Chemistry 0620/13 October/November 2020: question paper and mark scheme

Question

‘The movement of a substance very slowly from an area of high concentration to an area of low concentration.’ Which process is being described? A a liquid being frozen B a solid melting C a substance diffusing through a liquid D a substance diffusing through the air

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When a dark grey solid element is heated, it changes directly into a purple gas. Which word describes this change? A boiling B evaporation C melting D sublimation

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Nickel(II) sulfate is a green solid that is soluble in water. Which method is used to obtain a pure sample of nickel(II) sulfate crystals from a mixture of nickel(II) sulfate and sand? A Heat the mixture with water and distil it to give nickel(II) sulfate. B Heat the mixture with water and leave it to crystallise. C Heat the mixture with water and filter off the nickel(II) sulfate. D Heat the mixture with water, filter and allow the solution to crystallise.

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In the chromatography experiment shown, which label represents the solvent front? A B D C

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What is the meaning of the term nucleon number? A the number of neutrons in the nucleus of an atom B the number of protons in the nucleus of an atom C the total number of protons and electrons in the nucleus of an atom D the total number of protons and neutrons in the nucleus of an atom

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The diagram represents the structure of a solid. What could the solid be? brass graphite sodium chloride A B C D

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Magnesium reacts with sulfuric acid. What are the formulae of the products formed in this reaction? A MgSO4 and H2 B MgSO4 and H2O C Mg(SO4)2 and H2 D Mg(SO4)2 and H2O

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Which diagram shows the arrangement of the outer shell electrons in a molecule of water? A B H H H H O O C D H H H H O O

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Rubidium is in Group I of the Periodic Table and bromine is in Group VII. Rubidium reacts with bromine to form an ionic compound. Which row shows the electron change taking place for rubidium and the correct formula of the rubidium ion? electron change formula of ion formed A electron gained Rb+ B electron gained Rb– C electron lost Rb+ D electron lost Rb–

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Which statement explains why graphite is used as a lubricant? A All bonds between the atoms are weak. B It conducts electricity. C It has a low melting point. D Layers in the structure can slide over each other.

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The relative atomic mass of chlorine is 35.5. When calculating relative atomic mass, which particle is the mass of a chlorine atom compared to? A a neutron B a proton C an atom of carbon-12 D an atom of hydrogen-1

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Molten sodium chloride is electrolysed using inert electrodes. Which row shows the products formed at the cathode and anode? cathode anode A chlorine hydrogen B chlorine sodium C hydrogen chlorine D sodium chlorine

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Ethanol is used as a fuel. ethanol + oxygen → carbon dioxide + water Which statements are correct? 1 The reaction is endothermic. 2 The products have more energy than the reactants. 3 The oxygen for this reaction comes from the air. 4 The temperature of the reaction mixture rises during this reaction. A 1 and 2 B 1 and 3 C 2 and 4 D 3 and 4

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Hydrogen and the isotope uranium-235 are both used to generate electricity. Which term describes the change that occurs for both substances in this context? A combustion B endothermic C exothermic D decomposition

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Which substance does not require oxygen in order to produce energy? A coal B hydrogen C natural gas 235 D U

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When calcium carbonate reacts with dilute hydrochloric acid, carbon dioxide gas is given off. This causes the reaction mixture to lose mass. Four separate experiments are performed. The starting mass, and the mass after five minutes, are measured for each reaction mixture. In which experiment is carbon dioxide produced at the greatest rate? starting mass after mass / g five minutes / g A 14.37 11.89 B 16.52 15.29 C 16.76 14.12 D 16.99 15.21

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Silver oxide reacts with magnesium to make silver and magnesium oxide. Ag2O + Mg → 2Ag + MgO Which substance is oxidised in this reaction? A magnesium B magnesium oxide C silver D silver oxide

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When pink crystals of cobalt(II) chloride are heated, steam is given off and the colour of the solid changes to blue. CoCl 2•6H2O CoCl 2 + 6H2O What happens when water is added to the blue solid? colour temperature A changes to pink decreases B changes to pink increases C remains blue decreases D remains blue increases

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Which oxide is used to neutralise acidic gases in a power station? A calcium oxide B carbon dioxide C nitrogen oxide D sulfur dioxide

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Period 3 of the Periodic Table contains the elements sodium to argon. Element Q is a non-metal from this period. Which statement about Q is correct? A It conducts electricity. B It has a lower proton number than sodium. C It has electrons in only three shells. D It is malleable.

Question

Equal masses of a solid, X, are added in turn to an aqueous solution, Y. The pH of the solution is measured after each addition until the pH becomes 7. The readings are plotted as shown. 12 pH 7 2 0 1 2 3 4 5 6 additions of X What are X and Y? X Y A Cu(s) HCl (aq) B Mg(s) HCl (aq) C NH4Cl (s) NaOH(aq) D Zn(OH)2(s) NaOH(aq)

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An aqueous cation reacts with aqueous sodium hydroxide to form a white precipitate. The precipitate is insoluble in excess sodium hydroxide. What is the aqueous cation? A aluminium ion B calcium ion C chromium ion D zinc ion

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Vinegar has a pH of 3. Which statement about vinegar is correct? A It forms a salt with sulfuric acid. B It reacts with some metals to form hydrogen gas. C It reacts with ammonium compounds to give ammonia gas. D It turns red litmus blue.

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A student carries out an experiment to prepare pure magnesium sulfate crystals. The diagram shows the first stage of the preparation. stirrer magnesium carbonate dilute sulfuric acid He adds magnesium carbonate until no more reacts. Which process should he use for the next stage? A crystallisation B evaporation C filtration D neutralisation

Question

Which statement about the halogens and their compounds is correct? A The colour of the element gets lighter going down Group VII. B The elements get less dense going down Group VII. C When chlorine is added to sodium iodide solution, iodine is formed. D When iodine is added to sodium bromide solution, bromine is formed.

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Which compound contains a transition metal ion and a halide ion? A aluminium iodide B calcium fluoride C iron(III) oxide D nickel(II) chloride

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A flammable gas needs to be removed from a tank at an industrial plant. For safety reasons, an inert gas is used. Which gas is suitable? A argon B hydrogen C methane D oxygen

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A substance, X, has the following properties. 1 It has a high melting point. 2 It conducts electricity in the solid and liquid states. 3 It is malleable. 4 It has a high density. What is X? A a ceramic B copper C graphite D sodium chloride

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A metal M is between sodium and magnesium in the reactivity series. Which reactions occur with M and its oxide? M can be extracted M reacts by heating its oxide with steam with carbon A no no B no yes C yes no D yes yes

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Mild steel and stainless steel are two alloys containing the element iron. Which row identifies a use of each alloy? a use of mild steel a use of stainless steel A car bodies cutlery B car bodies electrical wiring C food containers cutlery D food containers electrical wiring

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Coke (carbon) and limestone are two raw materials used in the extraction of iron from hematite. Which type of reaction occurs when each substance is heated during the process? coke limestone A redox redox B redox thermal decomposition C thermal decomposition redox D thermal decomposition thermal decomposition

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Oxides of nitrogen are given out from car exhausts. Which row best shows why oxides of nitrogen are unwanted in the atmosphere? acidic toxic A no no B no yes C yes no D yes yes

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Two reactions, P and Q, produce carbon dioxide. P Q C6H12O6 CO2 Na2CO3 glucose sodium carbonate Which types of reaction are P and Q? P Q A neutralisation neutralisation B neutralisation respiration C respiration neutralisation D respiration respiration

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Which gas is used as a food preservative? A methane B fluorine C oxygen D sulfur dioxide

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Which calcium compound does not neutralise an acid soil? A calcium oxide B calcium sulfate C calcium hydroxide D calcium carbonate

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Petroleum is separated into fractions by fractional distillation. Separation occurs in a fractionating column. Some properties of three of these fractions are shown. number of boiling point fraction carbon atoms in range / °C the molecules 1 5 –10 2 320–350 16–24 3 120–210 Which statement is correct? A Fraction 1 has a higher boiling point range than fraction 2. B Fraction 2 is removed from a higher point in the fractionating column than fraction 1. C Molecules in fraction 3 have shorter chains than those in fraction 2. D None of the fractions are liquid at room temperature.

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How many atoms are there in one molecule of ethanoic acid? A 5 B 6 C 8 D 11

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The flow chart shows the preparation of ethanol and some important chemistry of ethanol. fermentation process Y substance X ethanol carbon dioxide + substance Z What are X, Y and Z? X Y Z A yeast combustion oxygen B glucose combustion steam C glucose polymerisation water D yeast fermentation glucose

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Which substance is not a fraction obtained from the fractional distillation of petroleum? A ethene B fuel oil C naphtha D refinery gas

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Some plastics are non-biodegradable. What is the meaning of the term non-biodegradable? A cannot be recycled for further use B gives off greenhouse gases when burnt C harmful to animals and plants D not broken down by natural processes The Periodic Table of Elements Group I II III IV V VI VII VIII 1 2 H He hydrogen helium Key 1 4 3 4 atomic number 5 6 7 8 9 10 Li Be atomic symbol B C N O F Ne lithium beryllium name boron carbon nitrogen oxygen fluorine neon 7 9 relative atomic mass 11 12 14 16 19 20 11 12 13 14 15 16 17 18 Na Mg Al Si P S Cl Ar sodium magnesium aluminium silicon phosphorus sulfur chlorine argon 23 24 27 28 31 32 35.5 40 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr potassium calcium scandium titanium vanadium chromium manganese iron cobalt nickel copper zinc gallium germanium arsenic selenium bromine krypton 39 40 45 48 51 52 55 56 59 59 64 65 70 73 75 79 80 84 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe rubidium strontium yttrium zirconium niobium molybdenum technetium ruthenium rhodium palladium silver cadmium indium tin antimony tellurium iodine xenon 16 85 88 89 91 93 96 – 101 103 106 108 112 115 119 122 128 127 131 55 56 57–71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 lanthanoids Cs Ba Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn caesium barium hafnium tantalum tungsten rhenium osmium iridium platinum gold mercury thallium lead bismuth polonium astatine radon 133 137 178 181 184 186 190 192 195 197 201 204 207 209 – – – 87 88 89–103 104 105 106 107 108 109 110 111 112 114 116 actinoids Fr Ra Rf Db Sg Bh Hs Mt Ds Rg Cn Fl Lv francium radium rutherfordium dubnium seaborgium bohrium hassium meitnerium darmstadtium roentgenium copernicium flerovium livermorium – – – – – – – – – – – – – 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 lanthanoids La Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu lanthanum cerium praseodymium neodymium promethium samarium europium gadolinium terbium dysprosium holmium erbium thulium ytterbium lutetium 139 140 141 144 – 150 152 157 159 163 165 167 169 173 175 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 actinoids Ac Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr actinium thorium protactinium uranium neptunium plutonium americium curium berkelium californium einsteinium fermium mendelevium nobelium lawrencium – 232 231 238 – – – – – – – – – – – The volume of one mole of any gas is 24 dm3 at room temperature and pressure (r.t.p.).