IGCSE Chemistry Paper6b 2006

Centre Number Candidate Number Name UNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS International General Certificate of Secondary Education CHEMISTRY 0620/06 Paper 6 Alternative to Practical October/November 2006 1 hour Candidates answer on the Question Paper. No additional materials required. READ THESE INSTRUCTIONS FIRST Write your name, Centre number and candidate number at the top of this page. Write in dark blue or black pen in the spaces provided on the Question Paper. You may use a pencil for any diagrams, graphs or rough working. Do not use staples, paper clips, highlighters, glue or correction fluid. Answer all questions. The number of marks is given in brackets [ ] at the end of each question or part question. For Examiners Use 1 2 3 4 5 6 Total This document consists of 13 printed pages and 3 blank pages. IB06 11_0620_06/4RP  UCLES 2006 [Turn over 2 © UCLES 2006 0620/06/O/N/06 For Examiner's Use 1 The diagram shows the formation of a solution of magnesium hydroxide from magnesium. water magnesium oxide heat indicator turns blue solution of magnesium hydroxide Universal Indicator solution magnesium burning to form magnesium oxide (a) Complete the empty boxes to name the pieces of apparatus. [3] (b) What type of chemical reaction is the burning of magnesium? [1] (c) Suggest a pH for the solution of magnesium hydroxide. [1] 2 The diagram shows the rusting of a sample of iron filings. 150 mm 125 mm air before rusting air after rusting water damp iron filings (a) What colour are the rusty filings? [1] (b) Why does the water rise up the tube after rusting? [1] 3 © UCLES 2006 0620/06/O/N/06 [Turn over For Examiner's Use (c) Calculate the percentage of air used in the rusting of the iron. [2] (d) How would the results differ if pure oxygen was in the tube instead of air before rusting? [1] 4 © UCLES 2006 0620/06/O/N/06 For Examiner's Use 3 An investigation into the reaction of calcium with water was carried out using the apparatus below. The temperature of the water increased during the experiment. 20 40 60 80 100 cm3 reaction mixture The volume of hydrogen collected at one minute intervals was measured. Use the diagrams to record the volumes in the table. 10 20 30 40 50 60 70 80 90 time /minutes 0123456 syringe diagram volume of gas /cm3 10 20 30 40 50 60 70 80 90 10 20 30 40 50 60 70 80 90 10 20 30 40 50 60 70 80 90 10 20 30 40 50 60 70 80 90 10 20 30 40 50 60 70 80 90 10 20 30 40 50 60 70 80 90 [2] 5 © UCLES 2006 0620/06/O/N/06 [Turn over For Examiner's Use (a) Plot the results on the grid. Join all of the results with a smooth curve. 0 1 2 3 4 5 6 volume of gas /cm3 100 80 60 40 200 time /minutes [3] (b) What type of chemical reaction occurs when calcium reacts with cold water? [1] (c) (i) Use the graph to describe how the speed of this reaction changes during the six minutes. [2] (ii) Explain possible reasons for the changes in (c)(i). [2] 6 © UCLES 2006 0620/06/O/N/06 For Examiner's Use 4 An investigation was carried out into the reactions of aqueous copper(II) sulphate with magnesium, iron and zinc. Experiment 1 By using a measuring cylinder, 5 cm3 of aqueous copper(II) sulphate was added to each of three test-tubes. The initial temperature of the solution was measured. Zinc powder was added to the first test-tube, iron powder to the second tube and magnesium powder to the third tube. The mixtures were stirred with the thermometer. All the observations were recorded and the maximum temperature reached measured. (a) Use the thermometer diagrams to complete the results table. Table of results metal added temperature of solution /oC observations moderate effervescence, solution paler, brown solid. little effervescence, brown solid. rapid effervescence, pops with lighted splint, brown solid. temperature difference /oC zinc iron magnesium initial maximum 30 25 20 60 55 50 30 25 20 75 70 65 30 25 20 45 40 35 ........ ........ ........ ........ ........ ........ [4] (b) Use your results and observations to answer the following questions. (i) Which metal is most reactive with aqueous copper(II) sulphate? [1] (ii) Give two reasons why you chose this metal. 1 2 [2] (iii) Identify the gas given off when magnesium reacts with aqueous copper(II) sulphate. [1] 7 © UCLES 2006 0620/06/O/N/06 [Turn over For Examiner's Use (c) The reactions of magnesium and zinc with aqueous copper(II) sulphate were investigated in more detail. Experiment 2 By using a measuring cylinder 10 cm3 of aqueous copper(II) sulphate was poured into a polystyrene cup. The initial temperature of the solution was measured. A 1 g sample of magnesium powder was added to the cup and the temperature measured every 10 seconds for 1 minute. Use the thermometer diagrams on page 8 to complete the results table. Experiment 3 Experiment 2 was repeated using zinc powder instead of magnesium. Use the thermometer diagrams on page 8 to complete the results table. 8 © UCLES 2006 0620/06/O/N/06 For Examiner's Use Table of results 30 25 20 time /seconds 0 10 20 30 40 50 60 temperature /oC Experiment 2 Experiment 3 30 25 20 65 60 55 70 65 60 35 30 25 40 35 30 75 70 65 70 65 60 45 40 35 50 45 40 70 65 60 30 25 20 60 55 50 35 30 25 ............ ............ ............ ............ ............ ............ ............ ............ ............ ............ ............ ............ ............ ............ [6] 9 © UCLES 2006 0620/06/O/N/06 [Turn over For Examiner's Use (d) Plot the results of both Experiments on the grid below. Draw two smooth line graphs. Clearly label the graphs. 10 20 30 time /seconds temperature /oC 40 50 60 70 60 50 40 30 20 100 [4] (e) Use your graph to estimate the temperature of the reaction mixture in Experiment 2 after 5 seconds. Indicate clearly on the graph how you obtained your answer. [2] (f) Sketch lines on the grid to show the predicted results if Experiment 2 were repeated using: (i) larger pieces of magnesium; (ii) iron powder. Clearly label the lines. [2] 10 © UCLES 2006 0620/06/O/N/06 For Examiner's Use (g) Why is a polystyrene cup used instead of a glass container? [1] (h) Suggest one improvement to the method in Experiment 2. [1] 11 © UCLES 2006 0620/06/O/N/06 [Turn over For Examiner's Use 5 Two solids, F and G, were analysed. Solid F was an ammonium salt and solid G was a potassium salt. The tests on F and G and some of the observations are in the following table. Complete the observations in the table. tests observations Solid F was added to distilled water and shaken to dissolve. The solution was divided into 4 equal portions in test-tubes. colour orange (a) (i) The pH of the first portion of the solution was tested using Universal Indicator solution. pH 5 [2] (ii) Aqueous sodium hydroxide was added to the second portion and heated gently. The gas given off was tested with damp litmus paper. white precipitate (iii) To the third portion of solution, was added dilute nitric acid and then aqueous lead(II) nitrate. (iv) To the fourth portion of solution, was added dilute nitric acid followed by aqueous silver nitrate. white precipitate (b) (i) Solid G was dissolved in distilled water. The solution was divided into two testtubbes bright yellow precipitate (ii) (a)(iii) was repeated using the first portion of the solution. (iii) (a)(iv) was repeated using the second portion of the solution. pale yellow precipitate 12 © UCLES 2006 0620/06/O/N/06 For Examiner's Use (c) What conclusion can be drawn from test (a)(i)? [2] (d) Name the gas given off in (a)(ii). [1] (e) Identify solid F. [1] (f) Identify solid G. [1] 13 © UCLES 2006 0620/06/O/N/06 For Examiner's Use 6 You are provided with a pot of paint as shown below. coloured solids liquid magnified view of paint The paint is a mixture of a liquid and a solid. The liquid can be dissolved in water. The solids are insoluble in water but soluble in organic solvents. (a) How can a sample of the solid be separated from the rest of the paint? [2] (b) How would you determine the number of coloured substances contained in the solid you separated in (a)? [4] (c) The label on the paint tin states “Touch-dry in three hours” (i) How could you check this value? [2] (ii) Suggest how you could speed up this drying process. [1] 14 0620/06/O/N/06 BLANK PAGE15 0620/06/O/N/06 BLANK PAGE16 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 University of Cambridge Local Examinations Syndicate (UCLES), which is itself a department of the University of Cambridge. 0620/06/O/N/06 BLANK PAGE