(1) 2 5(a)(ii) M1 filter precipitate or lead(II) bromide or solid or residue(1) M2 wash the residue with distilled water AND dry e.g. between filter papers(1) 2 5(a)(iii) Pb2+(aq) + 2Br–(aq) → PbBr2(s) M1 PbBr2 as the only product (1) M2 Pb2+ + 2Br– as the only reactants in a balanced equation(1) M3 state symbols (aq) + (aq) → (s)(1) 3 5(b) M1 acidified aqueous potassium manganate(VII) (1) M2 purple to colourless (1) 2 5(c) M1 2CoO + 4NO2 (1) M2 8H2O (1) 2

0971/41 Cambridge IGCSE (9–1) – Mark Scheme PUBLISHED May/June 2024 © Cambridge University Press & Assessment 2024 Page 9 of 11 Question Answer Marks 5(d)(i) M1 heat again and weigh again OR repeat steps 2 and 3(1) M2 until mass is constant (1) 2 5(d)(ii) M1 0.005 / 5 10–3 (1) M2 0.63 (1) M3 (0.63 / 18 =) 0.035 (1) M4 (0.035 ÷ 0.005 =) 7 (1) 4 Question Answer Marks 6(a)(i) limestone OR calcium carbonate 1 6(a)(ii) (molten) iron 1 6(a)(iii) silicon(IV) oxide OR silicon dioxide 1 6(a)(iv) coke or carbon and oxygen 1 6(a)(v) Any two from:  nitrogen  carbon dioxide  argon 2

0971/41 Cambridge IGCSE (9–1) – Mark Scheme PUBLISHED May/June 2024 © Cambridge University Press & Assessment 2024 Page 10 of 11 Question Answer Marks 6(b)(i) the temperature in the furnace is above or higher than the boiling point of zinc ORA OR the boiling point of zinc is below or less than the temperature of the furnace ORA 1 6(b)(ii) condensation / condensing 1 6(c)(i) galvanising 1 6(c)(ii) M1 zinc is more reactive than iron (1) M2 zinc is oxidised / zinc loses electrons / zinc forms positive ions / zinc forms zinc ions (1) 2 6(d)(i) amphoteric 1 6(d)(ii) Na2ZnO2 1 6(d)(iii) zinc sulfate 1 Question Answer Marks 7(a)(i) M1 C 82.76 / 12: H 17.24/1 (1) OR evaluation i.e. 6.90:17.24 M2 fractions showing division of both by smaller ie 6.9 / 6.9 and 17.24 / 6.9 OR evaluation ie 1:2.5 OR 4:10 M3 C2H5 (1) 3

0971/41 Cambridge IGCSE (9–1) – Mark Scheme PUBLISHED May/June 2024 © Cambridge University Press & Assessment 2024 Page 11 of 11 Question Answer Marks 7(a)(ii) C5H10 1 7(b) M1 any C=C with both carbons having a valency of 4(1) M2 correct displayed formula of (cis or trans) but–2–ene(1) M3 but–2–ene 3 7(c) C8H16 1 7(d)(i) structural isomers 1 7(d)(ii) M1 ethanoic acid(1) M2 methanol(1) 2 7(d)(iii) M1 Displayed formula of propanoic acid showing ALL atoms and bonds (1) M2 propanoic acid(1) 2