Cambridge IGCSE Sciences - Co-ordinated (Double) 0654 — 2009 Oct/Nov Paper 5 · Variant 1

This document consists of 11 printed pages and 1 blank page. IB09 11_0654_05/4RP © UCLES 2009 [Turn over *6272872874* For Examiner's Use 1 2 3 Total UNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS International General Certificate of Secondary Education CO-ORDINATED SCIENCES 0654/05 Paper 5 Practical Test October/November 2009 2 hours Candidates answer on the Question Paper. Additional Materials: As listed in Instructions to Supervisors READ THESE INSTRUCTIONS FIRST Write your Centre number, candidate number and name on all the work you hand in. Write in dark blue or black pen. You may use a pencil for any diagrams, graphs or rough working. Do not use staples, paper clips, highlighters, glue or correction fluid. DO NOT WRITE IN ANY BARCODES. Answer all questions. Chemistry practical notes for this paper are printed on page 12. At the end of the examination, fasten all your work including ray diagrams in Question 2 securely together. The number of marks is given in brackets [ ] at the end of each question or part question. www.XtremePapers.com

3 © UCLES 2009 0654/05/O/N/09 [Turn over For Examiner's Use 1 You are supplied with tubes A, B and C set up as shown in Fig.1.1. The experiment is used to study the conditions needed for photosynthesis. A plant was left in the dark for 48 hours to remove starch. Three leaves were removed and placed in the tubes A, B and C. The tubes were left in daylight for 24 hours. light and carbon dioxide present tube A water light present no carbon dioxide tube B sodium hydroxide solution no light carbon dioxide present tube C water leaf pin lightproof cover Fig. 1.1 (a) Carefully remove the bungs from each tube and put the leaves on a white tile. In Fig. 1.2 draw the leaves to show the patterns of chlorophyll. Label the chlorophyll in one of the diagrams. leaf A leaf B leaf C Fig.1.2 [2]

4 © UCLES 2009 0654/05/O/N/09 For Examiner's Use (b) You are going to do a starch test on the three leaves to find where photosynthesis has taken place. Follow the procedure below. If you wish, you may test all three leaves at the same time. Throughout the experiment remember which leaf is which. • Half fill a beaker with water and bring it to the boil. (You may have a water bath instead). • Using tweezers put the leaf from tube A into the boiling water for one minute. • Take the leaf out of the water. Turn off your Bunsen burner or other naked flame if you have used one. This is important for safety. • Place the leaf into a clean test-tube and add enough alcohol to cover the leaf. Place the tube into your beaker or water bath of hot water for five minutes. The alcohol may boil while it is dissolving the chlorophyll. • Carefully remove the tube from the water, pour off the alcohol into the container provided, then rinse the leaf in cold water. • Spread the leaf out on a white tile and cover it with iodine solution. • Allow the colour to develop for a few minutes. • Repeat this procedure for leaves B and C. (c) After testing with iodine draw diagrams in Fig. 1.3 of the three leaves. Use a pencil to shade where starch is present. Add the label starch. leaf A leaf B leaf C [3] Fig. 1.3 (d) Explain the results of the starch test in terms of the conditions needed for photosynthesis. tube A

5 © UCLES 2009 0654/05/O/N/09 [Turn over For Examiner's Use tube B tube C [4] (e) Why was sodium hydroxide solution placed in tube B? [1] (f) (i) Why did you boil the leaves at the start of the starch test? [1] (ii) Why was water placed in tubes A and C? [1] (g) Describe another experiment to show that light is necessary for starch production if the leaves remain on the plant. You may draw a diagram to help your answer. [3]

6 © UCLES 2009 0654/05/O/N/09 For Examiner's Use 2 Carry out the following experiment to plot the path of a ray of light through a rectangular block. (a) Record the value provided of the refractive index of the block. refractive index = [1] (b) Place the block on a sheet of paper and draw a pencil line around it. Remove the block. Draw a normal to the top line, about a third of the way along from the left hand side. Using a protractor, draw a line at 30° to the block, making an angle of incidence, i, of 60°. Place two pins, P1 and P2, on this line as shown in Fig. 2.1. Fig. 2.1 P1 P2 30° i normal Replace the block in its original position inside the pencil lines already drawn. Look through the edge of the block from the other side so that images of these first two pins can be seen. Move your head until P2 is in line with P1. Place two more pins into the paper in line with the images. Label these positions P3 and P4. Remove the block and pins and complete the diagram as shown in Fig. 2.2. Fig. 2.2 P1 P2 P3 P4 30° i r normal Measure the angle of incidence, i, and the angle of refraction, r. Record these in Fig. 2.3. (c) Repeat using an angle of 35° to the block, making an angle of incidence, i, of 55°. Measure and record the angles of incidence and refraction in Fig. 2.3. Use a fresh sheet of paper if necessary.

7 © UCLES 2009 0654/05/O/N/09 [Turn over For Examiner's Use (d) Make three further sets of measurements using angles of 50°, 60° and 70° to the block, producing angles of incidence, i, 40°, 30° and 20°. Use a fresh sheet of paper if necessary. Measure and record the angles of incidence and refraction in Fig. 2.3. angle of incidence i angle of refraction r Fig. 2.3 [5] Attach your ray diagrams to your paper at the end of the examination. (e) Plot a graph of angle of incidence (vertical axis), against angle of refraction (horizontal axis). Draw a smooth curve through your points. angle of incidence i angle of refraction r [3]

8 © UCLES 2009 0654/05/O/N/09 For Examiner's Use (f) Read off the angle of incidence for an angle of refraction of 25°. Record this in the space below. angle of incidence = [1] (g) The refractive index of the glass is given by sine (angle of incidence) sine (angle of refraction) Use the table of sines of angles, Fig. 2.4 to find this ratio for the angles in (f). If necessary, estimate the value of sine i from Fig. 2.4. sine of angle of incidence recorded in (f) = sine of angle of refraction 25° = Calculate the refractive index of the block. refractive index = [2] angle / ° sine of angle 25 0.423 30 0.500 35 0.574 40 0.643 45 0.707 50 0.766 55 0.819 Fig. 2.4 (h) Does your result for the refractive index agree with that given and recorded in (a)? Comment on your answer. [1]

9 © UCLES 2009 0654/05/O/N/09 [Turn over For Examiner's Use (i) How would the angles of refraction, recorded in Fig. 2.3, differ for a block of different refractive index? Explain your answer. [2]

10 © UCLES 2009 0654/05/O/N/09 For Examiner's Use 3 You are provided with three solutions, A, B and C, of potassium manganate(VII) each with a different concentration. You will use solution X to determine the most concentrated solution, A, B or C. (a) Using the dropping pipette and no other apparatus, produce drops of water and estimate the volume of one drop. estimated volume of one drop = cm3 [1] (b) Using the small measuring cylinder, place 3 cm3 of solution A into a test-tube. Add a few drops of dilute sulfuric acid. Using the dropping pipette, add solution X a drop at a time, counting the drops until the solution turns colourless. Record the number of drops in the table below. (c) (i) Repeat test (b) using solution B. (ii) Repeat again using solution C. This time, keep the colourless solution for use in (e). solution number of drops A B C [4] (d) Which is the most concentrated solution, A, B or C? Explain your answer. most concentrated solution is explanation [2] (e) To the colourless solution from test (c)(ii), add sodium hydroxide solution until no further change occurs. Record your observation below. observation = [1] (f) Carry out the following tests on solution X. Record your observations. (i) Place about 2 cm3 of solution X in a test-tube. Add a few drops of hydrochloric acid followed by drops of barium chloride solution. observation = [1]

11 © UCLES 2009 0654/05/O/N/09 [Turn over For Examiner's Use (ii) Place about 2 cm3 of solution X in a test-tube. Add a few drops of nitric acid followed by drops of silver nitrate solution. observation = [1] (iii) Place about 2 cm3 of solution X in a test-tube. Add sodium hydroxide solution until no further change occurs. observation = [1] (g) Name solution X. [2] (h) In test (a) you estimated the volume of a drop from the dropping pipette. Describe how you could more accurately find the volume of one drop. [2]

12 Permission to reproduce items where third-party owned material protected by copyright is included has been sought and cleared where possible. Every reasonable effort has been made by the publisher (UCLES) to trace copyright holders, but if any items requiring clearance have unwittingly been included, the publisher will be pleased to make amends at the earliest possible opportunity. University of Cambridge International Examinations is part of the Cambridge Assessment Group. Cambridge Assessment is the brand name of University of Cambridge Local Examinations Syndicate (UCLES), which is itself a department of the University of Cambridge. © UCLES 2009 0654/05/O/N/09 CHEMISTRY PRACTICAL NOTES Test for anions anion test test result carbonate (CO3 2-) add dilute acid effervescence, carbon dioxide produced chloride (Cl-) [in solution] acidify with dilute nitric acid, then add aqueous silver nitrate white ppt. nitrate (NO3 -) [in solution] add aqueous sodium hydroxide then aluminium foil; warm carefully ammonia produced sulfate (SO4 2-) [in solution] acidify then add aqueous barium chloride or aqueous barium nitrate white ppt. Test for aqueous cations cation effect of aqueous sodium hydroxide effect of aqueous ammonia ammonium (NH4 +) ammonia produced on warming - copper(II) (Cu2+) light blue ppt., insoluble in excess light blue ppt., soluble in excess giving a dark blue solution iron(II) (Fe2+) green ppt., insoluble in excess green ppt., insoluble in excess iron(III) (Fe3+) red-brown ppt., insoluble in excess red-brown ppt., insoluble in excess zinc (Zn2+) white ppt., soluble in excess giving a colourless solution white ppt., soluble in excess giving a colourless solution Test for gases gas test and test results ammonia (NH3) turns damp red litmus paper blue carbon dioxide (CO2) turns limewater milky chlorine (Cl2) bleaches damp litmus paper hydrogen (H2) “pops” with a lighted splint oxygen (O2) relights a glowing splint

UNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS International General Certificate of Secondary Education MARK SCHEME for the October/November 2009 question paper for the guidance of teachers 0654 CO-ORDINATED SCIENCES 0654/05 Paper 5 (Practical Test), maximum raw mark 45 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 must be read in conjunction with the question papers and the report on the examination. • CIE will not enter into discussions or correspondence in connection with these mark schemes. CIE is publishing the mark schemes for the October/November 2009 question papers for most IGCSE, GCE Advanced Level and Advanced Subsidiary Level syllabuses and some Ordinary Level syllabuses. www.XtremePapers.com

Page 2 Mark Scheme: Teachers’ version Syllabus Paper IGCSE – October/November 2009 0654 05 © UCLES 2009 1 (a) good quality of drawings ; chlorophyll label ; [2] (c) leaf B and C same shape as in part (a) ; leaf A only one containing starch, correctly labelled ; ignore small traces of starch in B and C pattern of starch matches chlorophyll pattern in (a) ; [3] (d) (leaf A starch present) light and carbon dioxide both needed (for photosynthesis) ; starch only found where chlorophyll is ; leaf B no photosynthesis because carbon dioxide is absent ; do not allow if stated that water also absent leaf C no photosynthesis because light is absent ; [4] (e) to remove carbon dioxide ; OWTTE [1] (f) (i) to soften the cuticle / kill leaf / allow entry of ethanol ; [1] (ii) as a control ; [1] (g) destarch the plant ; put lightproof paper over leaf ; leave for 24 hours in light ; do starch test ; [3 max] [Total: 15]

Page 3 Mark Scheme: Teachers’ version Syllabus Paper IGCSE – October/November 2009 0654 05 © UCLES 2009 2 (a) recording the refractive index ; [1] (d) 5 suitable drawings ;; Give ONE mark if only 4 (2) Table angles of i are about 60°, 55°, 40°, 30° and 20° and r values ;; ONE mark if only 4 values (2) angles of r decrease appropriately ; (1) [5] (e) Graph scale ; plotting ; suitable curve ; [3] (f) correctly read from graph ; [1] (g) both sines correct, estimating if necessary ;; if clearly not from the table provided do not allow ratio correctly calculated [2] (h) suitable comment ; looking for some idea of accuracy of experiment [1] (i) if the refractive index is greater, then angles of refraction would be smaller ; or vice versa the denser the medium, the greater the ray is bent ; [2] [Total: 15]

Page 4 Mark Scheme: Teachers’ version Syllabus Paper IGCSE – October/November 2009 0654 05 © UCLES 2009 3 (a) accept anything between 0.03 and 0.08 ; [1] (c) results for all three ; value for B is half A within 2 drops ; value for C is half B within 2 drops ; value for C within 2 drops of SV ; if A is larger than 20, 2 drops becomes 3 drops [4] (d) most concentrated is A ; needs the largest number of drops ; [2] (e) brown ppt. ; [1] (f) (i) white ppt. ; [1] (ii) dirty white, grey or cloudy (ppt. not necessary here as reaction is slow) ; [1] (iii) green ppt. ; [1] (g) one mark for iron(II) and one for sulfate ;; [2] (h) count drops into a measuring cylinder to suitable volume (at least 5 cm3) ; divide by number of drops ; [2] [Total: 15]