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Đề thi môn hoá chính thức hệ Cambridge IGCSE™ Chemistry, đề thi bao gồm đề trắc nghiệm (multiple choice) và đề tự luận (Theory). Ngoài ra còn chia hai hệ cơ bản (core) và hệ nâng cao (extended) giúp các bạn học sinh có thể lựa chọn đề phù hợp nhất.
Cambridge IGCSE™ *7173648614* CHEMISTRY0620/31 May/June 2023 Paper Theory (Core) hour 15 minutes You must answer on the question paper No additional materials are needed INSTRUCTIONS ● Answer all questions ● Use a black or dark blue pen You may use an HB pencil for any diagrams or graphs ● Write your name, centre number and candidate number in the boxes at the top of the page ● Write your answer to each question in the space provided ● Do not use an erasable pen or correction fluid ● Do not write on any bar codes ● You may use a calculator ● You should show all your working and use appropriate units INFORMATION ● The total mark for this paper is 80 ● The number of marks for each question or part question is shown in brackets [ ] ● The Periodic Table is printed in the question paper This document has 16 pages IB23 06_0620_31/2RP © UCLES 2023 [Turn over 1 Fig. 1.1 shows part of the Periodic Table I II III IV V VI VII VIII H He C Na Mg K Ca N O Al Fe Cu Cl Br I Fig 1.1 Answer the following questions using only the elements in Fig. 1.1 Each symbol of the element may be used once, more than once or not at all Give the symbol of the element that: (a) forms 78% by volume of clean, dry air [1] (b) has an atom with a complete outer electron shell [1] (c) has an atom with five occupied electron shells [1] (d) forms an ion with a charge of 2– [1] (e) forms an ion that gives a green precipitate on addition of aqueous sodium hydroxide [1] (f) is used in food containers because of its resistance to corrosion [1] [Total: 6] © UCLES 2023 0620/31/M/J/23 (a) Table 2.1 shows some properties of the halogens Table 2.1 halogen melting point in °C boiling point in °C density at room temperature and pressure in g / cm3 fluorine –220 –188 0.0016 chlorine –101 –35 0.0032 +59 3.1 bromine iodine +114 +184 Use the information in Table 2.1 to predict: (i) the melting point of bromine ��������������������������������������������������������������������������������������������������������������������������������������� [1] (ii) the density of iodine at room temperature and pressure ��������������������������������������������������������������������������������������������������������������������������������������� [1] (iii) the physical state of chlorine at –10 °C Give a reason for your answer physical state reason [2] (b) The equation for the reaction of aqueous chlorine with aqueous potassium iodide is shown Cl 2 + 2KI → I2 + 2KCl (i) Choose the word which best describes this type of chemical reaction Draw a circle around your chosen answer addition displacement neutralisation polymerisation[1] (ii) Explain why aqueous iodine does not react with aqueous potassium chloride © UCLES 2023 [1] 0620/31/M/J/23 [Turn over (c) Complete the diagram in Fig. 2.1 to show the electronic configuration of a chlorine atom Cl Fig 2.1 [1] (d) Describe a test for chlorine test observations [2] © UCLES 2023 [Total: 9] 0620/31/M/J/23 (a) Water from natural sources contains dissolved gases Choose from the list, the gas that is essential for aquatic life Draw a circle around your chosen answer argon oxygen[1] (i) Name one other harmful substance which is present in polluted water [1] (ii) State why nitrates are harmful to aquatic life nitrogen (b) Polluted water may contain harmful substances such as metal compounds, plastics, nitrates and phosphates hydrogen [1] (c) Table 3.1 shows the masses of ions, in mg, present in a 1000 cm3 sample of polluted water Table 3.1 formula of ion mass of ion present in mg / 1000 cm3 of polluted water NH4+ 0.5 calcium Ca2+ 2.2 chloride Cl – 2.5 HCO3– 12.0 magnesium Mg2+ 0.8 nitrate NO3– 0.4 K+ 8.3 silicate SiO32– 8.0 sodium Na+ 10.2 sulfate SO42– 0.2 tin(II) Sn2+ 0.4 name of ion hydrogencarbonate potassium Answer these questions using information from Table 3.1 (i) Name the negative ion present in the highest concentration [1] (ii) State the name of the NH4+ ion © UCLES 2023 [1] 0620/31/M/J/23 [Turn over (iii) Calculate the mass of calcium ions present in 200 cm3 of polluted water mass = mg [1] (d) Copper(II) sulfate can be used to test for the presence of water CuSO4(s) + 5H2O(l) CuSO4•5H2O(s) anhydrous hydrated copper(II) sulfate copper(II) sulfate (i) State the meaning of the term hydrated [1] (ii) Describe how hydrated copper(II) sulfate is changed to anhydrous copper(II) sulfate [1] (e) Complete the symbol equation for the reaction of sodium with water 2Na + .H2O → 2NaOH + © UCLES 2023 [2] [Total: 10] 0620/31/M/J/23 4 This question is about sulfur and compounds of sulfur (a) Sulfur has several isotopes Define the term isotopes [2] (b) Deduce the number of protons, neutrons and electrons in the sulfide ion shown 36 2– 16S number of protons number of neutrons number of electrons [3] (c) Sulfur burns in oxygen to produce sulfur dioxide Fig. 4.1 shows an incomplete reaction pathway diagram for this reaction energy progress of reaction Fig 4.1 (i) Complete Fig. 4.1 by writing these formulae on the diagram: ● S + O2 ● SO2.[1] (ii) Explain how Fig. 4.1 shows that the reaction is exothermic [1] (iii) Complete this sentence about an exothermic reaction using a word from the list products reactants sulfur surroundings An exothermic reaction transfers thermal energy to the . © UCLES 2023 0620/31/M/J/23 [1] [Turn over (d) Fig. 4.2 shows the apparatus used for the electrolysis of dilute sulfuric acid using graphite electrodes power + supply – Fig 4.2 (i) Label Fig. 4.2 to show: ● the cathode ● the electrolyte. [2] (ii) Name the products and state the observations at the positive and negative electrodes product at the positive electrode observations at the positive electrode product at the negative electrode observations at the negative electrode [4] (e) Complete the word equation for the reaction of dilute sulfuric acid with sodium carbonate sulfuric acid + sodium carbonate + + [3] (f) A few drops of thymolphthalein indicator are added to dilute sulfuric acid State the colour of the solution [1] [Total: 18] © UCLES 2023 0620/31/M/J/23 5 This question is about metals (a) Iron is a transition element Potassium is an element in Group I of the Periodic Table State two differences in the physical properties of iron compared to potassium [2] (b) Carbon is used to extract iron from iron ore in a blast furnace State two uses of carbon in the extraction process [2] (c) Steel is an alloy of iron (i) State the meaning of the term alloy [1] (ii) State why alloys are more useful than pure metals [1] (d) T able 5.1 shows the observations made when four different metals react with dilute hydrochloric acid of the same concentration Table 5.1 metal observations iron bubbles form slowly lead no bubbles formed magnesium bubbles form rapidly nickel bubbles form very slowly Put the four metals in order of their reactivity Put the least reactive metal first least reactive most reactive [2] © UCLES 2023 [Total: 8] 0620/31/M/J/23 [Turn over 10 6 (a) A student investigates the reaction of small pieces of zinc of the same mass and size with three different concentrations of dilute hydrochloric acid in the presence of a catalyst The three concentrations of dilute hydrochloric acid are: ● 1.0 mol / dm3 ● 1.5 mol / dm3 ● 2.0 mol / dm3 All other conditions stay the same Table 6.1 shows the time taken for each reaction to finish Table 6.1 concentration of hydrochloric acid in mol / dm3 time taken for the reaction to finish in s 200 100 150 (i) C omplete Table 6.1 by writing the concentrations of hydrochloric acid in the first column [1] (ii) D escribe the effect on the time taken for the zinc to finish reacting with 2.0 mol / dm3 hydrochloric acid with no catalyst present All other conditions stay the same [1] (iii) D escribe the effect on the time taken for the zinc to finish reacting with 2.0 mol / dm3 hydrochloric acid when the surface area of the zinc is increased All other conditions stay the same [1] (b) Crystals of zinc chloride can be prepared by reacting excess zinc with dilute hydrochloric acid Choose from the list, the method used to separate the unreacted zinc from the reaction mixture Draw a circle around your chosen answer © UCLES 2023 chromatography crystallisation 0620/31/M/J/23 evaporation filtration[1] 15 (iii) Aqueous ammonia is alkaline Choose from the list, the pH value that is alkaline Draw a circle around your chosen answer pH pH pH pH 10[1] (iv) Aqueous ammonia releases ammonia gas Ammonia gas turns damp red litmus paper blue A long glass tube is set up as shown in Fig. 8.2 long glass tube cotton wool soaked in aqueous ammonia damp red litmus paper Fig 8.2 At first, the litmus paper does not turn blue After a short time, the litmus paper turns blue Explain these results in terms of the kinetic particle theory [3] [Total: 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 To avoid the issue of disclosure of answer-related information to candidates, all copyright acknowledgements are reproduced online in the Cambridge Assessment International Education Copyright Acknowledgements Booklet This is produced for each series of examinations and is freely available to download at www.cambridgeinternational.org after the live examination series Cambridge Assessment International Education is part of Cambridge Assessment Cambridge Assessment is the brand name of the University of Cambridge Local Examinations Syndicate (UCLES), which is a department of the University of Cambridge © UCLES 2023 0620/31/M/J/23 © UCLES 2023 12 V Cr Mn Co 27 Ni 28 Cu 29 Zn 30 Fe 57–71 56 55 0620/31/M/J/23 104 88 – 90 89 232 thorium actinium – Th Ac 140 cerium 139 lanthanum 59 231 protactinium Pa 91 141 praseodymium Pr – 58 Ce – Db dubnium Rf rutherfordium La 57 actinoids 105 181 tantalum Ta 73 93 niobium Nb 41 51 vanadium 238 uranium U 92 144 neodymium 60 Nd – Sg seaborgium 106 184 tungsten W 74 96 molybdenum Mo 42 52 chromium – neptunium Np 93 – promethium 61 Pm – Bh bohrium 107 186 rhenium Re 75 – technetium Tc 43 55 manganese – plutonium Pu 94 150 samarium 62 Sm – Hs hassium 108 190 osmium Os 76 101 ruthenium Ru 44 56 iron – americium Am 95 152 europium 63 Eu – Mt meitnerium 109 192 iridium Ir 77 103 rhodium Rh 45 59 cobalt – curium Cm 96 157 gadolinium 64 Gd – Ds darmstadtium 110 195 platinum Pt 78 106 palladium Pd 46 59 nickel The volume of one mole of any gas is 24 dm3 at room temperature and pressure (r.t.p.) actinoids lanthanoids – Ra radium Fr francium 89–103 178 87 137 hafnium 133 barium Hf caesium lanthanoids Ba 72 91 zirconium Zr 40 48 titanium Cs 89 yttrium 88 strontium 85 rubidium Y 39 45 Sr 38 40 Ca Rb 37 39 K scandium – berkelium Bk 97 159 terbium 65 Tb – Rg roentgenium 111 gold 197 Au 79 108 silver Ag 47 64 copper – californium Cf 98 163 dysprosium 66 Dy – Cn copernicium 112 201 mercury Hg 80 112 cadmium Cd 48 65 zinc calcium Ti 26 potassium Sc 25 31 24 – einsteinium Es 99 165 holmium 67 Ho – Nh nihonium 113 204 thallium Tl 81 115 indium In 49 70 gallium Ga 27 20 24 19 23 aluminium Al 13 11 boron magnesium 23 sodium 22 B C N O VI F VII VIII – fermium Fm 100 167 erbium 68 Er – Fl flerovium 114 lead 207 Pb 82 tin 119 Sn 50 73 germanium Ge 32 28 silicon Si 14 12 carbon – mendelevium Md 101 169 thulium 69 Tm – Mc moscovium 115 209 bismuth Bi 83 122 antimony Sb 51 75 arsenic As 33 31 phosphorus P 15 14 nitrogen – nobelium No 102 173 ytterbium 70 Yb – Lv livermorium 116 – polonium Po 84 128 tellurium Te 52 79 selenium Se 34 32 sulfur S 16 16 oxygen – Lr lawrencium 103 175 lutetium 71 Lu – Ts tennessine 117 – astatine At 85 127 iodine I 53 80 bromine Br 35 35.5 chlorine Cl 17 19 fluorine – oganesson Og – 118 radon 86 Rn 131 xenon 54 Xe 84 krypton 36 Kr 40 argon 18 Ar 20 neon Ne 10 helium V hydrogen IV He Mg 21 relative atomic mass name atomic symbol atomic number Key III H Na 11 Be beryllium Li lithium II I Group The Periodic Table of Elements 16 Cambridge IGCSE™ CHEMISTRY 0620/31 Paper Theory (Core) May/June 2023 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 2023 series for most Cambridge IGCSE, Cambridge International A and AS Level and Cambridge Pre-U components, and some Cambridge O Level components This document consists of 13 printed pages © UCLES 2023 [Turn over 0620/31 Cambridge IGCSE – Mark Scheme PUBLISHED Generic Marking Principles May/June 2023 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 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 © UCLES 2023 Page of 13 0620/31 Cambridge IGCSE – Mark Scheme PUBLISHED May/June 2023 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 © UCLES 2023 Page of 13 0620/31 Cambridge IGCSE – Mark Scheme PUBLISHED May/June 2023 Science-Specific Marking Principles Examiners should consider the context and scientific use of any keywords when awarding marks Although keywords may be present, marks should not be awarded if the keywords are used incorrectly The examiner should not choose between contradictory statements given in the same question part, and credit should not be awarded for any correct statement that is contradicted within the same question part Wrong science that is irrelevant to the question should be ignored Although spellings not have to be correct, spellings of syllabus terms must allow for clear and unambiguous separation from other syllabus terms with which they may be confused (e.g ethane / ethene, glucagon / glycogen, refraction / reflection) The error carried forward (ecf) principle should be applied, where appropriate If an incorrect answer is subsequently used in a scientifically correct way, the candidate should be awarded these subsequent marking points Further guidance will be included in the mark scheme where necessary and any exceptions to this general principle will be noted ‘List rule’ guidance For questions that require n responses (e.g State two reasons …): The response should be read as continuous prose, even when numbered answer spaces are provided Any response marked ignore in the mark scheme should not count towards n Incorrect responses should not be awarded credit but will still count towards n Read the entire response to check for any responses that contradict those that would otherwise be credited Credit should not be awarded for any responses that are contradicted within the rest of the response Where two responses contradict one another, this should be treated as a single incorrect response Non-contradictory responses after the first n responses may be ignored even if they include incorrect science © UCLES 2023 Page of 13 0620/31 Cambridge IGCSE – Mark Scheme PUBLISHED May/June 2023 Calculation specific guidance Correct answers to calculations should be given full credit even if there is no working or incorrect working, unless the question states ‘show your working’ For questions in which the number of significant figures required is not stated, credit should be awarded for correct answers when rounded by the examiner to the number of significant figures given in the mark scheme This may not apply to measured values For answers given in standard form (e.g a 10n) in which the convention of restricting the value of the coefficient (a) to a value between and 10 is not followed, credit may still be awarded if the answer can be converted to the answer given in the mark scheme Unless a separate mark is given for a unit, a missing or incorrect unit will normally mean that the final calculation mark is not awarded Exceptions to this general principle will be noted in the mark scheme Guidance for chemical equations Multiples / fractions of coefficients used in chemical equations are acceptable unless stated otherwise in the mark scheme State symbols given in an equation should be ignored unless asked for in the question or stated otherwise in the mark scheme © UCLES 2023 Page of 13 0620/31 Cambridge IGCSE – Mark Scheme PUBLISHED Examples of how to apply the list rule State three reasons … [3] A Correct Correct Wrong B Correct, Correct (4 responses) Correct Wrong ignore C Correct (4 responses) Correct, Wrong , , Correct ignore D Correct (4 responses) Correct, CON (of 2.) Correct © UCLES 2023 , (discount 2) 2 Page of 13 May/June 2023 0620/31 Cambridge IGCSE – Mark Scheme PUBLISHED E Correct (4 responses) Correct Correct, Wrong F Correct (4 responses) Correct Correct CON (of 3.) Correct (5 responses) Correct ignore ignore H Correct (4 responses) Correct CON (of 2.) Correct Correct (4 responses) Correct © UCLES 2023 (discount 2) I Correct CON (of 2.) (discount 3) G Correct Correct CON (of 4.) (discount 2) Page of 13 May/June 2023 0620/31 Cambridge IGCSE – Mark Scheme PUBLISHED Question Answer May/June 2023 Marks 1(a) N 1(b) He 1(c) I 1(d) O 1(e) Fe 1(f) Al Question Answer Marks 2(a)(i) values between –100 °C and +58 °C (inclusive of these values) 2(a)(ii) values between 3.20 and 10.0 (inclusive of these values 2(a)(iii) gas –10 °C is above the boiling point 2(b)(i) displacement 2(b)(ii) chlorine is more reactive than iodine / iodine is less reactive than chlorine 2(c) configuration as 2,8,7 2(d) damp litmus paper (1) bleaches (1) © UCLES 2023 Page of 13 0620/31 Cambridge IGCSE – Mark Scheme PUBLISHED Question 3(a) Answer May/June 2023 Marks oxygen 3(b)(i) sewage / microbes 3(b)(ii) deoxygenate (the water) / remove oxygen (from the water) 3(c)(i) hydrogencarbonate 3(c)(ii) ammonium 3(c)(iii) 0.44 (mg) 3(d)(i) (substance that is) chemically combined with water 3(d)(ii) heat 2(H2O) (1) 3(e) H2 (1) Question 4(a) Answer atom(s) with the same number of protons(1) Marks different numbers of neutrons (1) 4(b) protons: 16 (1) neutrons: 20 (1) electrons: 18 (1) 4(c)(i) © UCLES 2023 S + O2 on left horizontal line AND SO2 on right horizontal line Page of 13 0620/31 Cambridge IGCSE – Mark Scheme PUBLISHED Question May/June 2023 Answer Marks 4(c)(ii) the energy of the reactants is greater than the energy of the product / the energy of S + O2 is greater than the energy of SO2 4(c)(iii) surroundings 4(d)(i) right hand electrode labelled cathode (1) electrolyte labelled (1) 4(d)(ii) product at positive electrode: oxygen (1) observations at positive electrode: bubbles (1) product at negative electrode: hydrogen (1) observations at negative electrode: bubbles (1) 4(e) sodium sulfate (1) carbon dioxide (1) water (1) 4(f) colourless Question 5(a) Answer mark each for any two of: © UCLES 2023 Marks iron has a high(er) melting point / boiling point iron has a high(er) density iron is strong(er) hard(er) Page 10 of 13 0620/31 Cambridge IGCSE – Mark Scheme PUBLISHED Question 5(b) Answer to provide heat / increase temperature (1) May/June 2023 Marks to produce carbon dioxide (from the combustion of carbon) (1) 5(c)(i) mixture of a metal with another element 5(c)(ii) harder / stronger / more resistant to corrosion lead