Cambridge IGCSE Chemistry (9-1) 0971 — 2025 Oct/Nov Paper 3 · Variant 2

This document has 20 pages. Any blank pages are indicated. [Turn over Cambridge IGCSE™(9–1) * 7 8 4 2 6 8 2 6 7 9 * CHEMISTRY 0971/32 Paper 3 Theory (Core) October/November 2025 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. DC (KAS) 359416 © UCLES 2025 ,










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2 0971/32/O/N/25 © UCLES 2025 1 Fig. 1.1 shows part of the Periodic Table. H B C N O He Fe Zn Ag Ca K Na I II III IV V VI VII VIII Ne Br Cl I Fig. 1.1 Answer the following questions using only the symbols of the elements in Fig. 1.1. Each symbol may be used once, more than once or not at all. Give the symbol of the element that: (a) is used as a lubricant … [1] (b) forms an ion which is present in every dilute acid … [1] (c) is a metal which does not react with steam … [1] (d) is in Period 3 and forms an ion with a charge of 1– when it reacts. … [1] [Total: 4] * 0000800000002 * ,










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3 0971/32/O/N/25 © UCLES 2025 [Turn over 2 The symbol for an atom of krypton is shown. 36 84Kr (a) Complete Table 2.1 to show the number of electrons and neutrons in one atom of 36 84Kr . Table 2.1 number of electrons number of neutrons [2] (b) Krypton is a gas at room temperature and pressure. A sample of krypton is placed in a sealed syringe with a freely moving plunger. Complete Table 2.2 to show the effect, if any, on the volume of krypton when: • the temperature of the krypton is decreased • the pressure of the krypton is increased. Use the words increases, decreases or no change in your answer. Table 2.2 change effect on the volume of krypton temperature is decreased pressure is increased [2] (c) When krypton is cooled, it becomes a liquid. Describe the arrangement of the particles in liquid krypton. Give your answer in terms of particle separation and motion. particle separation … … particle motion … … [2] [Total: 6] * 0000800000003 * ,










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4 0971/32/O/N/25 © UCLES 2025 3 (a) Table 3.1 shows the masses of ions, in mg, present in a 500 cm3 sample of contaminated water. Table 3.1 name of ion formula of ion mass of ion in 500 cm3 of contaminated water / mg ammonium 2.5 chloride Cl – 4.2 hydrogencarbonate HCO3 – 6.0 iodide I – 0.4 lithium Li+ 4.3 magnesium Mg2+ 0.8 nitrate NO3 – 8.5 phosphate PO4 3 – 0.7 potassium K+ 9.3 sulfate SO4 2 – 0.3 Answer these questions using the information from Table 3.1. (i) Name the negative ion that has the highest concentration. … [1] (ii) State the formula of the ammonium ion. … [1] (iii) Describe a test to identify the presence of chloride ions, Cl –, in a sample of water. test … observations … … [2] (iv) Calculate the mass of hydrogencarbonate ions, HCO3 – , in 200 cm3 of the contaminated water. mass = … mg [1] * 0000800000004 * ,










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5 0971/32/O/N/25 © UCLES 2025 [Turn over (b) The water sample is not suitable for use in practical chemistry. Name a process that makes the water suitable for use in practical chemistry. … [1] (c) Water extracted from a river is made suitable for drinking by filtration and then treatment with carbon followed by chlorination. (i) State why carbon is used in the treatment of water. … [1] (ii) State why water is chlorinated. … [1] (d) Fig. 3.1 shows the apparatus used to analyse a sample of water containing coloured substances and the results obtained. Fig. 3.1 (i) Name the separation method shown in Fig. 3.1. … [1] (ii) Label the solvent front in Fig. 3.1. [1] [Total: 10] * 0000800000005 * ,










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7 0971/32/O/N/25 © UCLES 2025 [Turn over 4 (a) Molecules of compound A are found in some plants. Fig. 4.1 shows the displayed formula of a molecule of compound A. C C H H H O H H H H H H H H H C H H H H H H C C C C C C C Fig. 4.1 Deduce the molecular formula of compound A to show the number of atoms of carbon, hydrogen and oxygen. … [1] (b) On Fig. 4.1, draw a circle around one part of the molecule responsible for the decolourisation of aqueous bromine. [1] (c) A different molecule found in plants has the molecular formula C10H16O2 . Complete Table 4.1 to calculate the relative molecular mass of C10H16O2 . Table 4.1 type of atom number of atoms relative atomic mass carbon 10 12 10 × 12 = 120 hydrogen 1 oxygen 16 relative molecular mass = … [2] * 0000800000007 * ,










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8 0971/32/O/N/25 © UCLES 2025 (d) Petroleum is a fossil fuel. Name one other fossil fuel. … [1] (e) Fig. 4.2 shows the names of some of the fractions obtained from petroleum using a fractionating column. lubricating oil fuel oil diesel oil / gas oil kerosene / paraffin naphtha gasoline / petrol petroleum Fig. 4.2 Using only the fractions shown in Fig. 4.2, name the fraction which contains compounds that: (i) have the longest chain length … [1] (ii) have the highest volatility … [1] (iii) are used for home heating systems. … [1] (f) Table 4.2 shows some properties of hydrocarbons found in fuel for jet engines. Table 4.2 name molecular formula melting point / °C boiling point / °C nonene C9H18 –81 147 decane C10H22 –30 174 undecane C11H24 –26 195 dodecane C12H26 –10 216 tridecane C13H28 –5 234 * 0000800000008 * ,










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9 0971/32/O/N/25 © UCLES 2025 [Turn over (i) Identify the unsaturated hydrocarbon in Table 4.2. … [1] (ii) Explain your answer in (f)(i). … … [1] (g) (i) In excess oxygen, decane undergoes complete combustion to produce carbon dioxide and one other product. Identify this other product. … [1] (ii) State one adverse effect to the environment of the production of carbon dioxide. … … [1] (h) (i) Ethanol can be used to make jet fuel. Draw the displayed formula of ethanol. Show all the atoms and all the bonds. [2] (ii) Ethanol can be manufactured from ethene and one other reactant. Name the other reactant, and state the temperature and pressure used. reactant … temperature … °C pressure … atm [3] [Total: 17] * 0000800000009 * ,










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10 0971/32/O/N/25 © UCLES 2025 5 This question is about elements in different groups of the Periodic Table and their compounds. (a) Nitrogen is in Group V of the Periodic Table. Explain why nitrogen is placed in Group V. Give your answer in terms of electronic configuration. … [1] (b) Tellurium is in Group VI of the Periodic Table. Table 5.1 shows the melting point and the boiling point of tellurium. Table 5.1 melting point / °C 450 boiling point / °C 988 Use Table 5.1 to deduce the physical state of tellurium at 650 °C. Give a reason for your answer. physical state … reason … … [2] (c) Bromine is in Group VII of the Periodic Table. Give the colour and state of bromine at room temperature and pressure. colour … state … [2] (d) When a sample of sodium is added to a large container of cold water, a chemical reaction occurs. (i) Describe what is observed when sodium is added to water. … … … … … … [3] * 0000800000010 * ,










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11 0971/32/O/N/25 © UCLES 2025 [Turn over (ii) Complete the word equation for the reaction of sodium with water. sodium + water … … + hydrogen [1] (e) Sodium carbonate reacts with sulfuric acid to form sodium sulfate, carbon dioxide and one other product. Complete the symbol equation for this reaction. Na2CO3 + … Na2SO4 + CO2 + … [2] (f) Solid sodium hydroxide is slowly added to distilled water containing a few drops of thymolphthalein and the mixture is stirred. (i) State the colour change observed when sodium hydroxide is added to water containing thymolphthalein. from … to … [2] (ii) Aqueous sodium hydroxide is an alkali. Complete the sentence about an alkali using one of the words from the list. acid base indicator salt An alkali is a soluble … . [1] (g) Fluorine is in Group VII of the Periodic Table. Fluorine reacts with sodium to form the ionic compound sodium fluoride. Complete the dot-and-cross diagram in Fig. 5.1 for sodium fluoride to show: • the electronic configuration for each ion • the charge on each ion. Na … F … Fig. 5.1 [3] [Total: 17] * 0000800000011 * ,









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12 0971/32/O/N/25 © UCLES 2025 6 This question is about metals. (a) Iron is extracted from its ore using carbon in a blast furnace. Aluminium is extracted from its ore using electrolysis. (i) Name the main ore of aluminium. … [1] (ii) Explain why aluminium is not extracted from its ore by reduction with carbon. Give your answer in terms of the reactivity series. … … [1] (iii) An equation for the reduction of iron(III) oxide using carbon is shown. 2Fe2O3 + 3C 4Fe + 3CO2 Explain how this equation shows that iron(III) oxide is reduced. … … [1] (b) Iron is made into stainless steel. Stainless steel is an alloy that resists rusting. (i) State what is meant by the term alloy. … … [2] (ii) Name the two substances required for iron to rust. … and … [2] (iii) State the chemical name for rust. … [2] * 0000800000012 * ,









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13 0971/32/O/N/25 © UCLES 2025 [Turn over (c) Table 6.1 shows the observations when four different metals are added separately to dilute hydrochloric acid. Table 6.1 metal observations Mn bubbles of gas given off quickly and the temperature of the mixture increases slowly Fe a few bubbles of gas given off very slowly and the temperature of the mixture increases very slowly Sr many bubbles of gas given off very quickly and the temperature of the mixture increases rapidly Nb no bubbles of gas given off and no temperature increase of the mixture (i) Put the four metals in order of their reactivity. Put the least reactive metal first. least reactive most reactive [2] (ii) Complete the word equation for the reaction of strontium with hydrochloric acid. strontium + hydrochloric acid … … + … [2] [Total: 13] * 0000800000013 * ,









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14 0971/32/O/N/25 © UCLES 2025 7 Fig. 7.1 shows the apparatus used to pass electricity through molten magnesium chloride using platinum electrodes. power supply crucible + – Fig. 7.1 (a) Name the process shown in Fig. 7.1. … [1] (b) Label the electrolyte in Fig. 7.1. [1] (c) Name the product formed at the anode. … [1] (d) The electrodes are made of platinum. (i) State one property of platinum that makes it suitable for use as an electrode. … [1] (ii) Suggest a non-metal that could be used as the electrodes. … [1] (e) State whether the process shown in Fig. 7.1 produces a physical or chemical change. Explain your answer. type of change … explanation … … [1] * 0000800000014 * ,









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15 0971/32/O/N/25 © UCLES 2025 [Turn over (f) Magnesium chloride, MgCl 2, exists in different forms. Draw one line from each form of magnesium chloride to its description. form of magnesium chloride description solid MgCl 2 chemically combined with water MgCl 2 dissolved in water solid MgCl 2 containing no water aqueous MgCl 2 anhydrous MgCl 2 hydrated MgCl 2 [2] [Total: 8] * 0000800000015 * ,









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16 0971/32/O/N/25 © UCLES 2025 8 Excess dilute hydrochloric acid is added to aqueous sodium sulfide to form aqueous sodium chloride and gaseous hydrogen sulfide, H2S. 2HCl (aq) + Na2S(aq) 2NaCl (aq) + H2S(g) Fig. 8.1 shows the total volume of hydrogen sulfide gas, H2S, produced as the reaction proceeds. 0 0 25 50 75 100 125 150 20 40 60 time / s total volume of H2S / cm3 80 100 120 140 Fig. 8.1 (a) Use Fig. 8.1 to determine the total volume of H2S produced when the reaction is complete. total volume of H2S = … cm3 [1] * 0000800000016 * ,









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17 0971/32/O/N/25 © UCLES 2025 (b) The reaction is repeated using hydrochloric acid of a higher concentration. All other conditions stay the same. State the effect, if any, on: (i) the time taken for the reaction to finish … [1] (ii) the total volume of H2S produced when the reaction is complete. … [1] (c) Fig. 8.2 shows the reaction pathway diagram for the reaction of dilute hydrochloric acid with aqueous sodium sulfide. energy 2HCl + Na2S 2NaCl + H2S progress of reaction Fig. 8.2 Deduce the type of energy change shown in the diagram in Fig. 8.2. Explain your answer. … … … … [2] [Total: 5] * 0000800000017 * ,









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19 0971/32/O/N/25 © UCLES 2025 BLANK PAGE 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. * 0000800000019 * ,









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20 0971/32/O/N/25 © UCLES 2025 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 – * 0000800000020 * ,










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This document consists of 13 printed pages. © Cambridge University Press & Assessment 2025 [Turn over Cambridge IGCSE™ (9–1) CHEMISTRY 0971/32 Paper 3 Theory (Core) October/November 2025 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 October/November 2025 series for most Cambridge IGCSE, Cambridge International A and AS Level components, and some Cambridge O Level components.

0971/32 Cambridge IGCSE (9–1) – Mark Scheme PUBLISHED October/November 2025 © Cambridge University Press & Assessment 2025 Page 2 of 13 Generic Marking Principles These general marking principles must be applied by all examiners when marking candidate answers. They should be applied alon gside 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.

0971/32 Cambridge IGCSE (9–1) – Mark Scheme PUBLISHED October/November 2025 © Cambridge University Press & Assessment 2025 Page 3 of 13 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 thre sholds 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 fro m 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.

0971/32 Cambridge IGCSE (9–1) – Mark Scheme PUBLISHED October/November 2025 © Cambridge University Press & Assessment 2025 Page 4 of 13 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.

0971/32 Cambridge IGCSE (9–1) – Mark Scheme PUBLISHED October/November 2025 © Cambridge University Press & Assessment 2025 Page 5 of 13 Annotations guidance for centres Examiners use a system of annotations as a shorthand for communicating their marking decisions to one another. Examiners are trained during the standardisation process on how and when to use annotations. The purpose of annotations is to inform the standard isation and monitoring processes and guide the supervising examiners when they are checking the work of examiners within their team. The meaning of annotations and how they are used is specific to each component and is understood by all examiners who mark the component. We publish annotations in our mark schemes to help centres understand the annotations they may see on copies of scripts. Note that there may not be a direct correlation between the number of annotations on a script and the mark awarded. Similarly, the use of an annotation may not be an indication of the quality of the response. The annotations listed below were available to examiners marking this component in this series. Annotations Annotation Meaning information missing or insufficient for credit benefit of doubt given contradition in response, mark not awarded incorrect point or mark not awarded key point attempted / working towards marking point / incomplete answer / response seen but not credited / blank page seen error carried forward applied incorrect or insufficient response, mark not awarded response has not answered question incorrect point or mark not awarded blank page seen

0971/32 Cambridge IGCSE (9–1) – Mark Scheme PUBLISHED October/November 2025 © Cambridge University Press & Assessment 2025 Page 6 of 13 Annotation Meaning correct point of mark awarded

0971/32 Cambridge IGCSE (9–1) – Mark Scheme PUBLISHED October/November 2025 © Cambridge University Press & Assessment 2025 Page 7 of 13 Question Answer Marks 1(a) C 1 1(b) H 1 1(c) Ag 1 1(d) Cl 1 Question Answer Marks 2(a) number of electrons 36 number of neutrons 48 2 2(b) change effect on the volume of krypton temperature is decreased decreases pressure is increased decreases 2 2(c) separation: close together / touching / packed / not separated (1) motion: sliding over each other / random (1) 2 Question Answer Marks 3(a)(i) nitrate 1 3(a)(ii) NH4+ 1

0971/32 Cambridge IGCSE (9–1) – Mark Scheme PUBLISHED October/November 2025 © Cambridge University Press & Assessment 2025 Page 8 of 13 Question Answer Marks 3(a)(iii) (dilute nitric acid and aqueous) silver nitrate (1) white precipitate (1) 2 3(a)(iv) 2.4 (mg) 1 3(b) distillation 1 3(c)(i) removes (bad) tastes / odours 1 3(c)(ii) kill microbes 1 3(d)(i) (paper) chromatography 1 3(d)(ii) solvent front labelled correctly 1 Question Answer Marks 4(a) C10H18O 1 4(b) C=C circled 1 4(c) 168 2 4(d) coal / natural gas 1 4(e)(i) lubricating oil 1

0971/32 Cambridge IGCSE (9–1) – Mark Scheme PUBLISHED October/November 2025 © Cambridge University Press & Assessment 2025 Page 9 of 13 Question Answer Marks 4(e)(ii) gasoline / petrol 1 4(e)(iii) fuel oil 1 4(f)(i) nonene 1 4(f)(ii) its name ends in -ene / its formula matches CnH2n 1 4(g)(i) water / H2O 1 4(g)(ii) increased global warming / climate change 1 4(h)(i) 2 carbons AND 1 OH group (1) all structure is correct (1) 2 4(h)(ii) steam (1) 300 (°C) (1) 60 (atm) (1) 3

0971/32 Cambridge IGCSE (9–1) – Mark Scheme PUBLISHED October/November 2025 © Cambridge University Press & Assessment 2025 Page 10 of 13 Question Answer Marks 5(a) it has 5 electrons in its outer electron shell 1 5(b) liquid (1) between melting and boiling point (1) 2 5(c) red-brown (1) liquid (1) 2 5(d)(i) any 3 from: • moves • floats • melts / turns into a sphere/ball • effervescence/bubbles/fizzing • pops / explodes • (yellow-orange) flame • solid gets smaller / disappears • gets hot / temperature rise / heat produced / temperature (becomes) high(er) 3 5(d)(ii) sodium hydroxide 1 5(e) Na2CO3 + H2SO4 (1) → Na2SO4 + CO2 + H2O (1) 2 5(f)(i) colourless (1) to blue (1) 2 5(f)(ii) base 1

0971/32 Cambridge IGCSE (9–1) – Mark Scheme PUBLISHED October/November 2025 © Cambridge University Press & Assessment 2025 Page 11 of 13 Question Answer Marks 5(g) Na+ ion correct (1) F– ion correct (1) both charges are correct (1) 3 Question Answer Marks 6(a)(i) bauxite 1 6(a)(ii) aluminium is more reactive (than carbon in the reactivity series) 1 6(a)(iii) the iron(III) oxide has lost oxygen (atom(s)) 1 6(b)(i) mixture (1) of a metal with other elements (1) 2 6(b)(ii) water (1) oxygen (1) 2 6(b)(iii) hydrated (1) iron(III) oxide (1) 2 6(c)(i) Nb → Fe → Mn → Sr 2

0971/32 Cambridge IGCSE (9–1) – Mark Scheme PUBLISHED October/November 2025 © Cambridge University Press & Assessment 2025 Page 12 of 13 Question Answer Marks 6(c)(ii) strontium chloride (1) hydrogen (1) 2 Question Answer Marks 7(a) electrolysis 1 7(b) the molten mixture labelled 1 7(c) chlorine / Cl 2 1 7(d)(i) conducts electricity OR inert 1 7(d)(ii) carbon / graphite 1 7(e) chemical change AND new substances are made 1 7(f) aqueous MgCl2 solid MgCl2 chemically combined with water anhydrous MgCl2 MgCl2 dissolved in water hydrated MgCl2 solid MgCl2 containing no water 2

0971/32 Cambridge IGCSE (9–1) – Mark Scheme PUBLISHED October/November 2025 © Cambridge University Press & Assessment 2025 Page 13 of 13 Question Answer Marks 8(a) 132.5 (cm3) 1 8(b)(i) decreases / less (time) 1 8(b)(ii) no change 1 8(c) exothermic (1) energy (level) of products below that of reactants (1) ORA 2