Cambridge A Level Chemistry 9701 — 2025 Oct/Nov Paper 5 · Variant 3

This document has 12 pages. Any blank pages are indicated. [Turn over Cambridge International AS & A Level * 5 5 9 5 0 1 0 4 7 8 * CHEMISTRY 9701/53 Paper 5 Planning, Analysis and Evaluation 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 30. ● The number of marks for each question or part question is shown in brackets [ ]. ● The Periodic Table is printed in the question paper. ● Important values, constants and standards are printed in the question paper. DC (DE/FC) 340824/3 © UCLES 2025 ,










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3 9701/53/O/N/25 © UCLES 2025 [Turn over 1 The concentration of aqueous chloride ions can be found by titration with aqueous silver nitrate, AgNO3(aq). Ag+(aq) + Cl –(aq) AgCl(s) The indicator used is aqueous potassium chromate(VI), K2CrO4(aq). As AgNO3(aq) is added to aqueous chloride ions, a white precipitate of AgCl(s) is formed. When all the chloride ions have reacted, further addition of AgNO3(aq) leads to the formation of a red precipitate of silver chromate(VI), Ag2CrO4(s). The first appearance of the red precipitate shows the end-point of the titration. A student carries out an experiment to determine the number of molecules of water of crystallisation, x, in hydrated barium chloride, BaCl 2•xH2O(s). (a) The student makes 250.0 cm3 of 0.0500 mol dm–3 AgNO3(aq) to use for the titration. (i) Calculate the mass of solid silver nitrate, AgNO3(s), needed to make 250.0 cm3 of 0.0500 mol dm–3 AgNO3(aq). Give your answer to two decimal places. mass of AgNO3(s) = … g [1] (ii) Describe how the student should make 250.0 cm3 of 0.0500 mol dm–3 AgNO3(aq) starting from the mass of AgNO3(s) calculated in (a)(i) in a 50 cm3 beaker. Give the name and size of any key apparatus used. Write your answer using a series of numbered steps. … … … … … … … [3] * 0000800000003 * ,










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4 9701/53/O/N/25 © UCLES 2025 (b) The student uses the following method. step 1 Dissolve 1.58 g of BaCl 2•xH2O(s) to form 250 cm3 of aqueous solution. Label this solution A. step 2 Transfer 20.0 cm3 of solution A into a conical flask. step 3 Add aqueous sodium sulfate, Na2SO4(aq), to the flask and swirl the mixture to remove barium ions from the solution. step 4 Add 2–3 drops of K2CrO4(aq) indicator to the flask. step 5 Titrate the contents of the flask against 0.0500 mol dm–3 AgNO3(aq). step 6 Repeat steps 2 to 5 to collect sufficient data for analysis. (i) Suggest a suitable piece of apparatus for transferring 20.0 cm3 of solution A in step 2. … [1] (ii) Suggest why barium ions are removed in step 3 before performing the titration. … … [1] (iii) Suggest why chemically resistant gloves should be worn to carry out step 4. … [1] (c) The student’s results are shown in Table 1.1. Table 1.1 rough titration titration 1 titration 2 titration 3 burette reading (final) / cm3 20.10 40.55 20.75 20.90 burette reading (initial) / cm3 0.00 20.25 0.05 0.30 titre / cm3 20.10 20.30 20.70 20.60 The student uses the titres from titrations 2 and 3 shown in Table 1.1 to calculate a mean titre value of 20.65 cm3. (i) Explain why only these two values are used. … [1] * 0000800000004 * ,










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5 9701/53/O/N/25 © UCLES 2025 [Turn over (ii) Calculate the percentage error in the titre volume for titration 3. Show your working. percentage error = … [1] (d) The equation for the reaction of silver nitrate with barium chloride is shown. 2AgNO3(aq) + BaCl 2(aq) Ba(NO3)2(aq) + 2AgCl(s) (i) Calculate the amount, in mol, of AgNO3(aq) in the mean titre of 20.65 cm3. amount of AgNO3 = … mol [1] (ii) Calculate the amount, in mol, of BaCl 2(aq) in 250 cm3 of solution A. amount of BaCl 2 = … mol [1] (iii) Calculate the value of x in the formula BaCl 2•xH2O. x = … [2] * 0000800000005 * ,










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6 9701/53/O/N/25 © UCLES 2025 (e) Another student uses a different experimental method to check the value of x obtained by the method described in (b). Give a brief description of another method, not involving titration, that could be used to determine the value of x in the formula BaCl 2•xH2O(s). Write your answer using a series of numbered steps. Your plan should include details of the following: • the apparatus and method you would use • the measurements you would make. You are provided with standard laboratory apparatus. … … … … … … … … … [3] [Total: 16] * 0000800000006 * ,










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7 9701/53/O/N/25 © UCLES 2025 [Turn over 2 Effusion is the process in which a gas escapes through a small hole. A student investigates the relationship between rate of effusion and relative molar mass of a gas using the apparatus shown in Fig. 2.1. gas syringe side-arm tube plunger gas being tested three-way tap aluminium foil with small hole Fig. 2.1 The following method is used: step 1 Turn the tap and remove any gas from the syringe through the side-arm tube, by pushing in the plunger. step 2 Add 50 cm3 of the gas being tested to the syringe through the side-arm tube. step 3 Remove the gas from the syringe, through the side-arm tube, by pushing in the plunger. step 4 Add 70 cm3 of the gas being tested to the syringe through the side-arm tube. step 5 Turn the tap to connect the syringe to the tube with the aluminium foil and small hole. step 6 Allow the syringe plunger to fall and start a timer when the volume of gas in the syringe reaches 60 cm3. step 7 Stop the timer when the volume of gas in the syringe reaches 10 cm3. Record the time taken. step 8 Repeat steps 1 to 7 with different gases. * 0000800000007 * ,










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8 9701/53/O/N/25 © UCLES 2025 (a) Suggest why the student adds 50 cm3 of the gas being tested to the syringe in step 2 and then removes this gas in step 3. … … [1] (b) The student’s results are shown in Table 2.1. Table 2.1 gas hydrogen, H2 helium, He neon, Ne argon, Ar krypton, Kr relative molar mass, M 2.0 4.0 20.2 39.9 83.8 M 1 time taken / s 10.8 15.3 34.5 39.7 70.4 rate of effusion / cm3 s–1 rate of effusion = volume of gas time taken (i) Complete Table 2.1. Give the values for M 1 to three significant figures. Give the values for rate of effusion to two decimal places. [2] (ii) Identify the dependent variable in this experiment. … [1] (iii) Identify a variable, other than temperature, that is controlled when carrying out this experiment. … [1] * 0000800000008 * ,










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9 9701/53/O/N/25 © UCLES 2025 [Turn over (c) Plot a graph on the grid in Fig. 2.2 to show the relationship between rate of effusion and M 1 . Use a cross (×) to plot each data point. Draw a suitable line of best fit. 0.0 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.5 1.0 1.5 2.0 rate of effusion / cm3 s–1 2.5 3.0 3.5 4.0 4.5 5.0 M 1 Fig. 2.2 [2] * 0000800000009 * ,










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10 9701/53/O/N/25 © UCLES 2025 (d) Circle one point on the graph in Fig. 2.2 which you consider to be most anomalous. Suggest one reason for this anomaly. Assume there is no error in M 1 . … … [1] (e) Graham’s law of effusion can be expressed as: the rate of effusion of a gas is proportional to M 1 . State whether or not the student’s results support Graham’s law of effusion. Explain your answer, using the graph in Fig. 2.2. … … [1] (f) Suggest how the position of the plotted points relative to the line of best fit in Fig. 2.2 is related to the reliability of the results. … … [1] (g) The student then repeats this method to determine the value of M of a sample of natural gas. The time recorded in step 7 is 31.6 s. (i) Use the graph in Fig. 2.2 and the student’s result to calculate the value of M for this sample. M = … [2] (ii) Natural gas is a mixture of mainly methane, CH4, with small amounts of other gases. Suggest what your calculated value of the M of natural gas in (g)(i) tells you about the other gases in the mixture. … … [1] * 0000800000010 * ,










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11 9701/53/O/N/25 © UCLES 2025 (h) The experiment described in (g) is repeated at a higher temperature. Suggest how the rate of effusion for this sample of natural gas would change, if at all. Explain your answer. effect on the rate of effusion … explanation … … [1] [Total: 14] Important values, constants and standards molar gas constant R = 8.31 J K–1 mol–1 Faraday constant F = 9.65 × 104 C mol–1 Avogadro constant L = 6.02 × 1023 mol–1 electronic charge e = –1.60 × 10–19 C molar volume of gas Vm = 22.4 dm3 mol–1 at s.t.p. (101 kPa and 273 K) Vm = 24.0 dm3 mol–1 at room conditions ionic product of water Kw = 1.00 × 10–14 mol2 dm–6 (at 298 K (25 °C)) specific heat capacity of water c = 4.18 kJ kg–1 K–1 (4.18 J g–1 K–1) * 0000800000011 * ,









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12 9701/53/O/N/25 © UCLES 2025 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. Group The Periodic Table of Elements 1 H hydrogen 1.0 2 He helium 4.0 1 2 13 14 15 16 17 18 3 4 5 6 7 8 9 10 11 12 3 Li lithium 6.9 4 Be beryllium 9.0 atomic number atomic symbol Key name relative atomic mass 11 Na sodium 23.0 12 Mg magnesium 24.3 19 K potassium 39.1 20 Ca calcium 40.1 37 Rb rubidium 85.5 38 Sr strontium 87.6 55 Cs caesium 132.9 56 Ba barium 137.3 87 Fr francium – 88 Ra radium – 5 B boron 10.8 13 Al aluminium 27.0 31 Ga gallium 69.7 49 In indium 114.8 81 Tl thallium 204.4 6 C carbon 12.0 14 Si silicon 28.1 32 Ge germanium 72.6 50 Sn tin 118.7 82 Pb lead 207.2 22 Ti titanium 47.9 40 Zr zirconium 91.2 72 Hf hafnium 178.5 104 Rf rutherfordium – 23 V vanadium 50.9 41 Nb niobium 92.9 73 Ta tantalum 180.9 105 Db dubnium – 24 Cr chromium 52.0 42 Mo molybdenum 95.9 74 W tungsten 183.8 106 Sg seaborgium – 25 Mn manganese 54.9 43 Tc technetium – 75 Re rhenium 186.2 107 Bh bohrium – 26 Fe iron 55.8 44 Ru ruthenium 101.1 76 Os osmium 190.2 108 Hs hassium – 27 Co cobalt 58.9 45 Rh rhodium 102.9 77 Ir iridium 192.2 109 Mt meitnerium – 28 Ni nickel 58.7 46 Pd palladium 106.4 78 Pt platinum 195.1 110 Ds darmstadtium – 29 Cu copper 63.5 47 Ag silver 107.9 79 Au gold 197.0 111 Rg roentgenium – 30 Zn zinc 65.4 48 Cd cadmium 112.4 80 Hg mercury 200.6 112 Cn copernicium – 114 Fl flerovium – 116 Lv livermorium – 7 N nitrogen 14.0 15 P phosphorus 31.0 33 As arsenic 74.9 51 Sb antimony 121.8 83 Bi bismuth 209.0 8 O oxygen 16.0 16 S sulfur 32.1 34 Se selenium 79.0 52 Te tellurium 127.6 84 Po polonium – 9 F fluorine 19.0 17 Cl chlorine 35.5 35 Br bromine 79.9 53 I iodine 126.9 85 At astatine – 10 Ne neon 20.2 18 Ar argon 39.9 36 Kr krypton 83.8 54 Xe xenon 131.3 86 Rn radon – 113 Nh nihonium – 115 Mc moscovium – 117 Ts tennessine – 118 Og oganesson – 21 Sc scandium 45.0 39 Y yttrium 88.9 57–71 lanthanoids 89–103 actinoids 57 La lanthanum 138.9 89 Ac lanthanoids actinoids actinium – 58 Ce cerium 140.1 90 Th thorium 232.0 59 Pr praseodymium 140.9 91 Pa protactinium 231.0 60 Nd neodymium 144.2 92 U uranium 238.0 61 Pm promethium – 93 Np neptunium – 62 Sm samarium 150.4 94 Pu plutonium – 63 Eu europium 152.0 95 Am americium – 64 Gd gadolinium 157.3 96 Cm curium – 65 Tb terbium 158.9 97 Bk berkelium – 66 Dy dysprosium 162.5 98 Cf californium – 67 Ho holmium 164.9 99 Es einsteinium – 68 Er erbium 167.3 100 Fm fermium – 69 Tm thulium 168.9 101 Md mendelevium – 70 Yb ytterbium 173.1 102 No nobelium – 71 Lu lutetium 175.0 103 Lr lawrencium – * 0000800000012 * ,









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This document consists of 10 printed pages. © Cambridge University Press & Assessment 2025 [Turn over Cambridge International AS & A Level CHEMISTRY 9701/53 Paper 5 Planning, Analysis and Evaluation October/November 2025 MARK SCHEME Maximum Mark: 30 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.

9701/53 Cambridge International AS & A Level – Mark Scheme PUBLISHED October/November 2025 © Cambridge University Press & Assessment 2025 Page 2 of 10 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.

9701/53 Cambridge International AS & A Level – Mark Scheme PUBLISHED October/November 2025 © Cambridge University Press & Assessment 2025 Page 3 of 10 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.

9701/53 Cambridge International AS & A Level – Mark Scheme PUBLISHED October/November 2025 © Cambridge University Press & Assessment 2025 Page 4 of 10 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.

9701/53 Cambridge International AS & A Level – Mark Scheme PUBLISHED October/November 2025 © Cambridge University Press & Assessment 2025 Page 5 of 10 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 Unclear response Information missing or insufficient for credit Benefit of the doubt given Contradiction in response, mark not awarded Incorrect point or mark not awarded Part of the correct answer has been seen. Full credit has not been awarded. Error carried forward applied Highlighted text Highlighting areas of text Incorrect or insufficient point ignored while marking the rest of the response Rounding error

9701/53 Cambridge International AS & A Level – Mark Scheme PUBLISHED October/November 2025 © Cambridge University Press & Assessment 2025 Page 6 of 10 Annotation Meaning Blank page or part of script seen Error in number of significant figures Transcription error Correct point or mark awarded

9701/53 Cambridge International AS & A Level – Mark Scheme PUBLISHED October/November 2025 © Cambridge University Press & Assessment 2025 Page 7 of 10 Question Answer Marks 1(a)(i) 2.12 g 1 1(a)(ii) M1 add a (small) volume of (distilled) water (to the small beaker) AND dissolve the solid / AgNO3 (s) M2 Transfer the solution and washings (using a funnel) AND into a 250 cm3 volumetric flask. M3 Make up to the (calibration) mark / line with distilled water. AND then invert the (stoppered) flask (several times) 3 1(b)(i) (20(.0) cm3) pipette. 1 1(b)(ii) barium (ions) could react with chromate (ions). 1 1(b)(iii) Potassium chromate(VI) / K2CrO4(aq) is an irritant / corrosive 1 1(c)(i) They are (the only ones that are) concordant. 1 1(c)(ii) 2 0.05 100 20.60   = 0.48(54%) Correct working must be shown. 1 1(d)(i) 20.65  0.05 / 1000 = 0.00103(25) 1 1(d)(ii) = ((d)(i) / 2) *(250 / 20) = (d)(i)  6.25 1

9701/53 Cambridge International AS & A Level – Mark Scheme PUBLISHED October/November 2025 © Cambridge University Press & Assessment 2025 Page 8 of 10 Question Answer Marks 1(d)(iii) M1 Mr = 1.58 / (d)(ii) M2 x= (M1 – 208.3) / 18 AND x must be an integer. Some working must be shown. 2 1(e) Heat to drive off water of crystallisation. M1 Apparatus 1 Bunsen burner. 2 Crucible (supported by pipeclay triangle) M2 Measurements 1 Measure mass of crucible (+ lid) (empty). 2 Measure mass crucible (+ lid) + solid before heating 3 Measure mass of crucible (+ lid) + residue (after heating.) M3 Key step in method • Description of heat to constant mass. OR Produce a suitable precipitate using a viable reaction. M1 Apparatus and method • Chooses suitable reagent. • Filter the precipitate. • Wash and (allow to) dry M2 Measurements • Measure mass of hydrated barium chloride used. • Measure mass of precipitate. M3 Key step in method • Description of dry to constant mass. 3

9701/53 Cambridge International AS & A Level – Mark Scheme PUBLISHED October/November 2025 © Cambridge University Press & Assessment 2025 Page 9 of 10 Question Answer Marks 2(a) To ensure no air / other gas remains in the syringe 1 2(b)(i) 1 Mr 0.707 0.500 0.222 0.158 0.109 Rate of effusion /cm3s-1 4.63 3.27 1.45 1.26 0.71 2 2(b)(ii) Time (taken). 1 2(b)(iii) size of hole 1 2(c) M1 all 5 points plotted correctly. M2 Straight line of best fit drawn 2 2(d) Point most anomalous to the plotted line of best fit circled. AND If point above LOBF (Measured rate of effusion is higher than the true rate predicted by LOBF.) for this point … measured / recorded (effusion) time < true / actual time OR If point below LOBF (Measured rate of effusion is lower than the true rate predicted by LOBF.) for this point … measured / recorded (effusion) time > true / actual time 1 2(e) Yes AND The graph / LOBF… is a straight-line AND it goes through the origin. 1 2(f) The results are not reliable as there is an anomalous result. 1

9701/53 Cambridge International AS & A Level – Mark Scheme PUBLISHED October/November 2025 © Cambridge University Press & Assessment 2025 Page 10 of 10 Question Answer Marks 2(g)(i) M1 Effusion rate = 50/31.6 = (1.58) Correct value for 1 Mr read from x-axis 1 M2 Value correctly converted to M. 1 2(g)(ii) If calculated M > 16 (The average) M (of the other components) is greater than 16 / calculated value for g(i). 1 2(h) (Rate of effusion) increases AND (At higher temperature) gas particles move more quickly. 1