Cambridge IGCSE Chemistry (BES) 0439 — 2018 May/June Paper 3 · Variant 3

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 20. 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) 0439/33 Paper 3 Theory (Core) May/June 2018  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 17 printed pages and 3 blank pages. [Turn over IB18 06_0439_33/FP © UCLES 2018 *3223677027*

2 0439/33/M/J/18 © UCLES 2018 1 The names of seven gases are given. ammonia ethene helium hydrogen hydrogen chloride methane nitrogen (a) Answer the following questions about these gases. Each gas may be used once, more than once or not at all. State which gas: (i) forms an acidic solution in water … [1] (ii) is monatomic … [1] (iii) forms 78% of clean dry air … [1] (iv) is the main constituent of natural gas … [1] (v) has molecules which each contain 14 protons. … [1] (b) (i) Give the names of two elements in the list. … and …  [1] (ii) What is meant by the term element ? … [1]

3 0439/33/M/J/18 © UCLES 2018 [Turn over (c) Complete the dot-and-cross diagram to show the electron arrangement in a molecule of hydrogen chloride. Show outer electrons only. H Cl  [2]  [Total: 9]

4 0439/33/M/J/18 © UCLES 2018 2 (a) The table shows the percentage by volume of each of the gases present in the exhaust gases from a gasoline engine and a diesel engine. name percentage by volume from a gasoline engine percentage by volume from a diesel engine nitrogen 72.00 67.00 carbon dioxide 14.00 water vapor 12.00 11.00 carbon monoxide 1.50 0.05 oxides of nitrogen 0.25 0.70 hydrocarbons 0.24 0.22 sulfur dioxide 0.01 0.03 oxygen 0.00 9.00 total 100.00 total 100.00 (i) In the diesel engine, nitrogen, carbon dioxide and water vapor account for 90.00% of the exhaust gases by volume. Calculate the percentage by volume of carbon dioxide in the exhaust gases from the diesel engine.  …% [1] (ii) Describe three ways in which the composition of the exhaust gases from the gasoline engine differ from the composition of the exhaust gases from the diesel engine. 1 … 2 … 3 …  [3] (iii) Give one adverse effect of sulfur dioxide on health. … [1]

5 0439/33/M/J/18 © UCLES 2018 [Turn over (b) Complete the sentences about the separation of petroleum into fractions using words from the list. boiling crystallization density distillation kerosene poly(ethene) Fractional … of petroleum produces fractions such as gasoline, diesel oil and … . Within each fraction, the molecules have a particular range of … points.  [3] (c) Balance the chemical equation for the complete combustion of propane. C3H8 + 5O2 …CO2 + …H2O  [2]  [Total: 10]

6 0439/33/M/J/18 © UCLES 2018 3 This question is about cobalt and its compounds. (a) A colored crystal of cobalt(II) chloride was placed at the bottom of a beaker containing water. After 2 days, the color had spread throughout the water. at the start after 2 hours after 2 days crystal of cobalt(II) chloride water Explain these observations using the kinetic particle model. … … … … … [3] (b) Cobalt(II) chloride can be used to test for the presence of water. CoCl 2 + 6H2O CoCl 2.6H2O anhydrous hydrated cobalt(II) chloride cobalt(II) chloride (i) What is meant by the symbol ? … [1] (ii) Describe how the color of anhydrous cobalt(II) chloride changes when water is added to it. from … to …  [2] (c) A compound of cobalt can be represented by the structure shown. = cobalt, Co = carbon, C = oxygen, O key Deduce the molecular formula of this compound showing the number of cobalt, carbon and oxygen atoms. … [1]

7 0439/33/M/J/18 © UCLES 2018 [Turn over (d) The table compares the reactivity of cobalt with that of three other metals. metal reactivity with cold water reactivity with steam barium reacts rapidly cobalt no reaction reacts slowly when heated magnesium reacts very slowly reacts rapidly zinc no reaction reacts easily when heated Use this information to put the metals in order of their reactivity. Put the least reactive metal first. least reactive most reactive  [2] (e) Cobalt is a transition element. Lithium is an element in Group I of the Periodic Table. Describe three ways in which the properties of cobalt differ from those of lithium. 1 … 2 … 3 …  [2] (f) When cobalt(II) oxide, CoO, is heated in air, an oxide with the formula Co3O4 is formed. Balance the chemical equation for this reaction. …CoO + O2 2Co3O4  [1] (g) When Co3O4 is heated with hydrogen, cobalt metal can be formed. Co3O4 + 4H2 3Co + 4H2O How does this equation show that Co3O4 is reduced? … … [1]  [Total: 13]

8 0439/33/M/J/18 © UCLES 2018 4 This question is about alcohols. (a) The structure of compound P is shown. C O H H C C H H H H (i) What feature of the structure of compound P shows that it is unsaturated? … [1] (ii) Describe how the color of aqueous bromine changes when an excess of compound P is added to it. from … to …  [2] (iii) The melting point of compound P is –129 °C. The boiling point of compound P is 97 °C. What is the physical state of compound P at –120 °C? Explain your answer. … … [2] (b) Ethanol is an alcohol with two carbon atoms. (i) Draw the structure of ethanol showing all of the atoms and all of the bonds.  [1]

9 0439/33/M/J/18 © UCLES 2018 [Turn over (ii) Ethanol can be manufactured by fermentation. Complete the sentences about fermentation using words from the list. 30 °C 300 °C distillation electrolysis elements enzymes salt sugar A flask containing … solution and yeast is heated to … . The yeast contains … which catalyze the reaction. The ethanol is separated by … . [4] (iii) Ethanol can be used as a fuel. Give one other use of ethanol in industry. … [1] (iv) The energy level diagram for the complete combustion of ethanol is shown. energy ethanol + oxygen carbon dioxide + water progress of reaction Explain how this diagram shows that the reaction is exothermic. … … [1] (v) Carbon dioxide and water can be formed when ethanol burns in a limited supply of air. State the name of two other products which can be formed when ethanol burns in a limited supply of air. … and …  [2]  [Total: 14]

10 0439/33/M/J/18 © UCLES 2018 5 (a) Molten lead(II) bromide can be electrolyzed using the apparatus shown. molten lead(II) bromide inert electrodes + – The negative electrode is called the cathode. State the name of the positive electrode. … [1] (b) Predict the products of the electrolysis of molten lead(II) bromide at: the negative electrode … the positive electrode. …  [2] (c) Lead(II) bromide is insoluble in cold water. Sodium bromide is soluble in cold water. Describe how you could obtain crystals of sodium bromide from a mixture of solid lead(II) bromide and solid sodium bromide. … … … … [3] (d) When chlorine is bubbled through a colorless aqueous solution of sodium bromide, the solution turns orange‑brown. Name the orange-brown substance. Suggest, using ideas about reactivity of the halogens, why the reaction occurs. orange-brown substance … why the reaction occurs … …  [2]

11 0439/33/M/J/18 © UCLES 2018 [Turn over (e) What is the color of the precipitate formed when aqueous silver nitrate is added to aqueous sodium bromide? … [1] (f) Complete the sentence about the formation of a chloride ion from a chlorine atom. A chloride ion is formed when a chlorine atom gains one … . [1]  [Total: 10]

12 0439/33/M/J/18 © UCLES 2018 6 This question is about isotopes. (a) An atom of an isotope of oxygen is represented by the symbol shown. 17O 8 Describe the structure of an atom of this isotope of oxygen. In your answer, include: ● ● the position of the protons, neutrons and electrons in the atom ● ● the number of protons, neutrons and electrons present in the atom. … … … … … … … [5] (b) Which two statements about isotopes are correct? Tick two boxes. Isotopes of the same element have different numbers of protons. Isotopes of the same element have different numbers of neutrons. Isotopes are always radioactive. The isotope 235U 92 is a source of energy. 14C 6 and 14N 7 are isotopes of each other.  [2] (c) What is meant by the term nucleon number? … … [1]  [Total: 8]

13 0439/33/M/J/18 © UCLES 2018 [Turn over 7 This question is about Group I elements and their compounds. (a) The properties of some Group I elements are shown in the table. element melting point / °C relative hardness observations when it reacts with cold water lithium 181 23 sodium 98 3 rapid bubbling but does not burst into flame potassium 63 very rapid bubbling and bursts into flame rubidium 1 bursts into flame and explodes (i) Complete the table to estimate: ● ● the relative hardness of potassium ● ● the melting point of rubidium.  [2] (ii) Use the information in the table to predict what you would observe when lithium reacts with cold water. … [1] (b) Write the electronic structure of a sodium atom. … [1] (c) When sodium reacts with water, an alkaline solution is formed. 2Na + 2H2O 2NaOH + H2 (i) Use the information in the equation to explain why the solution formed is alkaline. … [1] (ii) Describe how you could use a named indicator solution to show that the solution is alkaline. … … [2]

14 0439/33/M/J/18 © UCLES 2018 (d) Sodium tetrahydridoborate, NaBH4, is an ionic compound. Calculate the relative formula mass of NaBH4. Show all your working. Use your Periodic Table to help you.  relative formula mass = … [2]  [Total: 9]

15 0439/33/M/J/18 © UCLES 2018 [Turn over 8 The apparatus shown is used to investigate the rate of reaction between calcium carbonate and hydrochloric acid at 30 °C. water hydrochloric acid A calcium carbonate (a) Name the piece of apparatus labeled A in the diagram. … [1] (b) Describe how this apparatus can be used to find the rate of reaction. … … … [2] (c) The experiment is repeated at 20 °C. All other conditions are kept the same. How does the decrease in temperature affect the rate of reaction? … [1] (d) The experiment is repeated using the same mass of different size pieces of calcium carbonate. All other conditions are kept the same. The sizes of the pieces of calcium carbonate are: ● ● large pieces ● ● small pieces ● ● powder Complete the table by writing the sizes of the pieces in the first column. size of the pieces of calcium carbonate initial rate of reaction in cm3 gas / s 5 2 12  [1]

16 0439/33/M/J/18 © UCLES 2018 (e) Give the names of the three products formed when calcium carbonate reacts with hydrochloric acid. 1 … 2 … 3 …  [2]  [Total: 7]

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19 0439/33/M/J/18 © UCLES 2018 BLANK PAGE 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.

20 0439/33/M/J/18 © UCLES 2018 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 12 printed pages. © UCLES 2018 [Turn over Cambridge Assessment International Education Cambridge International General Certificate of Secondary Education CHEMISTRY (US) 0439/33 Paper 3 Theory (Core) May/June 2018 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 May/June 2018 series for most Cambridge IGCSE™, Cambridge International A and AS Level and Cambridge Pre-U components, and some Cambridge O Level components.

0439/33 Cambridge IGCSE – Mark Scheme PUBLISHED May/June 2018 © UCLES 2018 Page 2 of 12 Generic Marking Principles These general marking principles must be applied by all examiners when marking candidate answers. They should be applied alongside the specific content of the mark scheme or generic level descriptors for a question. Each question paper and mark scheme will also comply with these marking principles. GENERIC MARKING PRINCIPLE 1: Marks must be awarded in line with: • the specific content of the mark scheme or the generic level descriptors for the question • the specific skills defined in the mark scheme or in the generic level descriptors for the question • the standard of response required by a candidate as exemplified by the standardisation scripts. GENERIC MARKING PRINCIPLE 2: Marks awarded are always whole marks (not half marks, or other fractions). GENERIC MARKING PRINCIPLE 3: Marks must be awarded positively: • marks are awarded for correct/valid answers, as defined in the mark scheme. However, credit is given for valid answers which go beyond the scope of the syllabus and mark scheme, referring to your Team Leader as appropriate • marks are awarded when candidates clearly demonstrate what they know and can do • marks are not deducted for errors • marks are not deducted for omissions • answers should only be judged on the quality of spelling, punctuation and grammar when these features are specifically assessed by the question as indicated by the mark scheme. The meaning, however, should be unambiguous. GENERIC MARKING PRINCIPLE 4: Rules must be applied consistently e.g. in situations where candidates have not followed instructions or in the application of generic level descriptors.

0439/33 Cambridge IGCSE – Mark Scheme PUBLISHED May/June 2018 © UCLES 2018 Page 3 of 12 GENERIC MARKING PRINCIPLE 5: Marks should be awarded using the full range of marks defined in the mark scheme for the question (however; the use of the full mark range may be limited according to the quality of the candidate responses seen). GENERIC MARKING PRINCIPLE 6: Marks awarded are based solely on the requirements as defined in the mark scheme. Marks should not be awarded with grade thresholds or grade descriptors in mind.

0439/33 Cambridge IGCSE – Mark Scheme PUBLISHED May/June 2018 © UCLES 2018 Page 4 of 12 Question Answer Marks 1(a)(i) hydrogen chloride / HCl 1 1(a)(ii) helium / He 1 1(a)(iii) nitrogen / N2 1 1(a)(iv) methane / CH4 1 1(a)(v) nitrogen / N2 1 1(b)(i) One mark each for any 2 of: • helium • hydrogen • nitrogen 1 1(b)(ii) (substance) containing only one type of atom / (substance) which cannot be broken down chemically into any other substance 1 1(c) bonding pair of electrons between H and Cl 1 6 non-bonding electrons on the Cl and none on the H 1

0439/33 Cambridge IGCSE – Mark Scheme PUBLISHED May/June 2018 © UCLES 2018 Page 5 of 12 Question Answer Marks 2(a)(i) 12(%) 1 2(a)(ii) One mark each for any 3 of: • more nitrogen in petrol engine / ORA for diesel • more carbon dioxide in petrol engine / ORA for diesel • more water vapour in petrol engine / ORA for diesel • more carbon monoxide in petrol engine / ORA for diesel • less oxides of nitrogen in petrol engine / ORA for diesel • more hydrocarbons in petrol engine / ORA for diesel • less sulfur dioxide in petrol engine / ORA for diesel • less / no oxygen in petrol engine / ORA for diesel 3 2(a)(iii) breathing difficulties / irritates eyes / irritates nose / irritates throat / irritates lungs / (potentiates) asthma 1 2(b) distillation 1 kerosene 1 boiling 1 2(c) 3 (CO2) 1 4 (H2O) 1

0439/33 Cambridge IGCSE – Mark Scheme PUBLISHED May/June 2018 © UCLES 2018 Page 6 of 12 Question Answer Marks 3(a) One mark each for any 3 of: • (cobalt / chloride) particles go from close together to spread out / (cobalt / chloride) particles go into solution / (cobalt / chloride) particles go into the water • diffusion • random movement of particles / particles move anywhere (in the liquid) / particles move in all directions • spreading out of particles / intermingling of particles / mixing of particles / particles collide / particles bounce off each other / particles go all over • (bulk) movement of particles from higher to lower concentration / movement of particles down concentration gradient 3 3(b)(i) reversible reaction 1 3(b)(ii) blue 1 to pink 1 3(c) Co2C8O8 1 3(d) cobalt<zinc<magnesium<barium IF 2 marks not scored: 1 mark if all reversed / one consecutive pair reversed 2

0439/33 Cambridge IGCSE – Mark Scheme PUBLISHED May/June 2018 © UCLES 2018 Page 7 of 12 Question Answer Marks 3(e) 3 of the following correct = 2 marks 1 or 2 of the following correct = 1 mark • Co has high melting point / boiling point ORA for lithium • Co has high density ORA for lithium • Co has catalytic activity ORA for lithium • Co forms coloured compounds ORA for lithium • Co compounds have variable oxidation states / form ions with different charges ORA • iron is hard / lithium is soft(er) / iron is strong / lithium is weak • one suitable difference in chemical properties e.g. cobalt is less reactive ORA / lithium reacts with cold water • cobalt is magnetic / ORA for lithium 2 3(f) 6 (CoO) 1 3(g) Co3O4 loses oxygen / it loses oxygen / oxygen is removed from the cobalt oxide / the cobalt oxide loses oxygen 1

0439/33 Cambridge IGCSE – Mark Scheme PUBLISHED May/June 2018 © UCLES 2018 Page 8 of 12 Question Answer Marks 4(a)(i) C=C double bond 1 4(a)(ii) orange / red-brown / brown 1 to colourless 1 4(a)(iii) liquid 1 –120 ºC is in between the melting point and boiling point / –120 ºC is higher than the melting point AND lower than the boiling point 1 4(b)(i) correct structure of ethanol showing all atoms and all bonds 1 4(b)(ii) sugar 1 30 ºC 1 enzymes 1 distillation 1 4(b)(iii) any suitable use e.g. solvent / to make named chemical 1 4(b)(iv) energy level of reactants above energy level of products / the arrow is going downwards / energy (level) goes down / product has less energy than reactants 1 4(b)(v) carbon monoxide 1 carbon 1

0439/33 Cambridge IGCSE – Mark Scheme PUBLISHED May/June 2018 © UCLES 2018 Page 9 of 12 Question Answer Marks 5(a) anode 1 5(b) negative electrode: lead 1 positive electrode: bromine 1 5(c) add (sufficient) water and stir (to dissolve) / add the mixture to water 1 filter off the lead bromide / filter to obtain solution sodium bromide 1 evaporate (some of the) water from the solution / warm solution to crystallisation point then leave (to crystallise) 1 5(d) bromine 1 chlorine is more reactive than bromine 1 5(e) cream 1 5(f) electron 1

0439/33 Cambridge IGCSE – Mark Scheme PUBLISHED May/June 2018 © UCLES 2018 Page 10 of 12 Question Answer Marks 6(a) One mark each for any 5 of: • protons in the nucleus / centre (of the atom) • neutrons in the nucleus / centre of the atom • electrons outside the nucleus / electrons surrounding the nucleus / electrons orbiting the nucleus • 8 protons • 8 electrons • 9 neutrons 5 6(b) 2nd box down ticked 1 4th box down ticked 1 6(c) number of protons plus neutrons in an atom 1

0439/33 Cambridge IGCSE – Mark Scheme PUBLISHED May/June 2018 © UCLES 2018 Page 11 of 12 Question Answer Marks 7(a)(i) relative hardness of potassium: between 1 and 3 (exclusive of these two values) 1 melting point of rubidium: less than 63 ºC but not lower than 20 ºC 1 7(a)(ii) slow bubbling / fewer bubbles than sodium 1 7(b) 2,8,1 1 7(c)(i) Group I hydroxide is alkaline / sodium hydroxide is an alkali 1 7(c)(ii) add (red) litmus OR add universal / full range indicator 1 turns blue OR turns blue / purple 1 7(d) 38 IF two marks not scored: 1 mark for (B =) 11, (Na =) 23, (H =) 1 2

0439/33 Cambridge IGCSE – Mark Scheme PUBLISHED May/June 2018 © UCLES 2018 Page 12 of 12 Question Answer Marks 8(a) measuring cylinder 1 8(b) measure the volume of gas given off / measure volume of carbon dioxide produced OR measure time taken 1 over a given time(s) OR to produce given volume(s) of gas 1 8(c) decreases rate / decreases it / makes it slower 1 8(d) small pieces AND large pieces AND powder 1 8(e) calcium chloride 1 carbon dioxide AND water 1