Classified Chemistry IGCSE1 Paper_6_Topic 1 Topic 1 Laboratory apparatus Safety in laboratory Methods of purification Separation of mixtures Chromatography 1 - Experimental technique Mostafa Barakat (0100 165 44 62) Classified Chemistry IGCSE 2 Paper_6_Topic 1 (1) June 2002 Q (2_b, c) 2 The label shows the substances present in a bottle of lemon drink. (b) How could a sample of pure water be obtained from the drink? Heat the lemon drink ............................................................................................................................ condense water vapour (simple distillation) ............................................................................................................................ ............................................................................................................................ ....................................................................................................................... [2] (c) Describe an experiment you could carry out to show that the drink contained two different yellow substances by chromatography ............................................................................................................................ put the drink on chromatogram paper ............................................................................................................................ add suitable solvent (water of ethanol) ............................................................................................................................ measure the distance moved by solvent ............................................................................................................................ ............................................................................................................................ ........................................................................................................................[3] 1 - Experimental technique Mostafa Barakat (0100 165 44 62) Classified Chemistry IGCSE Paper_6_Topic 1 3 (2) June 2003 Q (1) 1 Look at the diagrams of common laboratory apparatus. A Mortar B Stirrer C Tripod D Bunsen Burner (a) Complete the empty boxes to identify the pieces of apparatus labelled. [4] 1 - Experimental technique Mostafa Barakat (0100 165 44 62) ................................................................................................................................ 2) add excess of dilute hydrochloric acid to beach sand ...........[6] 1 .......................................................................................................................................................................................... 4) wash the sand to remove the traces of solution ................................ ....................................................................................................................................................................... Plan an investigation to find out the percentage of shell material in a given sample of beach sand................................................................................................................................................................................................................................................................................................................................................ 6) weight the sand ................................................................................ 3) filter to remove sand from the solution of calcium chloride ..........................................................................mass of sand ................Experimental technique Mostafa Barakat (0100 165 44 62) ..........................[1] (3) June 2003 Q (6) Beach sand is a mixture of sand and broken shells (calcium carbonate)................................................................................................................ Calcium carbonate reacts with dilute hydrochloric acid to form a solution of calcium chloride................................................................. % of shell = (mass of shell / mass of beach sand) X 100 .Classified Chemistry IGCSE 4 Paper_6_Topic 1 (b) What name is given to the separation method in C? Filteration ..................................................................................................... 5) dry residue (sand) ...................................................[1] (c) Which apparatus would be most suitable to obtain crystals from an aqueous solution of copper(II) sulphate? D liquid is evapourated to obtain crystals ................. 1) take a 10 g of beach sand in a beaker ................................................................................... ..................................................................................................................... .. mass of shell = mass of beach sand . .........................Experimental technique Mostafa Barakat (0100 165 44 62) ...................................................[2] 1 ........................... b) 1 An experiment was carried out to find the pH of samples of soil from a farmer’s field (a) Identify the pieces of apparatus labelled Funnel A.... ……………………………………………………………………………………… pipette C.......Classified Chemistry IGCSE 5 Paper_6_Topic 1 (4) June 2004 Q (1_a............................................................... ……………………………………………………………………………………… Flask B.................... ……………………………………………………………………………………… [3] (b) Why was the soil crushed? to increase the surface area to increase the rate of reaction ........... .......................................... ................................................. A few drops of cold water were added................ Step 3 The filtrate was concentrated....... [2] 1 ............ Step 2 The mixture was filtered..................................[1] (c) How was Step 3 carried out? heating / evapurate .................................................................................................................... Step 1 The jam was boiled with water......... Step 4 The concentrate was analysed by chromatography.......... clamp pipette Bunsen burner (a) Complete the empty boxes to identify the pieces of apparatus labelled.......[1] (d) Draw a diagram to show the possible paper chromatogram obtained in Step 4........ The solid expanded and gave off steam................... [3] (6) June 2006 Q (2) 2 A sample of orange fruit jam was investigated to check the three colourings present........... b) 1 A small piece of limestone was heated strongly and left to cool..................Experimental technique Mostafa Barakat (0100 165 44 62) ........Classified Chemistry IGCSE Paper_6_Topic 1 6 (5) June 2005 Q (1_a........ (a) What was the purpose of Step 1? to extract the colour .....................................[1] (b) Why was the mixture filtered? to remove solid (insoluble impurites) .... ................[1] (c) How could the purity of the ethanol collected be checked? measure the boiling point ............................................................ (a) Name each piece of apparatus................ ……………………………………………………………………………………… tripod C.................................. ……………………………………………………………………………………… [3] (b) What is the purpose of D? to condense the vapour ..............Classified Chemistry IGCSE 7 Paper_6_Topic 1 (7) June 2007 Q (1) 1 A mixture of ethanol and water can be separated by fractional distillation..................................................... thermometer A... The apparatus below can be used to carry out such a separation in the laboratory..................................[1] 1 ........ ……………………………………………………………………………………… beaker B.....Experimental technique Mostafa Barakat (0100 165 44 62) ..... ...............................Experimental technique Mostafa Barakat (0100 165 44 62) ............................................[1] (c) Which amino acid sample contains more than one amino acid? Explain your answer...[1] 1 ...................... The diagram shows the chromatogram obtained when four samples of amino acids were analysed.......Classified Chemistry IGCSE 8 Paper_6_Topic 1 (8) June 2007 Q (3) 3 Chromatography can be used to identify amino acids from a sample of protein...... The paper was sprayed with ninhydrin.............. two spots present Explanation …………………………………………………………………………… [2] (d) Suggest why it is necessary to spray the chromatogram with ninhydrin......................... to show the position of the acid (spots) .[1] (b) Which amino acids could possibly be the same? 1 and 3 ...... Sample 4 Sample ……………………………………………………………………………….............................................................................................................................................................................................. (a) Why is the origin line drawn in pencil? Because it does not dissolve in water ..................... c) 1 A solution of copper sulphate was made by reacting excess copper oxide with dilute sulfuric acid.Experimental technique Mostafa Barakat (0100 165 44 62) .p 100°C)? fraction distillation ………………………………………………………………………………………………[2] 1 . spatula measuring cylinder tripod (a) Complete the empty boxes to name the pieces of apparatus.p 78°C) and water (b. The diagram shows the method used.Classified Chemistry IGCSE Paper_6_Topic 1 9 (9) June 2008 Q (1_a. (c) Draw a labelled diagram to show how the mixture was filtered [3] [2] (10) June 2008 Q (7_b) 7 This label is from a container of ‘Bite Relief’ solution (b) What practical method could be used to separate the mixture of alcohol (b. ............................................................. b................................................................................. ii) 1 A student reacted nitric acid with magnesium oxide to prepare magnesium nitrate......[1] (12) June 2009 Q (6_a) 6 Acid base indicators Indicators are used to identify acids and bases.............. ........................................................................ Indicators can be obtained from berries and other fruits............................................................................................................................................... ...........[3] 1 .........Classified Chemistry IGCSE Paper_6_Topic 1 10 (11) June 2009 Q (1_a.............................................................................. 1) Add water .......................................................... [3] (b) (ii) What method is used to remove the unreacted magnesium oxide after stage 3? Filteration ................................................................................................... (a) Plan an experiment to obtain an aqueous solution of an indicator from some berries.............Experimental technique Mostafa Barakat (0100 165 44 62) ........ 2) Crush berries ................................................................................................................. stirrer beaker balance (a) Complete the boxes to identify the pieces of apparatus labelled............................................................ The diagram shows the procedure followed in three stages............................................................................................................................. 3) Heat ... 4) Filter ............................. ........... .................. [1] (14) June 2010 (62) Q (1_a......... gas should be collected downwards .............. [3] (b) Identify one mistake in the diagram... G and H.............................. used to separate three different mixtures....... F....... b) 1 The diagram shows the apparatus used to prepare a gas.. separating funnel gas jar flask (a) Complete the boxes to name the apparatus.... c) 1 The diagrams show three sets of apparatus. 1 ........ The gas is more dense than air....Classified Chemistry IGCSE Paper_6_Topic 1 11 (13) June 2010 (61) Q (1_a....... b....Experimental technique [3] Mostafa Barakat (0100 165 44 62) ........ Bunsen burner condenser tripod (a) Complete the boxes to name the apparatus used....... ........................................................................................................................................................... The student followed these instructions.Experimental technique Mostafa Barakat (0100 165 44 62) ....................................................................... 4) spots at different levels ................................... 2 Decant the liquid................................................................................................ Pestle and mortar ............ 1 Cut the grass into small pieces and crush the grass by grinding with sand and ethanol.................... ........................................ [4] 1 ............................................................................. 1) chromatogram paper .............................................................................. pour liquid off ................................. 3 Investigate which colours are present in the green solution...................... 3) use water as solvent ................. You may draw a diagram to help you answer this question.................................................. [1] (ii) Which apparatus is used to separate a mixture of coloured dyes? G .................... [1] (c) Outline how the student could carry out instruction 3...... 2) apply solution to paper ...................................................................................................................................................................................................................................................................................................... .................................. [1] (b) Explain the term decant......................................................................................... [1] (15) June 2010 [62] (Q 2) 2 A student investigated the green colour in grass....Classified Chemistry IGCSE 12 Paper_6_Topic 1 (b) (i) Which apparatus is used to obtain crystals of a salt from a solution of the salt? F .................... (a) Name the apparatus used to crush the grass in instruction 1......................................................... ..................................... ZnSO 4.. 3) 1 A student heated hydrated zinc sulfate crystals...................................................... [1] 1 .........7H2O.................................................... water ..................Classified Chemistry IGCSE 13 Paper_6_Topic 1 (16) June 2011 [61] Q (1............................ Beaker (a) Complete the box to identify the piece of apparatus labelled......................... (ii) where the sample of water would collect...... [1] (b) Name the solvent used.......................... The colours are water-soluble dyes. boiling point test ............. chromatography ....................................................................................... [2] 3 The colours present in some fruit sweets can be separated using the apparatus below.......................... (c) State the purpose of the ice cubes............................................................. (b) Use labelled arrows to indicate: (i) where the heat is applied.......................................... [1] (d) Describe a physical test for pure water.................... 100 C result ........... [1] [2] to cool the water or steam ...........................................Experimental technique Mostafa Barakat (0100 165 44 62) ....... (a) Name the process used to separate the colours....... using the apparatus below to obtain a sample of water........................ .....................................Classified Chemistry IGCSE 14 Paper_6_Topic 1 The results obtained for the colours in two different sweets............... C and D........ (c) What is the name for the line at position B? Base line .................................................................................................Experimental technique Mostafa Barakat (0100 165 44 62) .... [3] (17) June 2011 [62] Q (1_a........................ b) 1 A student separated an aqueous solution of sodium chloride...................................................................................................... [1] 1 ............................... [1] (d) What conclusions can you draw about the colours present in sweets C and D? sweet C has 4 colours ......................... are shown below................................................................ ............................. sweet D has 3 colours .... (a) Which of these pieces of apparatus is most suitable to measure 70 cm 3 of the solution? Tick one box............................. She measured out 70 cm3 of the solution and then obtained pure water from the solution.......................... ............................. ........................................................................................... ............................................................................................................................ B or C......................Experimental technique Mostafa Barakat (0100 165 44 62) .......................................................Classified Chemistry IGCSE 15 Paper_6_Topic 1 (b) (i) Complete the empty boxes to name the pieces of apparatus below condenser evapourating dish tripod (ii) Which method of separation.......... A................................................. heat to crystallizing point until saturated .......... [2] 1 .......................... would be most suitable to obtain pure water from the solution? A Distillation apparatus ............ [1] (c) Describe how crystals of sodium chloride could be quickly obtained from the solution............................................... ........ [2] (b) How could the dissolving process in Stage 2 be speeded up? stir / mix / shake ........................................... The diagram shows the procedure followed in three stages....................... Stage 6 the caffeine crystals were checked for purity..Classified Chemistry IGCSE Paper_6_Topic 1 16 (18) June 2012 [61] Q (1_a............ Caffeine is soluble in water and in trichloromethane... [1] 1 .............................................. 1) evapourating of water 2) crystals formed 3) colour goes brown ......................... Stage 2 Hot water was added to the crushed beans to dissolve the soluble substances..................... (a) What apparatus should be used to crush the beans in Stage 1? pestle and mortar ............Experimental technique Mostafa Barakat (0100 165 44 62) ........ [2] (c) Describe the effect of boiling the solution of iron(II) sulfate for several minutes ............................. Stage 3 the crushed beans were separated from the liquid solution......Stage 5from the caffeine was crystallised from the trichloromethane solution......................... Stage 1 some coffee beans were crushed into small pieces... Stage 4 the liquid was allowed to cool and shaken with trichloromethane to extract the caffeine the water ... an organic solvent........ [3] (19) June 2012 [61] Q (3) (3) Coffee beans contain caffeine and other compounds.............. A student obtained crystals of caffeine by the following method........ spatula tripod (a) Complete the boxes to identify the pieces of apparatus labelled................................................ c) 1 A student reacted excess iron powder with sulfuric acid to prepare a solution of iron(II) sulfate........................... ........................................................................ [2] (e) What method could be used to check the purity of the crystals in Stage 6? melting point / chromatography ........ [1] 1 ......Classified Chemistry IGCSE 17 (c) Draw a diagram of the apparatus used in Stage 3..................... Paper_6_Topic 1 [2] (d) How should Stage 5 be carried out? heat to crystallizing point in fume cupboard ........................................................Experimental technique Mostafa Barakat (0100 165 44 62) .............................................................................. Sodium hydroxide was added to the acid until the solution was neutral.Classified Chemistry IGCSE 18 Paper_6_Topic 1 (20) Nov 2001 Q (1_a) 1 The diagrams show the apparatus used to find the concentration of a nitric acid solution. beaker pipette burette (a) Complete the boxes to name the apparatus used.Experimental technique Mostafa Barakat (0100 165 44 62) . [3] 1 .0 cm3 of nitric acid was added to a flask. The volume of the sodium hydroxide was noted. 25. ............................................ b) 1 A student investigated the neutralization of dilute hydrochloric acid................. (a) Identify the pieces of apparatus labelled: spatula A.... ........................................[3] (b) What does the term excess mean? more than enough ............................................................................Classified Chemistry IGCSE 19 Paper_6_Topic 1 (21) Nov 2002 Q (1_a................................................................................................................[1] 1 ........................................................................................................................................................... funnel C......................................................................Experimental technique Mostafa Barakat (0100 165 44 62) ..................................................... using an excess of calcium carbonate................. beaker B.................... ................. [3] [1] fractional distillation ................................ 4 Boil the mixture with the watch glass covering the beaker................ 2 Crush the sweets.................... 3 Place the crushed sweets in the beaker containing 100 cm 3 of ethanol................................ a beaker......[2] 1 ....... (c) Name this separation process..................Experimental technique Mostafa Barakat (0100 165 44 62) ...... (b) Indicate by an arrow where heat is applied.... a watch glass......... 6 Investigate which colours are present in the orange solution. ........... eye protection and 100 cm 3 of ethanol..................Classified Chemistry IGCSE Paper_6_Topic 1 20 (22) Nov 2003 Q (1) 1 The apparatus below was used to separate ethanol from water.................................... The student followed these instructions: 1 Collect sweets........ condenser fractionating column beaker (a) Complete the empty boxes to name the pieces of apparatus........... (a) Why should the sweets be crushed? larger surface area ......................................... 5 Decant the liquid and concentrate it by evaporation until the colour is dark orange...................................................................................[2] (23) Nov 2003 Q (2) 2 A student extracted and investigated the orange colour in some sweets.... .................................................................................................................................................................................................................. liquid pour off .... to prevent loss of solvent ......................................................... 2) use water as solvent .. 1) apply orange concentrate to the paper ...........................................[1] (e) Explain the term decant..................................... other than carrying out the experiment in a well-ventilated laboratory and using eye protection............................................ 4) results of the experiment ........................... gloves / goggls ....................................................................[1] (d) State the purpose of the watch glass..............................................................[1] (f) Describe how the student could carry out instruction 6.............................................................. You may draw a diagram in the space below to help you answer the question...................................................................................................................................Classified Chemistry IGCSE 21 Paper_6_Topic 1 (b) Why should the experiment be carried out in a well-ventilated laboratory? because ethanol is inflammable substance ...........................................................................[1] (c) State one safety precaution that the student should have taken...............[5] 1 ........... chromatography .................................................................................................................................................................. 3) description of elution ...............Experimental technique Mostafa Barakat (0100 165 44 62) ............................................................................... Classified Chemistry IGCSE 22 Paper_6_Topic 1 (24) Nov 2004 Q (1_a..……………………………………………………………………….. Dilute hydrochloric acid was added to zinc hydrochloric acid zinc (a) Identify the pieces of apparatus labelled measuring cylinder A.[2] (b) Complete the boxes 1 . ………………………………………………………………………………………. flask B. ………….Experimental technique [1] Mostafa Barakat (0100 165 44 62) . b) 1 The apparatus below was used to make hydrogen. ...................................................... 4) check highest / position of spots ............................................... 5) compare to find ink from banknote ..............................Experimental technique Mostafa Barakat (0100 165 44 62) ........ Describe an experiment to show which one of these inks is the same as the ink from the banknote........................................................................................................................................ chromatography ..................................................................................................................... 2) add organic solvent / water ...............................................................................................................Classified Chemistry IGCSE 23 Paper_6_Topic 1 (25) Nov 2004 Q (7) 7 Forged Banknote A fake banknote can be investigated by dissolving the ink off the paper....... ............................................................................[6] 1 ....................................................................................................................................................................................................... You are provided with four different inks from four different criminals................................................ 1) apply inks to the chromatogram paper .................. You can use a labelled diagram to help you answer the question.................. 3) rises up paper . .... filteration ..................... heat to crystallizing point .......................... spatula beaker measuring cylinder (a) Complete the boxes to identify the pieces of apparatus labelled............. ............... The diagram shows the procedure followed................................ (a) What apparatus is used in Step 1? mortar and pastle ..................................................................................................Classified Chemistry IGCSE 24 Paper_6_Topic 1 (26) Nov 2005 Q (1_a.............................................................................................[2] (27) Nov 2005 Q (3_a................................................................. c) 1 A student reacted sulfuric acid with copper(II) oxide..... chlorophyll is more soluble in ethanol .......... Step 2 The grass is ground with ethanol until the solution is saturated.................... [3] (c) Describe how crystals could be quickly obtained from the solution. c) 3 The green pigment chlorophyll can be obtained from grass.........................[1] (c) Name the separation method in Step 3....................[1] 1 ..................................Experimental technique Mostafa Barakat (0100 165 44 62) .........................................[2] (b) Suggest why the grass is ground with ethanol rather than water in Step 2....... Step 3 The solution is separated from the rest of the mixture....................................................................................... Step 4 The colours in the solution are separated. Step 1 The grass is crushed with sand. .......................................... tong beaker watch glass a) Complete the empty boxes to name the pieces of apparatus...................................................................Classified Chemistry IGCSE 25 Paper_6_Topic 1 (d) Describe how Step 4 is carried out.................................... ......................................... 1) add pigments to chromatogram paper ........................................................................................... 2) use water as solvent ...[4] (28) Nov 2006 Q (1_a) 1 The diagram shows the formation of a solution of magnesium hydroxide from magnesium....................................................................................................................................................... ........................................................ chromatography .......................................................... ..............................................................................................................................Experimental technique [3] Mostafa Barakat (0100 165 44 62) ................................................................... 1 ..................... .............................................................................................................. ...............................................................[1] 1 ................................................................................................................................................................................................................. hair dryer / wind / increase temperature .......................................................................................Classified Chemistry IGCSE 26 Paper_6_Topic 1 (29) Nov 2006 Q (6) 6 You are provided with a pot of paint as shown below The paint is a mixture of a liquid and a solid.......................................................................................................................................................................................................... 3) use solvent ................ . (a) How can a sample of the solid be separated from the rest of the paint? 1) plant sample + water .........................................................................................................................[2] (ii) Suggest how you could speed up this drying process....................................[2] (b) How would you determine the number of coloured substances contained in the solid you separated in (a)? 1) solid + organic solvent .................... The solids are insoluble in water but soluble in organic solvents...................... 3) remove the residue ............. 4) description of spots ..........................................Experimental technique Mostafa Barakat (0100 165 44 62) .................... 2) add to chromatogram paper .................................................. start the time ........................................................ The liquid can be dissolved in water.........................................................................................................................[4] (c) The label on the paint tin states “Touch-dry in three hours” (i) How could you check this value? apply points.................................................................................................. 2) filteration ............................................................................................................................................. ..................................... .........Classified Chemistry IGCSE Paper_6_Topic 1 27 (30) Nov 2008 Q (1) 1 The colours present in some blackcurrant sweets can be separated by chromatography. (b) (i) Name the solvent used. in the box...... the origin on the diagram........ [3] The apparatus below was used to carry out the chromatography... The diagrams show how the colours can be extracted from the sweets stirrer funnel mortar (a) Complete the empty boxes to name the pieces of apparatus.... with an arrow....................... o o o ----------------- 1 .[1] (ii) Label................. The colours are water-soluble dyes..........Experimental technique Mostafa Barakat (0100 165 44 62) ... water ................................ the chromatogram you would expect if two different colours were present in the sweets........ [1] (c) Sketch....... .................................................................. Crush some leaves to extract the coloured pigments......................................................................................................... solvent ........ .......................................... 2........................................................[4] 1 ........... (b) Give a test by which you could identify pure water.................................... mortar ....................................................................................................................................................... • pure water................................ Use the liquid extract to find the number of coloured pigments in the leaves.............Experimental technique Mostafa Barakat (0100 165 44 62) ............................................................................................. 1...... 2) use suitable solvent ............................................................................................................................................................................. 100 C Result ……………………………………………………………………………………… [2] (32) Nov 2009 Q (7) 7 Leaves from trees contain a mixture of coloured pigments which are not soluble in water................ A space has been left below if you want to draw a diagram to help answer the question chromatography ................... sand .............................................................................................. • hexene........ (a) What would the student need in order to effectively carry out instruction 1? pestle ..... boiling point Test ……………………………………………………………………………………………..Classified Chemistry IGCSE 28 Paper_6_Topic 1 (31) Nov 2009 Q (3_b) 3 Three unlabelled bottles of chemicals each contained one of the following liquids: • sodium nitrate dissolved in water. ...............................[3] (b) Describe an experiment to carry out instruction 2.................................................. A student was given these two instructions to investigate the pigments in the leaves......................................................................................... 1) applay spot to chromatogram paper ............... ................................. chromatography ................. burette pipette flask (a) Complete the boxes to name the apparatus used.............. Substances C... __ solvent (a) Name this method of separation.................................... E and F are single colours...........Experimental technique Mostafa Barakat (0100 165 44 62) .... Sodium hydroxide solution was added to hydrochloric acid until the solution was neutral................................................ D.Classified Chemistry IGCSE Paper_6_Topic 1 29 (33) Nov 2010 [62] Q (1_a) 1) The diagram shows the apparatus used by a student to find the concentration of hydrochloric acid..... [1] 1 ................ . A and B............................... [3] (34) Nov 2011 [61] Q (3_a) 3 The diagram shows the results of an experiment to separate and identify the colours present in two coloured mixtures...... ....................................... (b) What name is given to the separation method in A? [3] filteration ......................................... ......................................................... [1] 1 ........................................................ [1] (35) Nov 2011 [63] Q (1) 1 Three sets of apparatus.................................................................... A has 3 colours while B has 2 colours difference ............................................... stirrer funnel evapourating dish (a) Complete the empty boxes to name the pieces of apparatus..........................................................................................Classified Chemistry IGCSE Paper_6_Topic 1 30 (b) Draw a line on the diagram to show the level of the solvent at the beginning of the experiment..........................................................................................Experimental technique Mostafa Barakat (0100 165 44 62) .................................................................................... ..... [1] (d) State one difference and one similarity between the coloured mixtures........................................................................................ B and C............................... both contain same colour similarity .......................................................................................... A and B...................................................................... . are shown below....................... A............................. [1] (c) Why should a pencil be used instead of a pen to draw the origin line? because it is insoluble in water ..................................................................... [2] (e) Which substances are present in mixture A? ............................................................. ...................................................................................................... ..................................................... ............................................................. chromatography ..................................................................................................................................................................................................................................................................................................................................................................... [1] (b) What does the hazard sign indicate? flammable .......... .................................................................................. .................................................. [4] 1 .....Experimental technique Mostafa Barakat (0100 165 44 62) .................................................... [1] (d) Describe an experiment to investigate the number of coloured substances present in a sample of the lemon oil obtained from Kleen Air.............................................................................................................................................................................................................................................................................. [1] (36) Nov 2011 [63] Q (6) 6 The label on an aerosol can of Kleen Air air freshener is shown....................................................................................................... (a) What is meant by the term solvent? liquid that dissolve other substances .......................................Classified Chemistry IGCSE 31 Paper_6_Topic 1 (c) Which apparatus would be most suitable to obtain crystals from an aqueous solution of copper sulfate? C ......................................................... ............................... [1] (c) What method could be used to obtain ethanol (boiling point 78 °C) from a mixture of ethanol and propanone (boiling point 56 °C)? fractional distillation .........................................................