Chemistry 0620/43 May/June 2020: question paper and mark scheme

Question

(a) The structures of five organic compounds, A, B, C, D and E, are shown. Answer the questions that follow. Each letter may be used once, more than once or not at all. A B C H H H H O H H H H H C H C C C C H C C C H H C C H H H O H H H H H H D E H H H H H O H C C C O H H C C C H H H H H O H (i) Give the letter of the compound that is propan-1-ol. . …… [1] (ii) Give the letter of the compound that has the empirical formula CH2. . …… [1] (iii) Give the letter of one compound that reacts with bromine in an addition reaction. . …… [1] (iv) Give the letter of one compound that reacts with chlorine to form the compound shown. H Cl H H C C C H H H H . …… [1] (v) Give the letters of two compounds that can react with each other to form an ester. (vi) Give the letter of the compound that is in the same homologous series as hex‑1‑ene. . …… [1] (vii) Give the letter of one compound that is an acid. . …… [1] (viii) Draw a structural isomer of compound D. Show all of the atoms and all of the bonds. [1] (b) Some acids are described as weak acids. State the meaning of the term weak acid. weak …… acid …… [2] [Total: 10]

Question

Ammonia is manufactured by the Haber process. (a) The equation for the reaction is shown. N2(g) + 3H2(g) 2NH3(g) (i) State what is meant by the symbol . . …… [1] (ii) State one source of hydrogen used in the manufacture of ammonia. . …… [1] (b) The table shows some data for the production of ammonia. pressure temperature percentage yield / atm / °C of ammonia 250 350 58 100 450 28 400 450 42 250 550 20 Deduce the effect on the percentage yield of ammonia of: ●● increasing the pressure of the reaction ●● increasing the temperature of the reaction. [2] (c) Explain, in terms of particles, what happens to the rate of this reaction when the temperature is increased. …… [3] (d) Ammonia, NH3, is used to produce nitric acid, HNO3. This happens in a three-stage process. Stage 1 is a redox reaction. 4NH3 + 5O2 → 4NO + 6H2O (i) Identify what is oxidised in stage 1. Give a reason for your answer. substance oxidised …… reason . …… . …… [2] (ii) In this reaction the predicted yield of NO is 512 g. The actual yield is 384 g. Calculate the percentage yield of NO in this reaction. percentage yield of NO = …… [1] (iii) The equation for the reaction in stage 2 is shown. 2NO + O2 → 2NO2 Which major environmental problem does NO2 cause if it is released into the atmosphere? . …… . …… [1] (iv) The equation for the reaction in stage 3 is shown. 4NO2 + 2H2O + O2 → 4HNO3 Calculate the volume of O2 gas, at room temperature and pressure (r.t.p.), needed to produce 1260 g of HNO3. Use the following steps. ●● Calculate the number of moles of HNO3. moles of HNO3 = …… ●● Deduce the number of moles of O2 that reacted. moles of O2 = …… ●● Calculate the volume of O2 gas that reacts at room temperature and pressure (r.t.p.). volume of O2 gas = …… dm3 [4] (e) The reaction in stage 3 is exothermic. 4NO2 + 2H2O + O2 → 4HNO3 Complete the energy level diagram for this reaction. Include an arrow that clearly shows the energy change during the reaction. 4NO2 + 2H2O + O2 energy progress of reaction [3] [Total: 18]

Question

Chlorine is in Group VII of the Periodic Table. (a) Two isotopes of chlorine are chlorine‑35 and chlorine‑37. (i) State why these two isotopes of chlorine have the same chemical properties. . …… . …… . …… [2] (ii) Complete the table to show the number of electrons, neutrons and protons in each atom and ion. number of number of number of electrons neutrons protons 17Cl 35 17Cl 37 – [3] (b) (i) Chlorine reacts with aqueous sodium bromide. The equation for the reaction is shown. Cl 2 + 2NaBr → 2NaCl + Br2 State the type of reaction shown. . …… [1] (ii) Why is there no reaction between iodine and aqueous sodium bromide? . …… [1] (c) Magnesium reacts with chlorine to form magnesium chloride. Complete the dot-and-cross diagram to show the electron arrangement of the ions in magnesium chloride. Give the charges on the ions. The inner shells have been completed. Mg Cl [3] (d) Hydrogen and chlorine react to form hydrogen chloride gas, as shown in the equation. H2 + Cl 2 → 2HCl This equation can be represented as shown. H–H + Cl –Cl → 2H–Cl Some bond energies are shown in the table. bond energy bond in kJ / mol H–H 436 Cl –Cl 243 H–Cl 432 Calculate the energy change for the reaction between hydrogen and chlorine, using the following steps. ●● Calculate the energy needed to break the bonds. …… kJ ●● Calculate the energy released when bonds are formed. …… kJ ●● Calculate the energy change for the reaction. …… kJ / mol [3] [Total: 13]

Question

(a) Filtration and chlorination are two stages in water treatment. State the purpose of each stage. filtration …… chlorination …… [2] (b) A student uses anhydrous copper(II) sulfate to test for the presence of water. (i) What colour change is seen if water is present? (ii) The purity of a sample of water can be assessed by measuring its boiling point. How is the boiling point of water affected by impurities? . …… [1] (c) Chromatography can be used to test the purity of substances. The diagram shows the chromatogram of a coloured substance. solvent front X start line (i) How does this chromatogram show that this substance is not pure? . …… [1] (ii) Draw a circle round the correct Rf value for the spot labelled X. 0.2 0.4 0.8 1.2 [1] (iii) State how a colourless substance can be made visible on a chromatogram. . …… [1] [Total: 8]

Question

(a) Complete the table about solids, liquids and gases. particle particle type of separation arrangement motion solid regular vibrate only liquid touching random gas apart random [3] (b) The graph shows the change in temperature as a sample of a gas is cooled. A B temperature time Name the change of state taking place between A and B. …… [1] (c) A bottle of liquid perfume is left open at the front of a room. After some time, the perfume is smelt at the back of the room. Name the two physical processes taking place. 1 …… 2 …… [2] [Total: 6]

Question

(a) An endothermic reaction occurs when calcium nitrate is heated. (i) Balance the equation for this reaction. ……Ca(NO3)2 → ……CaO + ……NO2 + ……O2 [1] (ii) State the type of reaction shown by the equation. . …… [1] (b) Describe the test for a nitrate ion. test . …… result . …… [3] [Total: 5]

Question

Aluminium is extracted by electrolysis. Iron is extracted from its ore by reduction with carbon. (a) What is meant by the term electrolysis? …… [2] (b) Name the main ore of aluminium. …… [1] (c) (i) Explain why aluminium cannot be extracted by reduction with carbon. . …… [1] (ii) Describe the role of cryolite in the extraction of aluminium by electrolysis. . …… [1] (iii) Name the product formed at the positive electrode. . …… [1] (iv) Write the ionic half-equation for the reaction at the negative electrode. . …… [2] (d) Aluminium is used in overhead electricity cables. Give two properties of aluminium that make it suitable for use in overhead electricity cables. 1 …… 2 …… [2] (e) Iron is a transition element. (i) Iron forms hydrated iron(III) oxide when it rusts. Write a word equation to represent the formation of rust. . …… [2] (ii) Give two ways in which the properties of transition elements differ from the properties of Group I metals. 1 . …… 2 . …… [2] [Total: 14]

Question

(a) Part of the synthetic polymer, nylon, is shown in the diagram. O O O O O C C N N C C N N C H H H H (i) Circle one amide linkage on the diagram. [1] (ii) Complete the structures of the two monomers that react to form nylon. [2] (iii) Name the other product formed when nylon is produced. . …… [1] (b) Items made from nylon are often disposed of by burying them in the ground. This is called landfill. Why is the disposal of nylon using landfill a problem? …… [1] (c) Give the name of a natural polymer. …… [1] [Total: 6] 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.).