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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™ *7052172409* CHEMISTRY0620/42 May/June 2023 Paper Theory (Extended) 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 12 pages IB23 06_0620_42/3RP © UCLES 2023 [Turn over 1 A list of oxides, A to H, is shown A calcium oxide B aluminium oxide C silicon(IV) oxide D sulfur dioxide E carbon dioxide F iron(III) oxide G silver oxide H carbon monoxide Answer the following questions about the oxides, A to H Each letter may be used once, more than once or not at all State which of the oxides, A to H: (a) is responsible for acid rain ���������������������������������������������������������������������������������������������������������������������������������������������� [1] (b) has a giant covalent structure ���������������������������������������������������������������������������������������������������������������������������������������������� [1] (c) is a reducing agent in the blast furnace ���������������������������������������������������������������������������������������������������������������������������������������������� [1] (d) is the main constituent of bauxite ���������������������������������������������������������������������������������������������������������������������������������������������� [1] (e) is the main impurity in iron ore ���������������������������������������������������������������������������������������������������������������������������������������������� [1] (f) can be reduced by heating with copper ���������������������������������������������������������������������������������������������������������������������������������������������� [1] [Total: 6] © UCLES 2023 0620/42/M/J/23 2 Fluorine, chlorine and bromine are in Group VII of the Periodic Table (a) State the name given to Group VII elements [1] (b) Explain why Group VII elements have similar chemical properties [1] (c) Complete Table 2.1 to show the colour and state at r.t.p of some Group VII elements Table 2.1 element colour state at r.t.p fluorine pale yellow chlorine bromine liquid [3] (d) Bromine has two naturally occurring isotopes, 79Br and 81Br (i) State the term given to the numbers 79 and 81 in these isotopes of bromine [1] (ii) Complete Table 2.2 to show the number of protons, neutrons and electrons in the atom and ion of bromine shown Table 2.2 79 Br 81 Br – protons neutrons electrons [3] © UCLES 2023 0620/42/M/J/23 [Turn over (iii) Table 2.3 shows the relative abundances of the two naturally occurring isotopes of bromine Table 2.3 isotope 79 relative abundance Br 55% 81 Br 45% Calculate the relative atomic mass of bromine to one decimal place relative atomic mass = [2] (e) Chlorine displaces bromine from aqueous potassium bromide but does not displace fluorine from aqueous sodium fluoride (i) Write the symbol equation for the reaction between chlorine and aqueous potassium bromide [2] (ii) State why chlorine does not displace fluorine from aqueous sodium fluoride [1] (f) Aqueous silver nitrate is a colourless solution containing Ag+(aq) ions (i) Describe what is seen when aqueous silver nitrate is added to aqueous sodium chloride [1] (ii) Write the ionic equation for the reaction between aqueous silver nitrate and aqueous sodium chloride Include state symbols [3] [Total: 18] © UCLES 2023 0620/42/M/J/23 3 Over 200 million tonnes of sulfuric acid are manufactured every year (a) State the name of the process used to manufacture sulfuric acid [1] (b) Part of the manufacture of sulfuric acid involves converting sulfur dioxide to sulfur trioxide (i) Describe two methods by which sulfur dioxide is obtained 1 [2] The conversion of sulfur dioxide to sulfur trioxide is a reversible reaction which can reach equilibrium 2SO2(g) + O2(g) 2SO3(g) (ii) State two features of an equilibrium 1 [2] (iii) State the typical conditions and name the catalyst used in the conversion of sulfur dioxide to sulfur trioxide temperature °C pressure kPa catalyst [3] © UCLES 2023 0620/42/M/J/23 [Turn over (iv) Complete Table 3.1 to show the effect, if any, when the following changes are applied to the conversion of sulfur dioxide to sulfur trioxide 2SO2(g) + O2(g) 2SO3(g) The forward reaction is exothermic Only use the words increases, decreases or no change Table 3.1 change effect on the rate of the forward reaction temperature decreases decreases effect on the concentration of SO3(g) at equilibrium pressure increases no catalyst decreases [4] (v) Explain in terms of collision theory why reducing the temperature decreases the rate of the forward reaction [3] (c) Sulfuric acid contains SO42– ions The oxidation number of O atoms in SO42– ions is –2 Determine the oxidation number of S atoms in SO42– ions Show your working oxidation number = [2] [Total: 17] © UCLES 2023 0620/42/M/J/23 4 Solid sodium hydroxide is a base which dissolves to form an aqueous solution, NaOH(aq) (a) State what is meant by the term base [1] (b) State the term given to a base which dissolves to form an aqueous solution [1] (c) State the colour of thymolphthalein in NaOH(aq) [1] (d) Complete the word equation for the reaction of NaOH(aq) with ammonium chloride sodium hydroxide + ammonium chloride → + + [3] (e) Some metal oxides react with NaOH(aq) (i) State the term given to metal oxides which react with bases such as NaOH(aq) [1] (ii) Name a metal oxide which reacts with NaOH(aq) © UCLES 2023 [1] 0620/42/M/J/23 [Turn over (f) Ethanoic acid, CH3COOH, is a weak acid (i) Complete the dot-and-cross diagram in Fig. 4.1 of a molecule of ethanoic acid O H H C C H O H Fig 4.1 [3] (ii) Suggest the pH of dilute ethanoic acid [1] (iii) Complete the symbol equation to show the dissociation of ethanoic acid CH3COOH [3] (iv) Write the ionic equation for the reaction when an acid neutralises a soluble base © UCLES 2023 [1] 0620/42/M/J/23 (g) In a titration, 25.0 cm3 of 0.0800 mol / dm3 aqueous potassium hydroxide, KOH(aq), is neutralised by 20.0 cm3 of dilute sulfuric acid, H2SO4(aq) 2KOH(aq) + H2SO4(aq) → K2SO4(aq) + 2H2O(l) Calculate the concentration of H2SO4, in g / dm3 using the following steps ● Calculate the number of moles of KOH used mol ● Determine the number of moles of H2SO4 which react with the KOH mol ● Calculate the concentration of H2SO4 in mol / dm3 mol / dm3 ● Calculate the concentration of H2SO4 in g / dm3 g / dm3 [5] © UCLES 2023 [Total: 21] 0620/42/M/J/23 [Turn over 10 5 Propane and propene both react with chlorine (a) When a molecule of propane, C3H8, reacts with chlorine in the presence of ultraviolet light, one atom of hydrogen is replaced by one atom of chlorine (i) State the term given to reactions in which one atom in an alkane is replaced by another atom [1] (ii) State the purpose of ultraviolet light in this reaction [1] (iii) State the term given to any reaction which requires ultraviolet light [1] (iv) Write the symbol equation for the reaction between propane and chlorine [2] (b) A molecule of propene, C3H6, is unsaturated and will react with chlorine at room temperature (i) State why propene is an unsaturated molecule [1] (ii) Give the structural formula of the product of this reaction [1] (c) Propene undergoes addition reactions with steam There are two possible products, A and B Draw the displayed formula and name each product displayed formula of product A name of product A displayed formula of product B name of product B [4] © UCLES 2023 [Total: 11] 0620/42/M/J/23 11 6 Carboxylic acids can be converted to esters (a) Name the ester formed when butanoic acid, CH3CH2CH2COOH, reacts with ethanol, CH3CH2OH [1] (b) Identify the other product formed in this reaction [1] (c) Deduce the empirical formula of the ester formed [1] (d) PET is a polyester Part of the structure of PET is shown in Fig. 6.1 O O C C O O O O C C O O Fig 6.1 (i) Circle one repeat unit of this polymer. (ii) Draw the structures of the monomers which make up PET Draw the functional groups using displayed formulae [1] [2] (iii) State the type of polymerisation used in making PET [1] [Total: 7] 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 0620/42/M/J/23 © UCLES 2023 12 V Cr Mn Co 27 Ni 28 Cu 29 Zn 30 Fe 57–71 56 55 0620/42/M/J/23 – 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 Ta tantalum 73 93 niobium Nb 41 51 vanadium 238 uranium U 92 144 neodymium 60 Nd – Sg seaborgium 106 184 W tungsten 74 96 molybdenum Mo 42 52 chromium – neptunium Np 93 – promethium 61 Pm – Bh bohrium 107 186 Re rhenium 75 – technetium Tc 43 55 manganese – plutonium Pu 94 150 samarium 62 Sm – Hs hassium 108 190 Os osmium 76 101 ruthenium Ru 44 56 iron – americium Am 95 152 europium 63 Eu – Mt meitnerium 109 192 Ir iridium 77 103 rhodium Rh 45 59 cobalt – curium Cm 96 157 gadolinium 64 Gd – Ds darmstadtium 110 195 Pt platinum 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 89–103 178 104 137 88 133 87 Hf hafnium Ba barium lanthanoids Cs 72 91 zirconium Zr 40 48 titanium caesium 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 111 197 gold Au 79 108 silver Ag 47 64 copper – californium Cf 98 163 dysprosium 66 Dy – Cn copernicium 112 201 Hg mercury 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 Tl thallium 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 114 207 lead 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 Bi bismuth 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 – Po polonium 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 – At astatine 85 127 iodine I 53 80 bromine Br 35 35.5 chlorine Cl 17 19 fluorine – Og oganesson 118 – Rn radon 86 131 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 Group Na 11 Be beryllium Li lithium II I The Periodic Table of Elements 12 Cambridge IGCSE™ CHEMISTRY 0620/42 Paper Theory (Extended) 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 10 printed pages © UCLES 2023 [Turn over 0620/42 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 10 0620/42 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 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 10 0620/42 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 10 0620/42 Cambridge IGCSE – Mark Scheme PUBLISHED Check the page above Q1(a) and assuming no relevant work is there, place ‘SEEN’ on the page For equations, allow multiples (including fractions); ignore state symbols except Q2(f)(ii) Question Answer May/June 2023 Marks 1(a) D 1(b) C 1(c) H 1(d) B 1(e) C 1(f) G Question Answer Marks 2(a) halogen(s) 2(b) same number of outer shell electrons 2(c) gas M1 pale yellow-green gas M2 red-brown M3 both gases 2(d)(i) © UCLES 2023 nucleon number / mass number Page of 10 0620/42 Cambridge IGCSE – Mark Scheme PUBLISHED Question Answer 2(d)(ii) 79Br 81Br– protons 35 35 neutrons 44 46 electrons 35 36 May/June 2023 Marks Each row ✔ 2(d)(iii) M1 79 55(%) + 81 45(%) M2 7990 / 100 = 79.9 2(e)(i) Cl2 + 2KBr 2KCl + Br2 M1 KCl as product M2 correct equation 2(e)(ii) chlorine less reactive than fluorine 2(f)(i) white precipitate 2(f)(ii) Ag+(aq) + Cl –(aq) AgCl(s) M1 AgCl as only product M2 Ag+ + Cl – as only reactants (in 1 : 1 ratio) M3 state symbols © UCLES 2023 Page of 10 0620/42 Cambridge IGCSE – Mark Scheme PUBLISHED Question Answer May/June 2023 Marks 3(a) contact (process) 3(b(i) M1 burning sulfur (in air) M2 Roasting sulfide ores (in air) 3(b)(ii) M1 the rate of forward reaction equals (the rate of the) reverse reaction M2 concentrations of reactants and products are constant 3(b)(iii) 450 (oC) 200 (kPa) vanadium(V) oxide 3(b)(iv) increases increases increase no change 3(b)(v) M1 kinetic energy of particles decreases M2 frequency of collisions between particles decreases M3 lower percentage / proportion / fraction of collisions / particles have energy greater than / qual to activation energy OR fewer of the collisions / particles have energy greater than / equal to activation energy 3(c) © UCLES 2023 M1 2 or 8 M2 S + (4 –2) = –2 ∴ S = + Page of 10 0620/42 Cambridge IGCSE – Mark Scheme PUBLISHED Question Answer May/June 2023 Marks 4(a) proton acceptor 4(b) alkali 4(c) blue 4(d) M1 sodium chloride M2 water M3 ammonia 4(e)(i) amphoteric (oxides) 4(e)(ii) aluminium oxide or zinc oxide 4(f)(i) M1 all single bonding dot and cross pairs correct M2 double C = O bond dot and cross pairs are correct M3 complete diagram is correct 4(f)(ii) 3≤ pH < 4(f)(iii)i CH3COOH ⇌ CH3COO– + H+ M1 H+ M2 CH3COO– M3 use of ⇌ 4(f)(iv) H+ + OH– H2O © UCLES 2023 Page of 10 0620/42 Cambridge IGCSE – Mark Scheme PUBLISHED Question 4(g) Answer M1 mol KOH = 0.0800 25 / 1000 = 0.002(00) / 2(00) 10–3 May/June 2023 Marks M2 mol H2SO4 = M1 / 2 = 0.002 / 2 = 0.001(00) / 1(00 10–3 M3 = M2 1000 / 20 = 0.001 1000 / 20 = 0.05(00) / 5.(00) 10–2 M4 = 98 M5 = 98 M3 = 98 0.05(00) = 4.9(0) (g / dm3) Question Answer Marks 5(a)(i) substitution 5(a)(ii) provide activation energy 5(a)(iii) photochemical 5(a)(iv) C3H8 + Cl2 C3H7Cl + HCl M1 HCl M2 equation correct 5(b)(i) it has a carbon-carbon bond which is not a single bond 5(b)(ii) CH3CHClCH2Cl © UCLES 2023 Page of 10 0620/42 Cambridge IGCSE – Mark Scheme PUBLISHED Question 5(c) Answer May/June 2023 Marks M1 displayed formula of propan-1-ol M2 displayed formula of propan-2-ol M3 propan-1-ol (as either name) M4 propan-2-ol (under displayed formula of propan-2-ol) Question Answer Marks 6(a) ethyl butanoate 6(b) water 6(c) C3H6O 6(d)(i) repeat unit circled 6(d)(ii) M1 displayed diol on correct box (unshaded) M2 displayed dioic acid on correct box (shaded) 6(d)(iii) © UCLES 2023 condensation Page 10 of 10