Cambridge IGCSE Chemistry (BES) 0439 — 2018 Oct/Nov Paper 3 · 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) 0439/31 Paper 3 Theory (Core) October/November 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 16 printed pages. [Turn over IB18 11_0439_31/2RP © UCLES 2018 *5794948666*

2 0439/31/O/N/18 © UCLES 2018 1 (a) The electronic structures of five atoms, A, B, C, D and E, are shown. A B C D E Answer the following questions about these structures. Each structure may be used once, more than once or not at all. State which structure, A, B, C, D or E, represents: (i) an atom of a metallic element … [1] (ii) an atom with a proton number of 13 … [1] (iii) an atom of phosphorus … [1] (iv) an atom with only two shells of electrons … [1] (v) an atom which forms a stable ion with a single negative charge. … [1] (b) Complete the table to show the number of electrons, neutrons and protons in the carbon atom and potassium ion shown. number of electrons number of neutrons number of protons 14C 6 6 40K+ 19 21  [3]  [Total: 8]

3 0439/31/O/N/18 © UCLES 2018 [Turn over 2 (a) The table shows the ions present in a 1000 cm3 sample of blood plasma. ion present formula of ion mass present in the 1000 cm3 sample / g sodium Na+ 3.25 potassium K+ 0.16 calcium Ca2+ 0.10 magnesium Mg2+ 0.04 chloride Cl – 3.65 hydrogencarbonate HCO3 – 1.50 phosphate PO4 3– 0.64 sulfate SO4 2– 0.10 Answer these questions using only information from the table. (i) Which positive ion is present in the lowest concentration? … [1] (ii) Give the name of the compound formed from K+ and Cl – ions. … [1] (iii) Calculate the mass of potassium ions present in 200 cm3 of this blood plasma.  mass of potassium ions = … g [1] (iv) When the 1000 cm3 sample of blood plasma is crystallized, several compounds are formed. Suggest the name of the compound which forms the greatest mass of crystals. … [1] (b) Describe a test for potassium ions. test … result …  [2]

4 0439/31/O/N/18 © UCLES 2018 (c) Blood plasma also contains proteins. Proteins are present in food. Which one of the following substances is also present in food? Draw a circle around the correct answer. carbohydrate hematite poly(ethene) terylene  [1] (d) Compound S is one of the monomer units used to make proteins. Its structure is shown. H2N CH compound S CH2 COOH OH (i) On the structure, draw a circle around the alcohol functional group. [1] (ii) Deduce the molecular formula of compound S showing the number of carbon, hydrogen, oxygen and nitrogen atoms. … [1]  [Total: 9]

5 0439/31/O/N/18 © UCLES 2018 [Turn over 3 (a) The apparatus used for distillation is shown. … aqueous copper(II) sulfate thermometer flask (i) Complete the box to name the apparatus. [1] (ii) Describe and explain how the water is separated from the aqueous copper(II) sulfate by distillation. … … … … … [3] (b) A sample of solid hydrated copper(II) sulfate is heated gently in a test-tube. CuSO4.5H2O CuSO4 + 5H2O hydrated copper(II) sulfate Solid hydrated copper(II) sulfate is blue. Describe two observations when the sample of solid hydrated copper(II) sulfate is heated gently in a test-tube. 1 … 2 …  [2]

6 0439/31/O/N/18 © UCLES 2018 (c) Copper(II) sulfate can be prepared by heating an excess of copper(II) oxide with dilute sulfuric acid. (i) Complete the chemical equation for this reaction. CuO + H2SO4 CuSO4 + …  [1] (ii) What method is used to separate the excess copper(II) oxide from the solution? … [1] (d) Copper(II) oxide can be reduced by hydrogen. CuO + H2 Cu + H2O How does this equation show that copper(II) oxide is reduced? … … [1] (e) The chemical equation for the reaction of copper with concentrated nitric acid is shown. Cu + 4HNO3 Cu(NO3)2 + 2NO2 + 2H2O Complete the word equation for this reaction. copper + nitric acid … … + … … + …  [2]  [Total: 11]

7 0439/31/O/N/18 © UCLES 2018 [Turn over 4 (a) The structure of citraconic acid is shown. C C H COOH COOH H3C Citraconic acid is an unsaturated compound. (i) What feature of the structure of citraconic acid shows that it is unsaturated? … [1] (ii) Describe a test for an unsaturated compound. test … result …  [2] (b) Ethanoic acid has a carboxylic acid functional group. Draw the structure of the carboxylic acid functional group. Show all of the atoms and all of the bonds.  [1] (c) Complete the definition of a homologous series using words from the list. chemical compounds elements functional hydrocarbons physical A homologous series is a family of similar … with similar … properties due to the presence of the same … group. [3]

8 0439/31/O/N/18 © UCLES 2018 (d) The graph shows how the pH of a dilute acid in an Erlenmeyer flask changes as aqueous sodium hydroxide is added to it. 14 12 10 8 6 4 2 0 0 5 10 15 20 volume of aqueous sodium hydroxide added / cm3 25 30 35 pH (i) Describe how the pH changes as the aqueous sodium hydroxide is added. … … … [2] (ii) What is the pH of the dilute acid before the aqueous sodium hydroxide is added? … [1] (iii) What volume of aqueous sodium hydroxide has been added when the pH reaches pH 7? … [1]  [Total: 11]

9 0439/31/O/N/18 © UCLES 2018 [Turn over 5 (a) Some of the changes of state of water are shown. ice water water vapour P freezing Q evaporation (i) Give the names of the changes of state represented by P and Q. P … Q …  [2] (ii) Use the kinetic particle model to describe the separation and motion of the particles in water when it is: ● ● a liquid … … ● ● a vapor … …  [4] (b) When lithium reacts with water, hydrogen is produced and the solution formed is alkaline. (i) Balance the chemical equation for this reaction. …Li + …H2O 2LiOH + H2  [2] (ii) Give the name of the product which causes the solution to be alkaline. … [1]

10 0439/31/O/N/18 © UCLES 2018 (c) Dilute sulfuric acid can be electrolyzed using the apparatus shown. power supply dilute sulfuric acid graphite electrodes + – (i) State the products of this electrolysis at: the positive electrode (anode) … the negative electrode (cathode). …  [2] (ii) What observation is made at the electrodes? … [1] (iii) Suggest one reason why graphite is used for the electrodes rather than magnesium. … [1]  [Total: 13]

11 0439/31/O/N/18 © UCLES 2018 [Turn over 6 (a) The diagrams show the structures of four substances, R, S, T and U. C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C Zn Zn Zn Zn Zn Zn Zn Zn Zn Zn Zn Na+ Br – Na+ Na+ Br – Na+ Br – Br – Na+ P P P P R S T U (i) Which two of these substances, R, S, T or U, are covalently bonded? … and … [2] (ii) Which two of these substances, R, S, T or U, conduct electricity when solid? … and … [2] (iii) Which substance, R, S, T or U, has the lowest melting point? … [1] (iv) Which one of these substances, R, S, T or U, is soluble in water? … [1] (b) Phosphorus burns in oxygen to form phosphorus(V) oxide. (i) Balance the chemical equation for this reaction. P4 + 5O2 …P2O5 [1] (ii) Is phosphorus(V) oxide an acidic oxide or a basic oxide? Give a reason for your answer. … … [1] (c) Phosphate ions are present in many fertilizers. (i) Which one of the following ions is also present in many fertilizers? Draw a circle around the correct answer. Ba2+ Cu2+ F– NO3 – [1] (ii) Why do farmers put fertilizers on their fields? … … [1]  [Total: 10]

12 0439/31/O/N/18 © UCLES 2018 7 (a) A student investigates the reaction of calcium carbonate with dilute hydrochloric acid. CaCO3 + 2HCl CaCl 2 + CO2 + H2O The student measures the mass of the reaction mixture at 10 second intervals using the apparatus shown. 250.00 g calcium carbonate cotton wool dilute hydrochloric acid The graph shows the results when 5.0 g of calcium carbonate is added to an excess of dilute hydrochloric acid. 250 249 248 247 246 0 10 20 30 40 time / s mass / g 50 60 70 80 (i) Suggest why the reaction mixture decreases in mass as the reaction proceeds. … [1] (ii) Calculate the loss of mass in grams when the reaction is complete.  loss in mass = … g [1]

13 0439/31/O/N/18 © UCLES 2018 [Turn over (iii) The experiment is repeated using dilute hydrochloric acid of twice the concentration. All other conditions are kept the same. On the grid, draw a graph to show how the mass changes with time using dilute hydrochloric acid of twice the concentration. [2] (iv) The original experiment is repeated at three different temperatures. All other conditions are kept the same. The three temperatures are 20 °C, 30 °C and 40 °C. Complete the table by writing the temperatures in the first column. temperature in °C initial rate of reaction in g / s 0.16 0.64 0.32  [1] (b) Complete the sentences about the use of calcium carbonate in the extraction of iron using words from the list. bauxite dioxide hematite monoxide silicon slag The main ore of iron is called … . The main impurity in the iron ore is silicon(IV) oxide. Calcium carbonate added to the blast furnace decomposes to form calcium oxide and carbon … . The calcium oxide reacts with the silicon(IV) oxide to form … .  [3]  [Total: 8]

14 0439/31/O/N/18 © UCLES 2018 8 Glass can be made by heating a mixture of sand, sodium carbonate and limestone (calcium carbonate). (a) (i) Calculate the relative formula mass of sodium carbonate, Na2CO3. Show all your working. Use your Periodic Table to help you.  relative formula mass = … [2] (ii) Sodium carbonate can be manufactured by the reaction between limestone and sodium chloride. The reaction is endothermic. What is meant by the term endothermic? … [1] (iii) During this glass-making process, limestone decomposes into lime (calcium oxide). Lime is used to treat acidic soils. What type of chemical reaction occurs when lime reacts with acidic soils? Draw a circle around the correct answer. addition neutralization oxidation reduction  [1]

15 0439/31/O/N/18 © UCLES 2018 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) Charcoal (carbon) can be burned in an excess of clean, dry air to provide the heat needed to make glass. (i) Which gas is 21% of clean, dry air? … [1] (ii) Write a word equation for carbon burning in an excess of air. … [1] (iii) Complete the energy level diagram for this reaction by adding these two words: ● reactants ● product energy progress of reaction  [1] (c) Argon is also present in clean, dry air. (i) Give one use of argon. … [1] (ii) Which two of the following statements about argon are correct? Tick two boxes. Argon is unreactive. Argon is diatomic. Argon is monatomic. Argon forms ionic compounds. Argon is a greenhouse gas.  [2]  [Total: 10]

16 0439/31/O/N/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 –

This document consists of 9 printed pages. © UCLES 2018 [Turn over Cambridge Assessment International Education Cambridge International General Certificate of Secondary Education CHEMISTRY (US) 0439/31 Paper 3 Core Theory October/November 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 October/November 2018 series for most Cambridge IGCSE™, Cambridge International A and AS Level components and some Cambridge O Level components.

0439/31 Cambridge IGCSE – Mark Scheme PUBLISHED October/November 2018 © UCLES 2018 Page 2 of 9 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.

0439/31 Cambridge IGCSE – Mark Scheme PUBLISHED October/November 2018 © UCLES 2018 Page 3 of 9 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.

0439/31 Cambridge IGCSE – Mark Scheme PUBLISHED October/November 2018 © UCLES 2018 Page 4 of 9 Question Answer Marks 1(a)(i) C 1 1(a)(ii) C 1 1(a)(iii) E 1 1(a)(iv) D 1 1(a)(v) A 1 1(b) electrons in K+: 18 (1) neutrons in C–14: 8 (1) protons in C 6 AND K+ 19 (1) 3 Question Answer Marks 2(a)(i) Mg2+ / magnesium 1 2(a)(ii) potassium chloride 1 2(a)(iii) 0.032 (g) 1 2(a)(iv) sodium chloride 1 2(b) flame test / description of flame test (1) flame coloured lilac (1) 2 2(c) carbohydrate 1 2(d)(i) OH ringed 1 2(d)(ii) C3H7NO3 1

0439/31 Cambridge IGCSE – Mark Scheme PUBLISHED October/November 2018 © UCLES 2018 Page 5 of 9 Question Answer Marks 3(a)(i) (Liebig) condenser (1) 1 3(a)(ii) One mark each for any three of: • water has lower boiling point than copper(II) sulfate • heat the aqueous copper(II) sulfate • water turns to steam but copper(II) sulfate remains (in flask) • steam turns to liquid in condenser 3 3(b) colourless liquid collects / condenses at top of the tube (1) copper(II) sulfate turns white (1) 2 3(c)(i) H2O 1 3(c)(ii) filtration / filter 1 3(d) oxygen removed from the copper oxide / copper oxide loses oxygen / it loses oxygen (1) 1 3(e) (copper + nitric acid) → copper nitrate + nitrogen dioxide + water (2) If 2 marks not scored: 1 mark for correct names of two products 2 Question Answer Marks 4(a)(i) has C=C (double bond ) 1 4(a)(ii) aqueous bromine / bromine water / bromine AND (bromine) decolourised / goes colourless (2) aqueous bromine / bromine water / bromine (for 1 mark) 2 4(b) correct structure of carboxylic acid group showing C=O and –O-H 1

0439/31 Cambridge IGCSE – Mark Scheme PUBLISHED October/November 2018 © UCLES 2018 Page 6 of 9 Question Answer Marks 4(c) compounds (1) chemical (1) functional (1) 3 4(d)(i) One mark each for any two of: • not much increase / gradual increase in pH at first • sudden increase in pH as more sodium hydroxide added • not much increase / gradual increase in pH when sodium hydroxide in excess 2 4(d)(ii) pH 2.4 1 4(d)(iii) 23 (cm3) 1 Question Answer Marks 5(a)(i) P = melting (1) Q = condensing (1) 2 5(a)(ii) liquid: motion: moving (more) slowly / sliding over each other / moving randomly / restricted movement (1) separation: close together / touching (1) gas: motion: moving rapidly / moving randomly / move everywhere (1) separation: far apart (1) 4 5(b)(i) 2 (Li) (1) 2 (H2O) (1) 2

0439/31 Cambridge IGCSE – Mark Scheme PUBLISHED October/November 2018 © UCLES 2018 Page 7 of 9 Question Answer Marks 5(b)(ii) lithium hydroxide 1 5(c)(i) positive electrode: oxygen (1) negative electrode: hydrogen (1) 2 5(c)(ii) bubbles / effervescence (1) 1 5(c)(iii) graphite is inert / unreactive / does not react with the electrolyte ORA 1 Question Answer Marks 6(a)(i) S (1) U (1) 2 6(a)(ii) R (1) U (1) 2 6(a)(iii) S (1) 1 6(a)(iv) T (1) 1 6(b)(i) 2 (P2O5) 1 6(b)(ii) acidic because phosphorus is a non-metal 1 6(c)(i) NO3 – 1 6(c)(ii) to promote plant growth / to replenish minerals from the soil which have been absorbed by crop plants 1

0439/31 Cambridge IGCSE – Mark Scheme PUBLISHED October/November 2018 © UCLES 2018 Page 8 of 9 Question Answer Marks 7(a)(i) carbon dioxide released / gas released 1 7(a)(ii) 2.2 (g) 1 7(a)(iii) initial gradient of line steeper and starts at 250–0 (1) levels out at 247.8 g (1) 2 7(a)(iv) 20 °C → 0.16 40 °C → 0.64 30 °C → 0.32 1 7(b) hematite (1) dioxide (1) slag (1) 3 Question Answer Marks 8(a)(i) 106 (2) If 2 marks not given: 1 mark for (Na) = 23, (C) = 12 and (O) = 16 2 8(a)(ii) absorbs heat / takes in heat 1 8(a)(iii) neutralisation 1 8(b)(i) oxygen / O2 1 8(b)(ii) carbon + oxygen → carbon dioxide 1 8(b)(iii) reactants on the left and product on the right (both required) 1 8(c)(i) any suitable use e.g. filling (old-fashioned light) bulbs / lamps / inert gas in stopping oxidations / welding 1

0439/31 Cambridge IGCSE – Mark Scheme PUBLISHED October/November 2018 © UCLES 2018 Page 9 of 9 Question Answer Marks 8(c)(ii) 1st box ticked (argon unreactive) (1) 3rd box ticked (argon monoatomic) (1) 2