Cambridge IGCSE Chemistry (BES) 0439 — 2017 Oct/Nov Paper 4 · Variant 1

READ THESE INSTRUCTIONS FIRST Write your Center number, candidate number and name on all the work you hand in. Write in dark blue or black pen. You may use an HB pencil for any diagrams or graphs. Do not use staples, paper clips, glue or correction fluid. DO NOT WRITE IN ANY BARCODES. Answer all questions. Electronic calculators may be used. A copy of the Periodic Table is printed on page 16. You may lose marks if you do not show your working or if you do not use appropriate units. At the end of the examination, fasten all your work securely together. The number of marks is given in brackets [ ] at the end of each question or part question. CHEMISTRY (US) 0439/41 Paper 4 Theory (Extended) October/November 2017 1 hour 15 minutes Candidates answer on the Question Paper. No Additional Materials are required. Cambridge International Examinations Cambridge International General Certificate of Secondary Education This document consists of 16 printed pages. [Turn over IB17 11_0439_41/FP © UCLES 2017 *5029656495*

2 0439/41/O/N/17 © UCLES 2017 1 The table gives information about five particles. The particles are all atoms or ions. particle number of protons number of neutrons number of electrons A 6 8 6 B 12 12 12 C 13 14 10 D 8 8 10 E 11 12 11 Answer the following questions using the information in the table. Each particle may be used once, more than once or not at all. (a) Which particle, A, B, C, D or E, (i) is an atom with atomic number 12, … [1] (ii) is an atom with nucleon number 14, … [1] (iii) is an ion with a positive charge, … [1] (iv) has only one electron in its outer shell? … [1] (b) D is an ion of an element. Identify the element and write the formula of D. … [2] [Total: 6]

3 0439/41/O/N/17 © UCLES 2017 [Turn over 2 The graph shows how the temperature of a substance changes as it is cooled over a period of 30 minutes. The substance is a gas at the start. 0 10 20 30 300 250 200 150 100 50 0 temperature / °C time / minutes S T W X Y Z V Each letter on the graph may be used once, more than once or not at all. (a) Which letter, S, T, V, W, X, Y or Z, shows when (i) the particles in the substance have the most kinetic energy, … [1] (ii) the particles in the substance are furthest apart, … [1] (iii) the substance exists as both a gas and a liquid? … [1] (b) Use the graph to estimate the freezing point of the substance.  … °C [1] (c) Name the change of state directly from a solid to a gas. … [1] (d) When smoke is viewed through a microscope, the smoke particles in the air appear to jump around. (i) What term describes this movement of the smoke particles? … [1] (ii) Explain why the smoke particles move in this way. … … … [2] [Total: 8]

4 0439/41/O/N/17 © UCLES 2017 3 (a) When magnesium is added to aqueous copper(II) sulfate a reaction occurs. The ionic equation for the reaction is shown. Mg + Cu2+ Mg2+ + Cu (i) Give one change you would observe during this reaction. … [1] (ii) Explain why this is a redox reaction. … … [1] (iii) Identify the oxidizing agent in this reaction. Give a reason for your answer. … … [2] (iv) A redox reaction occurs when magnesium is heated with iron(III) oxide. Write a chemical equation for the reaction between magnesium and iron(III) oxide. … [2] (b) The metal iron and the alloy steel are commonly used materials. A problem with them is that they rust. (i) How does painting iron and steel prevent rusting? … … [1] (ii) Magnesium blocks can be attached to the bottom of steel boats. Explain how the magnesium blocks prevent the whole of the bottom of the boat from rusting. … … … … [2]

5 0439/41/O/N/17 © UCLES 2017 [Turn over (iii) Replacing the magnesium blocks with copper blocks does not prevent rusting. Explain why the copper blocks do not prevent rusting. … … [1] [Total: 10]

6 0439/41/O/N/17 © UCLES 2017 4 (a) Ethanol, C2H5OH, can be made by fermentation. (i) Complete the chemical equation for the formation of ethanol by fermentation. C6H12O6 …C2H5OH + … [2] (ii) State two conditions required for fermentation. 1 … 2 … [2] (b) Ethanol can also be made by the catalytic hydration of ethene. The equation for the reaction is shown. C2H4 + H2O C2H5OH (i) Name a suitable catalyst for this reaction. … [1] (ii) Calculate the maximum mass of ethanol that can be made from 56 g of ethene. maximum mass of ethanol = … g [2] (c) Ethanol can be oxidized to form ethanoic acid. (i) Name a suitable oxidizing agent for this reaction. … [1]

7 0439/41/O/N/17 © UCLES 2017 [Turn over (ii) A molecule of ethanoic acid has the structure shown. C C O O H H H H Complete the dot-and-cross diagram to show the electron arrangement in ethanoic acid. Show outer shell electrons only. H C H C O O H H [3] (d) Ethanoic acid is a weak acid. (i) When referring to an acid, what is meant by the term weak? … … [1] (ii) Describe how you could show that ethanoic acid is a weaker acid than hydrochloric acid. … … … … [3]

8 0439/41/O/N/17 © UCLES 2017 (e) Carboxylic acids react with alcohols to make esters. The structure of an ester is shown. C C O O C H H H H H C C C H H H H H H H C H H Draw the structures of the carboxylic acid and alcohol from which this ester can be made. Give the names of the carboxylic acid and alcohol. structure of the carboxylic acid name of the carboxylic acid … structure of the alcohol name of the alcohol … [4] [Total: 19]

9 0439/41/O/N/17 © UCLES 2017 [Turn over 5 (a) Solid copper(II) carbonate undergoes thermal decomposition. One of the products of the thermal decomposition is copper(II) oxide. (i) State the color change of the solid seen during the reaction. start color … end color … [1] (ii) Write a chemical equation for the thermal decomposition of copper(II) carbonate. … [1] (b) Copper(II) carbonate reacts with dilute nitric acid. One of the products of the reaction is a solution of copper(II) nitrate. (i) Describe tests for copper(II) ions and nitrate ions. Include the results of the tests. copper(II) ions … … … nitrate ions… … … [4] (ii) Copper(II) nitrate undergoes thermal decomposition. Balance the chemical equation for the thermal decomposition of copper(II) nitrate. …Cu(NO3)2 …CuO + …NO2 + …O2 [1]

10 0439/41/O/N/17 © UCLES 2017 (c) Nitrogen dioxide, NO2, exists in equilibrium with dinitrogen tetroxide, N2O4. Nitrogen dioxide is brown and dinitrogen tetroxide is colorless. 2NO2(g) N2O4(g) brown colorless (i) A sample of nitrogen dioxide and dinitrogen tetroxide at equilibrium was placed in a closed gas syringe. The syringe plunger was pushed in. This increased the pressure in the gas syringe. The temperature was kept constant. nitrogen dioxide and dinitrogen tetroxide at equilibrium end blocked gas syringe State how the color of the gas in the syringe changed. Explain your answer in terms of the position of the equilibrium. … … … … [3] (ii) A sealed tube containing nitrogen dioxide and dinitrogen tetroxide at equilibrium was cooled in an ice bath at constant pressure. The contents of the tube became paler. Suggest an explanation for this observation in terms of the position of the equilibrium. … … … [2] [Total: 12]

11 0439/41/O/N/17 © UCLES 2017 [Turn over 6 Aluminum is extracted from aluminum oxide by electrolysis. (a) Why is aluminum not extracted by heating aluminum oxide with carbon? … … [1] (b) Aluminum oxide is an ionic compound with a high melting point. (i) Complete the dot-and-cross diagram to show the electron arrangement in one of the oxide ions present in aluminum oxide. Include the charge on the oxide ion. One of the aluminum ions is shown. Al O 3+ … [2] (ii) The melting point of aluminum oxide is above 2000 °C. Explain why aluminum oxide has a high melting point. … … … [2]

12 0439/41/O/N/17 © UCLES 2017 (c) Aluminum can be extracted by electrolysis using the apparatus shown. molten aluminum aluminum oxide and cryolite cathode wires anodes + + power supply – + (i) Name the type of particle responsible for the transfer of charge in the wires, … the electrolyte. … [2] (ii) Give two reasons why cryolite is used. 1 … 2 … [2] (iii) Write the ionic half-equation for the formation of aluminum during the electrolysis. … [1] (iv) Explain how carbon dioxide gas is formed at the anodes. … … … [3] (d) When a piece of aluminum is placed in dilute hydrochloric acid, there is no immediate visible reaction. If the aluminum is left in the dilute hydrochloric acid for several hours, bubbles start to form. Explain why aluminum does not react immediately with dilute hydrochloric acid. … … [1] [Total: 14]

13 0439/41/O/N/17 © UCLES 2017 [Turn over Question 7 starts on the next page.

14 0439/41/O/N/17 © UCLES 2017 7 Copper(II) oxide reacts with dilute hydrochloric acid. CuO(s) + 2HCl (aq) CuCl 2(aq) + H2O(l) 6.00 g of copper(II) oxide were added to 50.0 cm3 of 1.00 mol / dm3 hydrochloric acid. This was an excess of copper(II) oxide. (a) The rate of the reaction can be increased by increasing the concentration of the hydrochloric acid or by heating it. (i) In terms of collisions, explain why increasing the concentration of the hydrochloric acid increases the rate of the reaction. … … … … [2] (ii) In terms of collisions, explain why heating the hydrochloric acid increases the rate of the reaction. … … … … [2]

15 0439/41/O/N/17 © UCLES 2017 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. To avoid the issue of disclosure of answer-related information to candidates, all copyright acknowledgements are reproduced online in the Cambridge International Examinations Copyright Acknowledgements Booklet. This is produced for each series of examinations and is freely available to download at www.cie.org.uk after the live examination series. 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. (b) (i) Calculate the number of moles of copper(II) oxide added to the hydrochloric acid. moles of copper(II) oxide = … mol [2] (ii) Calculate the number of moles of hydrochloric acid used. moles of hydrochloric acid = … mol [1] (iii) Calculate the mass of copper(II) oxide that did not react. mass of copper(II) oxide that did not react = … g [2] (c) Crystals of hydrated copper(II) chloride were obtained from the solution at the end of the reaction. The crystals had the following composition by mass: Cl, 41.52%; Cu, 37.43%; H, 2.34%; O, 18.71%. Calculate the empirical formula of the crystals. empirical formula = … [2] [Total: 11]

16 0439/41/O/N/17 © UCLES 2017 Group The Periodic Table of Elements 1 H hydrogen 1 2 He helium 4 I II III IV V VI VII VIII 3 Li lithium 7 4 Be beryllium 9 atomic number atomic symbol Key name relative atomic mass 11 Na sodium 23 12 Mg magnesium 24 19 K potassium 39 20 Ca calcium 40 37 Rb rubidium 85 38 Sr strontium 88 55 Cs cesium 133 56 Ba barium 137 87 Fr francium – 88 Ra radium – 5 B boron 11 13 Al aluminum 27 31 Ga gallium 70 49 In indium 115 81 Tl thallium 204 6 C carbon 12 14 Si silicon 28 32 Ge germanium 73 50 Sn tin 119 82 Pb lead 207 22 Ti titanium 48 40 Zr zirconium 91 72 Hf hafnium 178 104 Rf rutherfordium – 23 V vanadium 51 41 Nb niobium 93 73 Ta tantalum 181 105 Db dubnium – 24 Cr chromium 52 42 Mo molybdenum 96 74 W tungsten 184 106 Sg seaborgium – 25 Mn manganese 55 43 Tc technetium – 75 Re rhenium 186 107 Bh bohrium – 26 Fe iron 56 44 Ru ruthenium 101 76 Os osmium 190 108 Hs hassium – 27 Co cobalt 59 45 Rh rhodium 103 77 Ir iridium 192 109 Mt meitnerium – 28 Ni nickel 59 46 Pd palladium 106 78 Pt platinum 195 110 Ds darmstadtium – 29 Cu copper 64 47 Ag silver 108 79 Au gold 197 111 Rg roentgenium – 30 Zn zinc 65 48 Cd cadmium 112 80 Hg mercury 201 112 Cn copernicium – 114 Fl flerovium – 116 Lv livermorium – 7 N nitrogen 14 15 P phosphorus 31 33 As arsenic 75 51 Sb antimony 122 83 Bi bismuth 209 8 O oxygen 16 16 S sulfur 32 34 Se selenium 79 52 Te tellurium 128 84 Po polonium – 9 F fluorine 19 17 Cl chlorine 35.5 35 Br bromine 80 53 I iodine 127 85 At astatine – 10 Ne neon 20 18 Ar argon 40 36 Kr krypton 84 54 Xe xenon 131 86 Rn radon – 21 Sc scandium 45 39 Y yttrium 89 57–71 lanthanoids 89–103 actinoids 57 La lanthanum 139 89 Ac lanthanoids actinoids The volume of one mole of any gas is 24 dm3 at room temperature and pressure (r.t.p.) actinium – 58 Ce cerium 140 90 Th thorium 232 59 Pr praseodymium 141 91 Pa protactinium 231 60 Nd neodymium 144 92 U uranium 238 61 Pm promethium – 93 Np neptunium – 62 Sm samarium 150 94 Pu plutonium – 63 Eu europium 152 95 Am americium – 64 Gd gadolinium 157 96 Cm curium – 65 Tb terbium 159 97 Bk berkelium – 66 Dy dysprosium 163 98 Cf californium – 67 Ho holmium 165 99 Es einsteinium – 68 Er erbium 167 100 Fm fermium – 69 Tm thulium 169 101 Md mendelevium – 70 Yb ytterbium 173 102 No nobelium – 71 Lu lutetium 175 103 Lr lawrencium –

® IGCSE is a registered trademark. This document consists of 8 printed pages. © UCLES 2017 [Turn over Cambridge Assessment International Education Cambridge International General Certificate of Secondary Education CHEMISTRY (US) 0439/41 Paper 4 Extended Theory October/November 2017 MARK SCHEME Maximum Mark: 80 Published 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 should be read in conjunction with the question paper and the Principal Examiner Report for Teachers. Cambridge International will not enter into discussions about these mark schemes. Cambridge International is publishing the mark schemes for the October/November 2017 series for most Cambridge IGCSE®, Cambridge International A and AS Level components and some Cambridge O Level components.

0439/41 Cambridge IGCSE – Mark Scheme PUBLISHED October/November 2017 © UCLES 2017 Page 2 of 8 Question Answer Marks 1(a)(i) B 1 1(a)(ii) A 1 1(a)(iii) C 1 1(a)(iv) E 1 1(b) O2– M1 O M2 2– 2 Question Answer Marks 2(a)(i) S 1 2(a)(ii) S 1 2(a)(iii) V 1 2(b) any value in the range 130–145 °C 1 2(c) sublimation 1 2(d)(i) Brownian motion 1 2(d)(ii) nitrogen / oxygen / carbon dioxide / air molecules hit / bombard the smoke particles 1 (the bombarding particles) move randomly 1

0439/41 Cambridge IGCSE – Mark Scheme PUBLISHED October/November 2017 © UCLES 2017 Page 3 of 8 Question Answer Marks 3(a)(i) brown / orange solid (forms / is made) OR solution becomes paler / colourless 1 3(a)(ii) magnesium is oxidised AND copper ions are reduced OR magnesium loses electrons AND copper ions gain electrons OR magnesium increases in oxidation number AND copper decreases in oxidation number 1 3(a)(iii) Cu2+ OR copper(II) ions OR copper ions 1 gains electrons 1 3(a)(iv) 3Mg + Fe2O3 → 3MgO + 2Fe M1 Fe2O3 AND MgO M2 fully correct 2 3(b)(i) prevents air / oxygen AND water from reaching the steel 1 3(b)(ii) magnesium is more reactive than iron / steel 1 the magnesium corrodes (before the iron / steel) OR the magnesium corrodes preferentially 1 3(b)(iii) copper is less reactive than iron / steel 1

0439/41 Cambridge IGCSE – Mark Scheme PUBLISHED October/November 2017 © UCLES 2017 Page 4 of 8 Question Answer Marks 4(a)(i) → 2(C2H5OH) + 2CO2 M1 carbon dioxide made as product M2 balanced 2 4(a)(ii) any 2 from: • 37 °C • anaerobic • glucose is aqueous • yeast 2 4(b)(i) (concentrated) phosphoric acid 1 4(b)(ii) 92 If full credit is not awarded, allow 1 mark for Mr of ethene = 28 2 4(c)(i) (acidified) potassium manganate(VII) OR potassium (di)chromate(VI) 1 4(c)(ii) M1 all shared pairs of electrons correct for single bonds M2 2 shared pairs of electrons for the C=O bond M3 total of 8 electrons on each O including 4 non-bonding electrons and no additional non-bonding electrons 3 4(d)(i) partially ionised / dissociated 1

0439/41 Cambridge IGCSE – Mark Scheme PUBLISHED October/November 2017 © UCLES 2017 Page 5 of 8 Question Answer Marks 4(d)(ii) M1 (acids) have same concentration 1 M2: measure pH OR describe how to measure pH (such as use Universal Indicator) M3: lower pH corresponds to the stronger acid / hydrochloric acid OR M2: add calcium / magnesium / zinc / iron M3: faster rate of forming bubbles corresponds to the stronger acid / hydrochloric acid OR M2: rate of reaction with (metal) carbonate M3: faster rate of forming bubbles corresponds to the stronger acid / hydrochloric acid OR M2: rate of reaction with (named) metal oxide M3: dissolves faster means that reaction is with the stronger acid / hydrochloric acid OR M2: electrical conductivity M3: greater conductivity corresponds to the stronger acid / hydrochloric acid OR M2: add sodium hydroxide (or other named alkali) M3: greater temperature change corresponds to the stronger acid / hydrochloric acid 2 4(e) structure of propanoic acid 1 propanoic acid 1 structure of butan-1-ol 1 butan-1-ol 1

0439/41 Cambridge IGCSE – Mark Scheme PUBLISHED October/November 2017 © UCLES 2017 Page 6 of 8 Question Answer Marks 5(a)(i) start colour: green end colour: black 1 5(a)(ii) CuCO3 → CuO + CO2 1 5(b)(i) (copper(II) ions) add sodium hydroxide (solution) 1 (copper(II) ions) blue ppt. 1 (nitrate ions) add aluminium AND aqueous sodium hydroxide AND warm 1 ammonia given off / gas turns damp (red) litmus blue 1 5(b)(ii) 2 / 2 / 4 / 1 1 5(c)(i) becomes paler 1 equilibrium moves right 1 (because) fewer moles (of gas) on right 1 5(c)(ii) equilibrium moved right / more N2O4/ less NO2 1 (forward) reaction exothermic 1 Question Answer Marks 6(a) aluminium is more reactive than carbon 1 6(b)(i) oxide ion has an outer shell with six dots and two crosses 1 oxide ion has a charge of 2– 1

0439/41 Cambridge IGCSE – Mark Scheme PUBLISHED October/November 2017 © UCLES 2017 Page 7 of 8 Question Answer Marks 6(b)(ii) (electrostatic) forces of attraction between ions 1 (are) strong OR require lots of energy to overcome 1 6(c)(i) the wires: electrons 1 the electrolyte: ions 1 6(c)(ii) any 2 from: • increases conductivity • as a solvent • lowers the operating temperature 2 6(c)(iii) Al3+ + 3e– → Al 1 6(c)(iv) oxygen is made at the anode 1 the anodes are made of carbon 1 oxygen (made) reacts with carbon 1 6(d) aluminium coated with layer of (unreactive) aluminium oxide 1 Question Answer Marks 7(a)(i) more particles (of acid) in a given volume / dm3 / cm3 1 more collisions per second / unit time OR greater collision rate 1

0439/41 Cambridge IGCSE – Mark Scheme PUBLISHED October/November 2017 © UCLES 2017 Page 8 of 8 Question Answer Marks 7(a)(ii) particles have more energy / particles move faster / more collisions per second / more collisions per unit time / greater collision rate 1 more (of the) particles / collisions have energy greater than the activation energy / more particles have sufficient energy to react / more collisions have sufficient energy to react / a greater percentage of collisions are successful 1 7(b)(i) 0.075 If full credit is not awarded, allow 1 mark for Mr of CuO = 80 2 7(b)(ii) 0.05 1 7(b)(iii) 4 (g) M1 moles copper(II) oxide that reacted = (0.05 / 2) = 0.025 mol M2 mass copper(II) oxide = ((0.075 – 0.025) × 80) = 4 g 2 7(c) Cl2CuH4O2 M1 41.52 / 35.5; 37.43 / 64; 2.34 / 1; 18.71 / 16 OR 1.17 : 0.58 : 2.34 : 1.17 M2 appropriate scaling to give whole number ratios 2