CIE Nov 2015 v4 Paper 3 Q3

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PMT 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. Marks are not given for chemical equations. 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) FB 5 is a solution containing one cation and one anion. Carry out test-tube tests tond out whether the cation in FB 5 is magnesium and whether the anion is sulfate.State what reagents you used. Record the observations you made in a table. State your conclusions about which ions are present.UCLES 2015 9701/34/O/N/15 [4] [Turn over<br /> PMT (b) FB 6 is a salt containing one cation and one anion from those listed on pages 10 and 11. (i) Place a few crystals of FB 6 in a hard-glass test-tube. Heat gently atrst and then strongly. Leave the test-tube and its contents to cool. Record all your observations below.(ii) Dissolve the remainder of FB 6 in about 20 cm3 of distilled water in a boiling tube for use in the following tests. test observations To a 1 cm depth of the solution of FB 6 in a test-tube, add a few drops of aqueous silver nitrate. To a 1 cm depth of the solution of FB 6 in a test-tube, add a few drops of dilute sulfuric acid. To a 1 cm depth of the solution of FB 6 in a test-tube, add aqueous ammonia.UCLES 2015 9701/34/O/N/15<br /> test observations PMT To a 1 cm depth of the solution of FB 6 in a boiling tube, add aqueous sodium hydroxide until in excess, then heat the mixture gently and carefully, and test any gas produced, then add a small piece of aluminium foil while the mixture is still warm. Test any gas produced. (iii) Deduce the formula of the salt in FB 6. Formula is[10] [Total: 14]UCLES 2015 9701/34/O/N/15 [Turn over<br />

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