Chemistry 0620/33 May/June 2021: question paper and mark scheme

Question

(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 electronic structures. Each electronic structure may be used once, more than once or not at all. State which electronic structure, A, B, C, D or E, represents: (i) an atom of an element in Group VI of the Periodic Table . …… [1] (ii) an atom of a reactive metal . …… [1] (iii) an atom with a proton number of 17 . …… [1] (iv) an atom that forms a stable ion with a charge of 2– . …… [1] (v) an atom of oxygen. . …… [1] (b) Complete the table to show the number of electrons, neutrons and protons in the bromine atom and fluoride ion shown. number of number of number of electrons neutrons protons 35Br 81 35 9F 19 – 10 [3] [Total: 8]

Question

The table shows the masses of some of the ions in 1000 cm3 of fruit juice. mass of ion in 1000 cm3 name of ion formula of ion of fruit juice / mg ammonium NH4+ 6 calcium Ca2+ 73 chloride Cl – 238 magnesium Mg2+ 77 NO3– 10 phosphate PO43– 20 potassium K+ 419 Na+ 3 sulfate SO42– 10 (a) Answer these questions using only the information in the table. (i) State which negative ion has the highest mass in 1000 cm3 of fruit juice. . …… [1] (ii) Give the formulae of the ions in sodium nitrate. …… and . …… [1] (iii) Calculate the mass of ammonium ions in 250 cm3 of fruit juice. mass = …… mg [1] (b) Describe a test for chloride ions. test . …… observations …… [2] (c) Phosphate ions, PO43–, are present in most fertilisers. Phosphate ions contain phosphorus. (i) State the names of two other elements that are in most fertilisers. 1 . …… 2 . …… [2] (ii) Explain why farmers put fertilisers on fields where crops are to be grown. . …… . …… [1] (d) A student heated ammonium sulfate with sodium hydroxide in a test-tube. (i) Complete the equation for this reaction. (NH4)2SO4 + ……NaOH → ……NH3 + Na2SO4 + 2H2O [2] (ii) Concentrated aqueous ammonia releases fumes of ammonia gas. A long glass tube is set up as shown. long glass tube cotton wool soaked in damp red litmus paper concentrated aqueous ammonia At first, the red litmus paper does not turn blue. After a short time, the litmus paper turns blue. Explain these observations using the kinetic particle model. . …… . …… . …… . …… . …… [3] [Total: 13]

Question

The table shows some properties of five halogens. melting point boiling point density of liquid at element colour / °C / °C boiling point in g / cm3 fluorine –220 –188 yellow chlorine –35 1.56 light green bromine –7 59 3.12 red-brown iodine 114 184 4.93 dark grey astatine 302 337 6.35 (a) (i) Complete the table by predicting: ● the melting point of chlorine ● the density of liquid fluorine at its boiling point ● the colour of astatine. [3] (ii) Deduce the state of bromine at 0 °C. Explain your answer. . …… . …… . …… [2] (b) Complete the dot-and-cross diagram to show the electron arrangement in a molecule of chlorine. Show the outer shell electrons only. [2] (c) (i) Astatine is a radioactive element. 85 At, decays to form an isotope of bismuth, 83 Bi. An isotope of astatine, 217 213 Describe what happens to the number of nucleons during this decay. . …… [1] (ii) One of these statements about isotopes is incorrect. Tick the box with the incorrect statement. The isotope 235U is a source of energy. Some radioactive isotopes can be used to treat cancer. All isotopes are radioactive. Isotopes of the same element have the same number of protons. [1] [Total: 9]

Question

(a) The structure of two organic compounds, F and G, are shown. F G H H H H H H C C H C C H H H C C H C C H C C H C C H H H C C H C C H H H H H H H (i) Compound F is an unsaturated compound. Describe a chemical test for an unsaturated compound. test . …… observations …… [2] (ii) Compound F is reduced to compound G using hydrogen and a catalyst. State what is meant by the term catalyst. . …… . …… [1] (iii) Compound G is a saturated hydrocarbon. Name the saturated hydrocarbon which contains two carbon atoms. . …… [1] (b) Compound G is oxidised by nitric acid to compound H. The structure of compound H is shown. H O H H H H H H O C C C C C C C C H O H H H H H H O H (i) Deduce the formula of compound H to show the number of carbon, hydrogen and oxygen atoms. . …… [1] (ii) Compound H contains two carboxylic acid functional groups. Ethanoic acid also contains a carboxylic acid functional group. Draw the structure of ethanoic acid. Show all of the atoms and all of the bonds. [1] (iii) Describe the observations made when ethanoic acid reacts with: universal indicator solution …… sodium. …… [2] (c) A student’s graph of how the pH changes when aqueous ammonia is added slowly to dilute ethanoic acid is shown. 12 10 8 pH 6 4 2 0 0 10 20 30 40 volume of aqueous ammonia added / cm3 (i) Deduce the pH of the dilute ethanoic acid before the addition of aqueous ammonia. pH = …… [1] (ii) Deduce the volume of aqueous ammonia added when the pH is neutral. …… cm3 [1] (d) Compound H reacts with compound J to form a polymer. Compound J has the formula HOCH2CH2OH. (i) State the name of the –OH functional group in compound J. . …… [1] (ii) Ethene polymerises to form poly(ethene). Choose one word from the list that best describes the type of reaction that occurs. Draw a circle around the correct answer. addition combustion cracking reduction[1] [Total: 12]

Question

(a) Cement is made by heating a mixture of calcium carbonate and powdered clay. (i) Choose from the list the name of the substance which contains calcium carbonate. Draw a circle around the correct answer. bauxite hematite limestone slaked lime[1] (ii) The heat for this process is provided by burning natural gas. Name the main constituent of natural gas. . …… [1] (b) Complete the word equation for the thermal decomposition of calcium carbonate. calcium …… …… + carbonate [2] (c) Carbon dioxide is produced when dilute hydrochloric acid reacts with powdered calcium carbonate. CaCO3 + 2HCl → CaCl 2 + CO2 + H2O (i) Complete the diagram to show the apparatus used to investigate the volume of carbon dioxide produced during this reaction. M water [2] (ii) Name the piece of apparatus labelled M in the diagram. . …… [1] (iii) Suggest the name of another piece of apparatus that can be used to measure the volume of carbon dioxide produced. . …… [1] (iv) Describe the effect of each of the following on the rate of reaction of dilute hydrochloric acid with calcium carbonate. ● Large pieces of calcium carbonate are used instead of powdered calcium carbonate. All other conditions stay the same. . …… ● The temperature is decreased. All other conditions stay the same. . …… [2] (d) Explain how carbon dioxide contributes to climate change. …… [2] [Total: 12]

Question

This question is about air. (a) State the percentage of nitrogen in clean, dry air. …… % [1] (b) Clean, dry air also contains argon. Argon is unreactive. (i) Explain, using ideas about electronic structure, why argon is unreactive. . …… . …… [1] (ii) Give one use of argon. . …… [1] (c) Carbon monoxide and oxides of nitrogen are pollutants of air. For each of these pollutants state the source of the pollutant and an adverse effect of the pollutant. source of carbon monoxide …… adverse effect …… source of oxides of nitrogen …… adverse effect …… [4] [Total: 7]

Question

Concentrated hydrochloric acid is electrolysed using carbon electrodes. (a) State the products of this electrolysis at: the negative electrode …… the positive electrode. …… [2] (b) Name a metal that can be used as an inert electrode instead of carbon. …… [1] (c) When dilute sulfuric acid is electrolysed, oxygen is produced at the positive electrode. (i) Describe the separation and motion of the molecules in oxygen gas. separation . …… . …… motion . …… . …… [2] (ii) Describe a test for oxygen. test . …… observations …… [2] [Total: 7]

Question

This question is about elements in the Periodic Table. (a) The table shows some properties of five elements, P, Q, R, S and T. melting point density electrical conductivity atomic radius element / °C in g / cm3 of the solid / nm P 114 4.93 does not conduct 0.133 Q 1083 8.92 very good 0.117 R 3550 3.51 very good 0.077 S 1495 8.9 very good 0.121 T 248 1.2 does not conduct 0.065 Use only the elements shown in the table to answer these questions. State which two of the elements, P, Q, R, S and T, have covalent molecules. Give two reasons for your answer. elements …… and …… reason 1 …… reason 2 …… [3] (b) Diamond is a form of solid carbon. (i) Describe the structure and bonding in diamond. . …… . …… [2] (ii) State why diamond is used for cutting tools. . …… [1] (iii) Name one other form of solid carbon. . …… [1] (c) Lithium is an element in Group I of the Periodic Table. Copper is a transition element. Copper has a higher melting point and higher boiling point than lithium. Give two other ways in which the properties of transition elements differ from the properties of Group I elements. …… [2] (d) State whether lithium oxide is a basic oxide or an acidic oxide. Give a reason for your answer. …… [1] (e) The table compares the reactions of four metals with steam. metal reaction with steam copper does not react iron reacts rapidly at 120 °C lithium reacts very rapidly at 120 °C nickel only reacts above 800 °C Put the four metals in order of their reactivity. Put the least reactive metal first. least reactive most reactive [2] [Total: 12] 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 16 rubidium strontium yttrium zirconium niobium molybdenum technetium ruthenium rhodium palladium silver cadmium indium tin antimony tellurium iodine xenon 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.).