Chemistry 0620/31 May/June 2024: question paper and mark scheme

Question

Fig. 1.1 shows the structures of seven substances, A, B, C, D, E, F and G. A B C D H Na+ Br – Na+ Br – O C H H Br – Na+ Br – Na+ H H H Na+ Br – Na+ Br – E F G Zn Zn Zn Zn H Cu Zn Cu Cu Zn Zn Zn Zn H C O H Cu Cu Cu Zn Zn Zn Zn Zn Cu Zn Cu Cu H Fig. 1.1 (a) Answer the following questions using only the structures in Fig. 1.1. Each structure may be used once, more than once or not at all. State which structure represents: (i) an alloy . …… [1] (ii) a substance that only conducts electricity when molten or in aqueous solution . …… [1] (iii) a giant covalent structure . …… [1] (iv) a compound that is a product formed in a hydrogen–oxygen fuel cell . …… [1] (v) a compound with a high melting point . …… [1] (vi) a gas that is responsible for increased global warming. . …… [1] (b) Complete Fig. 1.2 to show the dot-and-cross diagram for structure C. Show the outer shell electrons only. O H H Fig. 1.2 [2] [Total: 8]

Question

(a) Table 2.1 shows the percentages by mass of the elements present in the human body. Table 2.1 percentage by element mass of element calcium 1.50 carbon 18.00 chlorine 0.15 hydrogen 10.00 magnesium 0.05 nitrogen 3.00 oxygen 65.00 phosphorus 1.00 potassium 0.35 sodium 0.15 sulfur 0.25 other elements 0.55 Answer these questions using information from Table 2.1. (i) Name the non-metallic element in Table 2.1 that has the lowest percentage by mass. . …… [1] (ii) Name an element in Table 2.1 that is in Period 4 of the Periodic Table. . …… [1] (b) Some medicines contain a compound made of Mg2+ ions and OH– ions. Name the compound made of Mg2+ ions and OH– ions. . …… [1] (c) Describe the observations when aqueous sodium hydroxide is added dropwise to a solution containing calcium ions until the sodium hydroxide is in excess. observations with dropwise addition of sodium hydroxide . …… observations with excess sodium hydroxide . …… [2] (d) Name a calcium salt that is soluble in water. . …… [1] (e) Table 2.2 shows some properties of the Group I metals. Table 2.2 melting point observations on metal / °C reaction with water lithium 181 bubbles form rapidly sodium 98 but no flame bubbles form very rapidly potassium and flame rubidium 39 explodes Use the information in Table 2.2 to predict: ● the melting point of potassium . …… ● the observations when lithium reacts with water. . …… [2] (f) State how the density of the Group I elements changes down the group. . …… [1] (g) Sodium reacts with water to produce sodium hydroxide and a gas which pops with a lighted splint. Complete the symbol equation for this reaction. ……Na + 2H2O → 2NaOH + …… [2] [Total: 11]

Question

Aluminium is extracted by electrolysis of its purified ore. (a) Name the main ore of aluminium. . …… [1] (b) Fig. 3.1 shows the apparatus used in the extraction of aluminium. + power – supply steel case Fig. 3.1 (i) Label the cathode in Fig. 3.1. [1] (ii) The electrolyte contains molten aluminium oxide. State the product formed at each electrode. positive electrode . …… negative electrode …… [2] (c) State two physical properties that explain why aluminium is used in overhead electrical cables. 1 . …… 2 . …… [2] (d) Aluminium ore is purified by reacting it with sodium hydroxide. Sodium hydroxide is an alkali. (i) State the meaning of the term alkali. . …… [1] (ii) Describe how to find the pH of a dilute solution of sodium hydroxide using universal indicator paper. . …… . …… [2] (iii) A dilute solution of sodium hydroxide is added to a solution of methyl orange in acid until the sodium hydroxide is in excess. State the colour change of the methyl orange. [Total: 11]

Question

(a) Fig. 4.1 shows the displayed formula of a compound extracted from a plant. H H H C H H H C H H C C C C C H H C H C H H C H H H H O H Fig. 4.1 On Fig. 4.1, draw a circle around one functional group that makes this compound unsaturated. [1] (b) A student extracts mixtures of coloured compounds from four different plants, Q, R, S and T. Fig. 4.2 shows the results of chromatography of these mixtures using an organic solvent. solvent front filter paper Q R S T Fig. 4.2 (i) Deduce which plant, Q, R, S or T, contains the greatest number of coloured compounds. . …… [1] (ii) Deduce which two plants, Q, R, S or T, contain exactly the same coloured compounds. (iii) State the meaning of the term solvent. . …… [1] (c) (i) Plants produce glucose and oxygen by photosynthesis. Complete the word equation for photosynthesis. + → glucose + oxygen [2] (ii) Name one other substance that is essential for photosynthesis. . …… [1] [Total: 7]

Question

(a) An atom of carbon is represented by the symbol shown. 6C 14 Describe this atom of carbon in terms of: ● the position of the electrons, neutrons and protons in this atom . …… . …… . …… ● the number of neutrons and number of protons . …… . …… ● the electronic configuration. . …… [5] (b) (i) Complete the symbol equation for the incomplete combustion of carbon to produce carbon monoxide. ……C + O2 → ……CO [2] (ii) State one adverse effect of carbon monoxide. . …… [1] (c) Fig. 5.1 shows the displayed formula of chromium carbonyl. O O C O C C Cr C C O C O O Fig. 5.1 Deduce the molecular formula of chromium carbonyl. . …… [1] (d) Another compound of chromium has the formula Na2Cr2C10O10. Complete Table 5.1 to calculate the relative molecular mass of Na2Cr2C10O10. Table 5.1 relative type of atom number of atoms atomic mass sodium 2 23 2 × 23 = 46 chromium 52 carbon 12 oxygen 16 relative molecular mass = …… [2] (e) Chromium can be produced by heating chromium(III) oxide, Cr2O3, with carbon. Cr2O3 + 3C → 2Cr + 3CO Describe how this equation shows that chromium(III) oxide is reduced. . …… . …… [1] [Total: 12]

Question

Large pieces of solid sulfur burn in excess oxygen to produce sulfur dioxide gas. (a) Complete the equation by adding the missing state symbol. S(……) + O2(g) → SO2(g)[1] (b) Fig. 6.1 shows how the mass of sulfur changes as the reaction proceeds. 40 30 mass of 20 sulfur / g 10 0 0 20 40 60 80 100 120 140 time / seconds Fig. 6.1 Deduce the time taken for the reaction to finish. . …… [1] (c) The experiment is repeated using powdered sulfur. Describe the effect on the rate of reaction of using powdered sulfur rather than large pieces of sulfur. . …… [1] (d) Sulfur dioxide reacts with oxygen in a closed container. 2SO2(g) + O2(g) 2SO3(g) (i) Describe the effect, if any, each of the following has on the rate of this reaction. All other conditions stay the same. ● The temperature is decreased. . …… ● The pressure of the gases is increased. . …… [2] (ii) Changing concentration changes the rate of a reaction. Choose the correct unit of concentration from the list. Draw a circle around your chosen answer. dm3 / mol mol / dm mol / dm2 mol / dm3[1] (e) Sulfur dioxide is an air pollutant. (i) State one adverse effect of sulfur dioxide. . …… [1] (ii) Emissions of sulfur dioxide can be reduced by using low-sulfur fossil fuels. State one other way of reducing sulfur dioxide emissions from fossil fuels. . …… [1] (f) Aqueous sodium hydrogen sulfite releases sulfur dioxide gas at room temperature. Sulfur dioxide changes the colour of acidified potassium manganate(VII) from purple to colourless. Fig. 6.2 shows a sealed tube with a small volume of aqueous sodium hydrogen sulfite at the bottom. A piece of filter paper soaked in acidified potassium manganate(VII) is attached to the top of the tube. filter paper soaked in acidified potassium manganate(VII) aqueous sodium hydrogen sulfite Fig. 6.2 The filter paper remains purple at first. The filter paper becomes colourless after a short time. Explain these results in terms of kinetic particle theory. . …… . …… . …… . …… [3] [Total: 11]

Question

Iron is a metal. Iron has a high density, a high melting point and a high boiling point. (a) State three other physical properties of iron. 1 . …… 2 . …… 3 . …… [3] (b) (i) State the conditions needed for iron to rust. . …… . …… [2] (ii) Rust is hydrated iron(III) oxide. State if iron(III) oxide is an acidic or basic oxide. Give a reason for your answer. . …… . …… [1] (iii) Complete this sentence about methods of preventing rusting. Rusting can be prevented by painting or …… . …… [1] (c) The list shows five metals. calcium copper iron silver sodium Put these metals in order of their reactivity. Put the most reactive metal at the top. most reactive least reactive [2] (d) Complete the word equation for the reaction of calcium carbonate with nitric acid. calcium nitric …… …… + → + water + carbonate acid [2] [Total: 11]

Question

(a) Fig. 8.1 shows the displayed formulae of five organic compounds, V, W, X, Y and Z. V W X H H H H H O H C C C H H C C O H H C H H H H H O H Y Z H O H H H H C C H C C C H O H H H Fig. 8.1 (i) State which two of the compounds, V, W, X, Y and Z, are in the same homologous series. (ii) Explain why compound V is an alkane. . …… . …… [2] (iii) State the name of the homologous series to which compound X belongs. . …… [1] (b) Ethanol can be manufactured by the catalytic addition of steam to ethene. (i) State the temperature and pressure required for this reaction. temperature …… °C pressure . …… atm [2] (ii) Name one other method of manufacturing ethanol. . …… [1] (c) Describe how alkenes are manufactured from petroleum fractions. . …… . …… . …… [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 89–103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 actinoids Fr Ra Rf Db Sg Bh Hs Mt Ds Rg Cn Nh Fl Mc Lv Ts Og francium radium rutherfordium dubnium seaborgium bohrium hassium meitnerium darmstadtium roentgenium copernicium nihonium flerovium moscovium livermorium tennessine oganesson – – – – – – – – – – – – – – – – – 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.).