Chemistry 0620/33 October/November 2019: question paper and mark scheme

Question

This question is about solids and gases. (a) The list gives the names of eight substances which are gases at room temperature. ammonia butane carbon dioxide carbon monoxide chlorine methane propene sulfur dioxide Answer the following questions about these gases. Each gas may be used once, more than once or not at all. State which gas: (i) is a poisonous product formed by the incomplete combustion of carbon . …… [1] (ii) is an alkene . …… [1] (iii) is formed when limestone is thermally decomposed . …… [1] (iv) is an element . …… [1] (v) causes acid rain. . …… [1] (b) When a piece of solid carbon dioxide is placed in a warm room, it undergoes sublimation. (i) What is meant by the term sublimation? . …… . …… [2] (ii) Use the kinetic particle model to describe the motion and separation of the particles in: solid carbon dioxide . …… . …… . …… carbon dioxide gas. …… . …… . …… [4] [Total: 11]

Question

Biogas is made by fermenting animal and vegetable waste. (a) The table shows the percentage composition of the gases present in a sample of biogas. percentage substance present present in biogas carbon dioxide 36.8 hydrogen 0.6 methane 54.5 nitrogen 6.5 water vapour other substances 0.1 total 100.0 (i) Deduce the percentage of water vapour present in this sample of biogas. . …… [1] (ii) Complete the dot-and-cross diagram to show the electron arrangement in a molecule of water. Show outer shell electrons only. O H H [2] (iii) Describe a chemical test for water. test . …… observation …… [2] (b) (i) Balance the chemical equation for the oxidation of methane to form hydrogen. ……CH4 + O2 2CO + ……H2[2] (ii) Which one of these compounds belongs to the same homologous series as methane? Draw a circle around the correct answer. butane butene methanoic acid methanol[1] (c) Methane is present in the refinery gas fraction produced by the fractional distillation of petroleum. (i) Match the fractions on the left with their uses on the right. The first one has been done for you. fraction use refinery gas making polishes gasoline fraction making roads lubricating fraction fuel for heating and cooking bitumen fuel for cars [2] (ii) Describe the fractional distillation of petroleum. In your answer: ●● state the physical property on which the separation of the fractions depends ●● describe how the distillation is done to separate the fractions. . …… . …… . …… . …… . …… . …… [3] (d) The biogas fermentation mixture contains a small amount of compound M. The structure of compound M is shown. H H O N C C H O H H C H H C H S H C H H (i) On the structure shown, draw a circle around the carboxylic acid functional group. [1] (ii) How many different types of atoms are present in compound M? . …… [1] [Total: 15]

Question

A student investigated the reaction of magnesium carbonate with an excess of dilute hydrochloric acid. MgCO3 + 2HCl MgCl 2 + CO2 + H2O The rate of reaction can be found by measuring the decrease in the mass of the reaction mixture over time. The results are shown on the graph. 180.0 A 179.8 179.6 mass of reaction B mixture / g 179.4 179.2 C D 179.0 0 20 40 60 80 100 120 140 time / s (a) Determine the mass of the reaction mixture after 58 seconds. . …… [1] (b) At which point on the graph, A, B, C or D, was the rate of reaction the fastest? Use the graph to explain your answer. . …… . …… [2] (c) When 0.42 g of magnesium carbonate is used, 120 cm3 of carbon dioxide is formed. Determine the volume of carbon dioxide produced when 1.26 g of magnesium carbonate reacts completely. volume of carbon dioxide = …… cm3 [1] (d) What effect do the following have on the rate of this reaction? ●● Decreasing the concentration of the acid. All other conditions are kept the same. . …… ●● Using smaller pieces of magnesium carbonate. All other conditions are kept the same. . …… [2] [Total: 6]

Question

This question is about sulfur and compounds of sulfur. An isotope of sulfur is written as shown. 16S 33 (a) Deduce the number of protons, electrons and neutrons in this isotope of sulfur. number of protons …… number of electrons . …… number of neutrons …… [3] (b) Draw the electronic structure of a sulfur atom. [2] (c) The table shows some observations made when four metals are heated with liquid sulfur. metal observations copper turns black very slowly gold no reaction sodium reacts explosively tin turns black slowly Use this information to put the four metals in order of their reactivity. Put the least reactive metal first. least reactive most reactive [2] (d) Name one source of sulfur. . …… [1] (e) Sulfur is used in the manufacture of sulfur dioxide and sulfuric acid. (i) Give one different use of sulfur dioxide. . …… [1] (ii) Complete the word equation for the reaction of dilute sulfuric acid with magnesium. sulfuric acid + magnesium + [2] [Total: 11]

Question

This question is about Group I elements. (a) The properties of some Group I elements are shown in the table. melting point boiling point relative thermal atomic element in °C in °C conductivity radius / pm lithium 1342 84 152 sodium 97 883 142 186 potassium 63 760 102 rubidium 39 686 58 248 (i) Complete the table to estimate: ●● the melting point of lithium ●● the atomic radius of potassium. [2] (ii) Describe the trend in the boiling points of the Group I elements down the group. . …… [1] (iii) Caesium is below rubidium in Group I. Use the information in the table to suggest why it is difficult to predict the thermal conductivity of caesium. . …… . …… [1] (iv) Predict the physical state of rubidium at 45 °C. Give a reason for your answer. . …… . …… [2] (b) Lithium reacts with oxygen to form lithium oxide. (i) Balance the chemical equation for this reaction. ……Li + O2 ……Li2O[2] (ii) Is lithium oxide an acidic oxide or a basic oxide? Give a reason for your answer. . …… . …… . …… [1] (iii) State the name of the particle which is lost from a lithium atom when it forms a lithium ion. . …… [1] (iv) A compound of lithium has the formula C2H5Li. Complete the table to calculate the relative molecular mass of C2H5Li. Use your Periodic Table to help you. number relative type of atom of atoms atomic mass carbon hydrogen 5 1 5×1=5 lithium relative molecular mass = …… [2] [Total: 12]

Question

Sodium hydroxide and ammonia are both bases. They both turn red litmus blue. (a) The chemical equation shows a reaction that produces sodium hydroxide. Na2CO3 + Ca(OH)2 2NaOH + CaCO3 Complete the word equation for this reaction. …… …… sodium …… + + hydroxide [2] (b) Aqueous sodium hydroxide can be used to test for chromium(III) ions and iron(II) ions. Complete the table to show the expected observations. observation on adding a small observation on adding an excess ion volume of aqueous sodium hydroxide of aqueous sodium hydroxide chromium(III) (Cr3+) iron(II) (Fe2+) [3] (c) A student set up a long glass tube as shown. cotton wool soaked damp red litmus paper in aqueous ammonia At first, the litmus paper remained red. After a short time the litmus paper was completely blue. Explain these observations using the kinetic particle model. . …… . …… . …… . …… . …… . …… [3] (d) Oxides of nitrogen are formed when ammonia is heated with oxygen in the presence of a catalyst. (i) Suggest why a catalyst is used. . …… [1] (ii) State one other process which puts oxides of nitrogen into the atmosphere. . …… [1] (iii) State one adverse effect of oxides of nitrogen on health. . …… [1] (e) Ammonium nitrate is present in many fertilisers. Which one of these compounds is also present in many fertilisers? Tick one box. barium hydroxide potassium phosphate sodium chloride tin(II) sulfate [1] (f) When ammonium chloride dissolves in water, the temperature of the solution decreases. What is the name for a reaction where the temperature of the solution decreases? . …… [1] [Total: 13]

Question

Aluminium is manufactured by the electrolysis of molten aluminium oxide. (a) Predict the products of the electrolysis of molten aluminium oxide at: the positive electrode . …… the negative electrode. …… [2] (b) Complete these sentences about the uses of aluminium using words from the list. conductivity corrosion density heavy malleability reduction strong weak Aluminium is used in the manufacture of aircraft because it is relatively …… and has a low …… . Aluminium is used for food containers because of its resistance to …… . [3] (c) The following statements are about the procedure for making crystals of hydrated aluminium sulfate from aluminium hydroxide and sulfuric acid. A Filter off the excess aluminium hydroxide. B Filter off the crystals and dry between filter papers. C Warm the filtrate to the point of crystallisation. D Add aluminium hydroxide to warm dilute sulfuric acid and stir. E Leave the mixture at room temperature to form more crystals. F Add more aluminium hydroxide to the sulfuric acid until the aluminium hydroxide is in excess. Put the statements A, B, C, D, E and F in the correct order. The first one has been done for you. D [2] [Total: 7]

Question

This question is about dyes. (a) Chromatography can be used to separate a mixture of dyes. S, T, U and W are four different mixtures of dyes. S, T, U and W were placed on a piece of chromatography paper. Two pure dyes, X and Y, were also placed on the same piece of chromatography paper. The results of the chromatography are shown. S T U W X Y (i) Which mixture, S, T, U or W, contains dye X but not dye Y? . …… [1] (ii) Which mixture, S, T, U or W, contains the smallest number of dyes? . …… [1] (iii) Which mixture, S, T, U or W, contains neither dye X nor dye Y? . …… [1] (b) Indigo is a blue dye. When an alkaline solution of indigo undergoes reduction, it turns colourless. (i) What is meant by the term reduction? . …… [1] (ii) A piece of white cloth is soaked in the colourless solution. When the cloth is left in the air it turns blue. What type of chemical reaction occurs? Draw a circle around the correct answer. decomposition fermentation oxidation polymerisation[1] [Total: 5] 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.).