Chemistry 0620/32 May/June 2019: question paper and mark scheme

Question

The diagrams show part of the structures of five substances, A, B, C, D and E. S O Fe Fe Fe Fe H O O S Fe Fe Fe Fe H C O H S O O Fe Fe Fe Fe H O Fe Fe Fe Fe A B C O2– Ca2+ O2– H H Ca2+ O2– Ca2+ C C H H O2– Ca2+ O2– D E (a) Answer the following questions about these structures. Each structure may be used once, more than once or not at all. State which one of these structures, A, B, C, D or E: (i) is an alcohol . …… [1] (ii) is an ionic compound . …… [1] (iii) conducts electricity when solid . …… [1] (iv) contributes to acid rain . …… [1] (v) reacts with an acid to form a salt and water. . …… [1] (b) Substance E is a compound. What is meant by the term compound ? . …… . …… [1] [Total: 6]

Question

This question is about iron and compounds of iron. (a) Iron can be converted into steel in a basic oxygen converter. Oxygen is blown into the impure molten iron to remove some of the impurities. (i) Oxygen reacts with the carbon in the impure iron to form carbon dioxide. Write a chemical equation for this reaction. . …… [2] (ii) Basic oxides in the lining of the converter react with impurities such as sulfur dioxide to form slag. What type of oxide is sulfur dioxide? Give a reason for your answer. . …… . …… [2] (b) Iron(III) chloride, Fe2Cl 6, is produced when iron is heated with chlorine. The diagram shows the apparatus used. (i) Draw an arrow on the diagram to show where the apparatus is heated. iron wire in a ceramic boat flask iron(III) chloride collects here dry chlorine drying agent [1] (ii) Iron(III) chloride undergoes sublimation. What is meant by the term sublimation ? . …… . …… [1] (iii) Suggest why the iron(III) chloride is collected in the flask and not in the ceramic boat. . …… . …… [2] (iv) At higher temperatures, iron(III) chloride decomposes. heat Fe2Cl 6 2FeCl 2 + Cl 2 Explain why this is a decomposition reaction. . …… . …… [1] (c) Iron reacts with chlorine and other halogens. Name two other substances which react with iron. 1 . …… 2 . …… [2] (d) Describe a test for iron(II) ions. test . …… observations …… [2] [Total: 13]

Question

(a) The table shows the percentage by mass of the elements in the Earth’s crust and in the oceans. percentage by mass percentage by mass element in the Earth’s crust in the oceans aluminium 8.20 0.00 calcium 3.60 0.05 chlorine 0.05 1.80 hydrogen 0.22 11.00 iron 5.00 0.00 oxygen 46.60 85.80 silicon 29.50 0.00 sodium 2.80 1.15 other elements 4.03 total 100.00 100.00 Answer these questions using only the information in the table. (i) Deduce the percentage by mass of other elements present in the oceans. …… % [1] (ii) Which element is present in the Earth’s crust in the greatest percentage by mass? . …… [1] (iii) Give two major differences in the percentage by mass of the elements in the Earth’s crust and in the oceans. 1 . …… . …… 2 . …… . …… [2] (b) Aluminium oxide is a compound present in aluminium ore. (i) Name an ore which contains aluminium oxide. . …… [1] (ii) Predict the products of the electrolysis of molten aluminium oxide at: the positive electrode . …… the negative electrode. …… [2] (iii) Suggest why aluminium is extracted by electrolysis and not by reduction with carbon. . …… [1] [Total: 8]

Question

This question is about bromine and compounds of bromine. (a) Use the kinetic particle model to describe the arrangement and type of motion of the molecules in: ● liquid bromine …… . …… ● bromine gas. . …… . …… [4] (b) The graph shows how the volume of bromine gas changes with temperature. The pressure is kept constant. volume of bromine gas temperature Describe how the volume of the bromine gas changes with temperature. . …… . …… [1] (c) (i) Complete the word equation to show the halogen and halide compound which react to form the products bromine and potassium chloride. …… …… potassium + bromine + chloride [2] (ii) Explain, in terms of the reactivity of the halogens, why aqueous bromine will not react with aqueous potassium chloride. . …… . …… [1] (d) Bromine reacts with hydrogen sulfide, H2S. (i) Complete the chemical equation for this reaction. …… + H2S ……HBr + S [2] (ii) The energy level diagram for this reaction is shown. reactants energy products progress of reaction Explain how this diagram shows that the reaction is exothermic. . …… . …… [1] (e) Describe a test for bromide ions. test . …… observations …… [2] [Total: 13]

Question

Methane, ethane and ethene are hydrocarbons. (a) Draw the structure of a molecule of ethane. Show all of the atoms and all of the bonds. [1] (b) Which one of these compounds belongs to the same homologous series as methane? Draw a circle around the correct answer. butane methanoic acid methanol propene [1] (c) Ethene can be manufactured by cracking. (i) Complete the sentence about cracking using words from the list. atoms ions larger molecules reactive smaller Cracking is the process of breaking down …… alkane …… into …… alkanes and alkenes. [2] (ii) State two conditions needed for cracking. 1 . …… 2 . …… [2] (d) Poly(ethene) is made by the polymerisation of ethene. Which one of the structures represents part of a poly(ethene) molecule? Tick one box. CH3 H H H H H H H H H CH3 H CH3 H C C C C C C C C C C C C C C C C H H CH3 H H H H H H H H OH H OH [1] (e) Nylon is also a polymer. (i) Give one common use of nylon. . …… [1] (ii) Part of the structure of nylon is shown. H H H N (CH2)6 N C (CH2)4 C N O O How many different types of atom are shown in this structure? . …… [1] (f) The structure of a monomer used to make a polymer is shown. O H O C C C CH3 H H (i) What structural feature of this molecule shows that it is unsaturated? . …… [1] (ii) Describe a test to show that this compound is unsaturated. test . …… observations …… [2] [Total: 12]

Question

This question is about cobalt and compounds of cobalt. (a) Describe how you could prepare a pure sample of crystals of hydrated cobalt(II) sulfate using dilute sulfuric acid and an excess of cobalt(II) carbonate. . …… . …… . …… . …… . …… [3] (b) Complete the table to calculate the relative formula mass of anhydrous cobalt(II) sulfate, CoSO4. Use your Periodic Table to help you. type of atom number of atoms relative atomic mass cobalt sulfur 1 32 1 × 32 = 32 oxygen relative formula mass = …… [2] (c) Complete the table to show the number of electrons, protons and neutrons in the oxygen atom and cobalt ion shown. number of number of number of electrons neutrons protons 8O 17 27Co 59 2+ 27 [4] (d) Anhydrous cobalt(II) chloride is used to test for water. State the colour change when water is added to anhydrous cobalt(II) chloride. from …… to …… [2] (e) An alloy of cobalt, chromium and molybdenum is used to make cutlery. (i) Which one of the following diagrams best represents the structure of the alloy? Draw a circle around the correct answer. A B C D [1] (ii) Which one of these substances is also used to make cutlery? Tick one box. mercury sodium stainless steel graphite [1] [Total: 13] Question 7 starts on the next page.

Question

A student investigates the rate of reaction of magnesium ribbon with an excess of dilute hydrochloric acid. Mg + 2HCl MgCl 2 + H2 (a) Name the salt formed when magnesium reacts with dilute hydrochloric acid. . …… [1] (b) The graph shows how the volume of hydrogen produced changes with time. 60 50 40 volume of hydrogen / cm3 30 20 10 0 0 20 40 60 80 100 120 140 time / s (i) Describe how the rate of reaction changes with time. Use the graph to explain your answer. . …… . …… . …… [2] (ii) How many seconds did it take to collect the first 25 cm3 of hydrogen? …… s [1] (iii) The experiment is repeated at a higher temperature. All other conditions are kept the same. Draw a line on the grid for the experiment using a higher temperature. [2] (iv) If 2.4 g of magnesium is used, 0.2 g of hydrogen is produced. Calculate the mass of magnesium needed to produce 0.8 g of hydrogen using an excess of dilute hydrochloric acid. mass of magnesium = …… g [1] [Total: 7]

Question

(a) Oxides of nitrogen are pollutants in the air. (i) One source of oxides of nitrogen in the air is from the manufacture of nitric acid. State one other source of oxides of nitrogen in the air. . …… [1] (ii) State one adverse effect of oxides of nitrogen on health. . …… [1] (iii) Oxides of nitrogen act as catalysts. What is meant by the term catalyst ? . …… . …… [1] (iv) Oxides of nitrogen are formed during the manufacture of nitric acid. Which one of the pH values could be the pH of nitric acid? Draw a circle around the correct answer. pH 1 pH 7 pH 10 pH 14 [1] (b) Nitrogen is present in fertilisers. Why are fertilisers added to the soil where crops are grown? . …… . …… [1] (c) The table shows some observations about the reactivity of four metals with dilute hydrochloric acid. metal reaction with hydrochloric acid calcium a rapid stream of bubbles is seen lead no bubbles are seen manganese a slow stream of bubbles is seen tin a few bubbles slowly form Use the information in the table to put the four metals in order of their reactivity. Put the least reactive metal first. least reactive most reactive [2] (d) Calcium melts at 839 °C and boils at 1484 °C. What is the physical state of calcium at 1600 °C? . …… [1] [Total: 8] 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 20 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.).