Cambridge AssessmentCambridge International AS A LevelCANDIDATENAMECENTRECANDIDATENUMBERNUMBERCHEMISTRY9701/52Paper 5 Planning,Analysis and EvaluationFebruary/March 20231 hour 15 minutesYou 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.This document has 12 pages.Any blank pages are indicated.DC(LK/FC)308777/3©UCLES2023[Turn over1 Aqueous iron(II)ions,Fe2*(aq),are usually kept in acidic conditions to prevent them readilyoxidising to aqueous iron(III)ions,Fe*(aq).Fe2+(ag)ions react with Ag*(aq)ions in a redox reaction.The following equilibrium is established.Fe3*(aq)+Ag(s)The concentration of Fe2*(aq)at equilibrium can be found by titration with a standard solutionof aqueous potassium manganate(VII),KMnO(aq).KMnO(aq)is deep purple in colour.Theequilibrium constant for the reaction can be found using the following equation.A student carries out the experiment using the following instructions.step 1 Add 100.0cm3 of0.200moldm-3 AgNO(aq)to 100.0cm3 of0.200moldm-3 Fe(NO)2(aq)in a 500cm3 conical flask and stopper the flask.Label the conical flask A.step 2 Leave conical flask A for four hours,shaking intermittently.Then leave conical flask Auntouched for one hour.step 3 Use a pipette to transfer 25.00cm3 of the solution from conical flask A into a clean250cm3 conical flask.Label this conical flask B.step 4 Add 5cm3 of 1.00moldm-3 NaCl(ag)to the solution in conical flask B.A white precipitateof silver chloride forms.step 5 Use a measuring cylinder to add 20cm3 of 1.00moldm-3 sulfuric acid to conical flask B.step 6 Rinse a burette and fill it with a standard solution of KMnO(aq).step 7 Add KMnO(aq)to the mixture in conical flask B until an end-point is reached.step 8 Empty conical flask B and rinse it with distilled water ready for the next titration.The student repeats the titration until concordant readings are achieved.(a)The student records their results in Table 1.1.Table 1.1roughtitration 1titration 2titration 3final burette reading/cm310.6020.3530.259.85initial burette reading/cm30.1010.7020.350.10titre/cm3©UCLES20233(i)Complete Table 1.1.(ii)Calculate a suitable mean titre to be used in the student's calculations.Show clearly how you obtain the mean titre.(b)State what is meant by a standard solution in step 6.(c)(i)Suggest why conical flask A is left for four hours in step 2.(ii)Suggest why conical flask A is not shaken during the final hour in step 2.(d)Suggest why a measuring cylinder is the most appropriate apparatus to use for measuringsulfuric acid in step 5.(e)State what the burette should be rinsed with in step 6.State the change of colour seen in the mixture in conical flask B at the end-point in step 7.to(g)The student repeats the experiment using KMnO(aq)at a lower concentration.The studentobtains a larger mean titre.Suggest one reason why a larger titre is better than a smaller titre.[1©UCLES20239701/52/F/M23