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CIE Nov 2013 v1 Paper 3 Q3
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![Examiners For Use Qualitative Analysis At each stage of any test you are to record details of the following.colour changes seen the formation of any precipitate the solubility of such precipitates in an excess of the reagent added Where gases are released they should be identi ed by a test, described in the appropriate place in your observations. You should indicate clearly at what stage in a test a change occurs. No additional tests for ions present should be attempted. If any solution is warmed, a boiling tube MUST be used. Rinse and reuse test-tubes and boiling tubes where possible. Where reagents are selected for use in a test, the name or correct formula of the element or compound must be given. (a) FA 5 is hydrated barium chloride. FA 6 is the same iron(II) salt used in Question 1. It contains one other cation and one anion. (i) Place a small spatula measure of FA 6 into a test-tube. Dissolve the solid in about a 5 cm depth of distilled water. Use the solution for the following tests. test observations To a 1 cm depth of aqueous FA 6 in a boiling tube, add aqueous sodium hydroxide until no further change occurs, then heat the mixture carefully. Dissolve a few crystals of FA 5 in a 1 cm depth of distilled water in a test-tube. Add a 1 cm depth of FA 6, then add excess dilute hydrochloric acid to the mixture.UCLES 2013 9701/31/O/N/13<br />
Examiners For Use (ii) Identify the ions present in FA 6. cations: Fe2+ andanion:(iii) Give the ionic equation for the reaction of iron(II) ions with hydroxide ions.(iv) Place a small spatula measure of FA 6 into a hard-glass test-tube. Heat gently, then strongly, until no further change is observed. Record your observations in the space below. [7]UCLES 2013 9701/31/O/N/13 [Turn over<br />
Examiners For Use (b) FA 7, FA 8 and FA 9 are aqueous solutions. Each contains one cation and one anion. FA 3 is dilute sulfuric acid, H2SO4. 10 Mix pairs of solutions so that you can complete the table below. For each test, use 1 cm depths of each solution in clean test-tubes. Record your observations in the table. FA 7 FA 8 FA 9 FA 3 FA 7 FA 8 From your observations, complete the following statements. The anion in FA 7 isThe cation in FA 8 isThe anion in FA 9 is[6] [Total: 13]UCLES 2013 9701/31/O/N/13<br />](https://learnah.org/wp-content/uploads/2018/08/November_2013_v1_QP_-_Paper_3_CIE_Chemistry_A-level_3-0.jpg)
![(ii) ACE Correct expression for the number of moles of Interpretation residue with correct masses of anhydrous salt and 208 and answer expressed to 24 sf or correct answer and 24 sf If only one expt carried out then correct calculation for number of moles of residue expressed to 24 sig fig. (iii) ACE Correct calculation of (i)(ii) to give answer as an Interpretation integer. (should be x = 2) (c) (i) ACE Heat to constant mass (owtte) Improvements [3] Page 5 Mark Scheme Syllabus Paper GCE A LEVELOctober/November 2013 9701 31 Question Sections Indicative material Mark Total PMT (a) MMO Award IV if the ratio in expt 1 is between 6.30 and (cont) Quality 7.25. Award V If the ratio in expt 2 is between 6.30 and 7.25. Award VI If the ratio in both of experiments 1 and 2 is between 5.90 and 7.65, inclusive. [6] (b) (i) MMO Correct expression for the number of moles of water Display lost (from mass as recorded) or correct answer. (ii) ACE An attempt to scale mass loss to the mass of FA 5 Interpretation used or to calculate x separately for the two experiments. ACE Uses calculated values to comment sensibly on the Conclusion consistency the results. [3] [Total: 12] FA 6 is (NH4)2Fe(SO4)2(s); FA 7 is Na2CO3(aq); FA 8 is Pb(NO3)2(aq); FA 9 is K2CrO4(aq) (a) (i) MMO Green precipitate and ppt insoluble in excess Collection NaOH/ppt turning brown (in air / on standing). MMO (When heated with NaOH) gas / NH3 turns red litmus Decision to blue. MMO (With BaCl 2), white precipitate forms and insoluble in Collection HCl. (ii) ACE FA 6 contains ammonium ions and sulfate ions. Conclusion (correct evidence needed for each ion in the observations table). (iii) ACE 2+ Fe + 2OH Fe(OH)2 conclusionCambridge International Examinations 2013<br />
Page 6 Mark Scheme Syllabus Paper GCE A LEVELOctober/November 2013 9701 31 Question Sections Indicative material Mark Total PMT (iv) MMO Any two of collectionSolid goes paler / loses green colour (at first) and then becomes brown (on strong heating)Condensation / water vapour / steam produced (Gas/NH3) turns red litmus blue. (b) MMO FA 7 + FA 3 : collection Fizzing/effervescence and limewater goes milky. FA 8 + FA 3 and FA 8 + FA 7 : white precipitate obtained in both cases FA 9 + FA 3: (solution) turns orange FA 9 + FA 7: statement of no change/yellow solution FA 9 + FA 8: (bright) yellow precipitate/solid (formed). All three observations in the third column must be correct. [7] ACE FA 7 contains carbonate ions (evidence needed) / Conclusion CO3 FA 8 contains lead ions or barium ions (or both) (evidence needed) / Pb / Ba 2+ 2+ FA 9 contains chromate(VI) ions / CrO4 [6] [Total: 13]Cambridge International Examinations 2013<br />](https://learnah.org/wp-content/uploads/2018/08/November_2013_v1_MS_-_Paper_3_CIE_Chemistry_A-level_3-0.jpg)
