Chemistry 0620/31 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. He Li+ Cl – Li+ Cl – He He Cl – Li+ Cl – Li+ He He Li+ Cl – Li+ Cl – He Cl – Li+ Cl – Li+ A B C N N Cu Cu Cu Cu N N Cu Cu Cu Cu N Cu Cu Cu Cu N N N N N Cu Cu Cu Cu D E (a) Answer the following questions about these structures. Each structure may be used once, more than once or not at all. (i) Which two of these structures, A, B, C, D or E, are covalently bonded? …… and . …… [2] (ii) Which one of these structures, A, B, C, D or E, is a diatomic molecule? . …… [1] (iii) Which one of these structures, A, B, C, D or E, is a compound? . …… [1] (iv) Which one of these structures, A, B, C, D or E, is very soluble in water? . …… [1] (v) Which one of these structures, A, B, C, D or E, is used in cutting tools? . …… [1] (vi) Which one of these structures, A, B, C, D or E, is used in electrical wiring? . …… [1] (b) Substance B is an element. What is meant by the term element ? . …… . …… [1] [Total: 8]

Question

This question is about iron and iron compounds. (a) Name the main ore of iron. . …… [1] (b) In a blast furnace used for the extraction of iron, carbon reacts with oxygen from the air to form carbon monoxide. Complete the chemical equation for this reaction. ....C + …… 2CO [2] (c) In the hotter parts of the furnace, carbon reacts with the iron(III) oxide present in the iron ore. 3C + Fe2O3 3CO + 2Fe How does this equation show that carbon is oxidised? . …… . …… [1] (d) Limestone is added to the blast furnace. The limestone is converted into calcium oxide and carbon dioxide. The reaction is endothermic. heat CaCO3 CaO + CO2 (i) What type of chemical reaction is this? . …… [1] (ii) What type of oxide is calcium oxide? Give a reason for your answer. . …… . …… [2] (e) Iron is a metal. Give three physical properties that are characteristic of metals. 1 . …… 2 . …… 3 . …… [3] (f) The structure of a compound of iron is shown. O OC C CO OC Fe Fe CO C OC O CO C O Deduce the molecular formula of this compound to show the number of iron, carbon and oxygen atoms. . …… [1] [Total: 11]

Question

(a) The table shows the percentage by mass of the elements on Earth and in the Universe. percentage by percentage by mass element mass on Earth in the Universe helium 0.0 21.0 hydrogen 0.1 76.0 iron 35.0 1.0 magnesium 14.0 0.1 oxygen 29.0 0.8 silicon 14.0 0.1 sulfur 2.9 0.1 other elements 0.9 total 100.0 100.0 Answer these questions using only the information in the table. (i) Deduce the percentage by mass of other elements present on Earth. …… % [1] (ii) Which non-metallic element is present on Earth in the greatest percentage by mass? . …… [1] (iii) Give two major differences in the percentage by mass of the elements on Earth and in the Universe. 1 . …… . …… 2 . …… . …… [2] (b) Complete the diagram to show the electron arrangement in an oxygen atom. [1] (c) Helium, neon and argon are noble gases. (i) Explain, in terms of the electronic structure, why neon is unreactive. . …… . …… [1] (ii) State one use of argon. . …… [1] [Total: 7]

Question

This question is about iodine and compounds of iodine. (a) Use the kinetic particle model to describe the separation between the molecules and the type of motion of the molecules in: ●● solid iodine . …… . …… ●● iodine gas. …… . …… [4] (b) The graph shows how the volume of iodine gas changes with pressure. The temperature is kept constant. volume of iodine gas 0 0 pressure Describe how the volume of iodine gas changes with pressure. . …… . …… [1] (c) (i) Complete the word equation to show the halogen and halide compound which react to form the products iodine and potassium bromide. …… …… potassium + iodine + bromide [2] (ii) Explain, in terms of the reactivity of the halogens, why aqueous iodine does not react with aqueous potassium chloride. . …… . …… [1] (d) Iodine reacts with aqueous sodium thiosulfate, Na2S2O3. (i) Balance the chemical equation for this reaction. ……Na2S2O3 + I2 Na2S4O6 + ……NaI [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 iodide ions. test . …… observations …… [2] (f) Molten sodium iodide is electrolysed. Predict the product at the positive electrode. . …… [1] [Total: 14]

Question

Coal gas is made by heating coal in the absence of air. The list shows the main gases present in coal gas. carbon dioxide carbon monoxide ethene hydrogen methane nitrogen (a) (i) Which one of these gases is an alkane? . …… [1] (ii) Draw the structure of a molecule of ethene. Show all of the atoms and all of the bonds. [1] (iii) Describe how aqueous bromine can be used to tell the difference between methane and ethene. . …… . …… . …… [2] (b) Ethene molecules react with each other to form poly(ethene). (i) What is the name given to this type of chemical reaction? . …… [1] (ii) Which one of the following words describes the ethene molecules in this reaction? Draw a circle around the correct answer. elements mixtures monomers polymers [1] (iii) Poly(ethene) is a non-biodegradable plastic. What is meant by the term non-biodegradable? . …… . …… [1] (iv) Describe one pollution problem caused by non-biodegradable plastics. . …… . …… [1] (c) Ethanol can be made from ethene and one other reactant. ●● Name the other reactant. . …… ●● State the conditions needed to make ethanol from ethene. . …… . …… [3] [Total: 11]

Question

This question is about copper and copper compounds. (a) Describe how you could prepare a pure sample of crystals of hydrated copper(II) sulfate using dilute sulfuric acid and an excess of copper(II) oxide. . …… . …… . …… . …… . …… [3] (b) Anhydrous copper(II) sulfate is used to test for water. CuSO4 + 5H2O CuSO4.5H2O anhydrous hydrated copper(II) sulfate copper(II) sulfate (i) What is meant by the symbol ? . …… [1] (ii) How can hydrated copper(II) sulfate be changed into anhydrous copper(II) sulfate? . …… [1] (c) Complete the table to calculate the relative formula mass of anhydrous copper(II) sulfate, CuSO4. Use your Periodic Table to help you. number relative type of atom of atoms atomic mass copper 1 64 1 × 64 = 64 sulfur oxygen relative formula mass = …… [2] (d) Complete the table to show the number of electrons, protons and neutrons in the sulfur atom and copper ion shown. number of number of number of electrons neutrons protons 16S 34 29Cu 63 2+ 29 [4] (e) Alloys of copper are used to make coins. (i) What is meant by the term alloy? . …… . …… [1] (ii) Suggest why an alloy of copper is used to make coins instead of using pure copper. . …… [1] [Total: 13]

Question

A student investigates the rate of reaction of small pieces of calcium carbonate with an excess of hydrochloric acid of concentration 1 mol / dm3. CaCO3(s) + 2HCl (aq) CaCl 2(aq) + CO2(g) + H2O(l) (a) Name the salt formed when calcium carbonate reacts with hydrochloric acid. . …… [1] (b) The graph shows how the mass of the reaction mixture changes with time. 200.0 199.8 199.6 mass of reaction mixture /g 199.4 199.2 199.0 198.8 0 20 40 60 80 100 120 140 time / s (i) State why the reaction mixture decreases in mass. . …… [1] (ii) Calculate the loss in mass during the first 40 seconds of the experiment. …… g [1] (iii) The experiment is repeated using hydrochloric acid of concentration 2 mol / dm3. All other conditions are kept the same. Draw a line on the grid for the experiment using hydrochloric acid of concentration 2 mol / dm3.[2] (iv) In the experiment, when 2.00 g of calcium carbonate is used, the loss in mass of the reaction mixture is 0.88 g. All other conditions are kept the same. Calculate the loss in mass when 0.50 g of calcium carbonate is used. loss in mass = …… g [1] (v) The experiment is repeated using the same mass of different sized pieces of calcium carbonate. All other conditions are kept the same. The sizes of the pieces of calcium carbonate are: ● powder ● small pieces ● large pieces. Complete the table by writing the sizes of the pieces of calcium carbonate in the first column. size of pieces of initial rate of loss calcium carbonate in mass in g / s 0.005 0.030 0.100 [1] [Total: 7]

Question

(a) Sulfur dioxide is a pollutant in the air. (i) State one source of sulfur dioxide in the air. . …… [1] (ii) Sulfur dioxide is oxidised to sulfur trioxide in the air. Oxides of nitrogen act as catalysts for this reaction. What is meant by the term catalyst ? . …… . …… [1] (iii) Sulfur trioxide dissolves in rainwater to form acid rain. Which one of the following pH values could be the pH of acid rain? Draw a circle around the correct answer. pH 4 pH 7 pH 9 pH 13 [1] (iv) State one adverse effect of acid rain on buildings. . …… [1] (b) Sulfur dioxide melts at –73 °C and boils at –10 °C. What is the physical state of sulfur dioxide at –20 °C? Explain your answer. . …… . …… [2] (c) Excess sulfuric acid reacts with ammonia to make a salt which can be used as a fertiliser. State the name of the salt formed when excess sulfuric acid reacts with ammonia. . …… [1] (d) The table shows some observations about the reactivity of four metals with dilute sulfuric acid. metal reaction with sulfuric acid iron a slow stream of bubbles is seen magnesium a rapid stream of bubbles is seen nickel a few bubbles slowly form tungsten no bubbles are seen 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] [Total: 9] 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.).