Chemistry 0620/32 February/March 2023: question paper and mark scheme

Question

A list of symbols and formulae is shown. Br2 CH4 C 2H 4 Cl – CO2 Cr3+ Cu2+ H2 K+ N2 N3– O2 SO42– Answer the following questions about these symbols and formulae. Each symbol or formula may be used once, more than once or not at all. State which symbol or formula represents: (a) a molecule containing only five atoms . …… [1] (b) a diatomic molecule of an element in Group VII of the Periodic Table . …… [1] (c) an ion formed when an atom gains one electron . …… [1] (d) an ion which forms a green precipitate when a few drops of aqueous sodium hydroxide are added to it . …… [1] (e) a compound produced by the thermal decomposition of calcium carbonate . …… [1] (f) a product of photosynthesis. . …… [1] [Total: 6]

Question

(a) A sample of soil is shaken with distilled water. Draw a diagram to show the filtration apparatus used to separate the soil from the solution obtained by shaking the soil with distilled water. On your diagram, label: ● the filtrate ● the residue. [3] (b) Table 2.1 shows the masses of some of the ions in 1000 cm3 of the solution obtained by filtering a sample of soil with distilled water. Table 2.1 mass of ion in 1000 cm3 name of ion formula of ion of solution / mg ammonium NH4+ 25.0 calcium Ca2+ 0.4 chloride Cl – 0.5 iron(II) Fe2+ 27.0 magnesium Mg2+ 4.0 nitrate NO3– 23.0 phosphate PO43– 15.5 potassium K+ 29.0 sodium Na+ 2.0 SO42– 6.0 Answer these questions using the information in Table 2.1. (i) Name the negative ion that has the lowest concentration. . …… [1] (ii) State the name of the SO42– ion. . …… [1] (iii) Calculate the mass of phosphate ions in 200 cm3 of the solution. mass = …… mg [1] (c) Complete Fig. 2.1 to show: ● the electronic configuration of a sodium ion ● the charge on the ion. Na Fig. 2.1 [2] (d) Water from natural sources contains dissolved gases. Choose from the list the gas which is essential for aquatic life. Draw a circle around your chosen answer. argon hydrogen nitrogen oxygen[1] (e) Polluted water may contain sewage or nitrates. State one harmful effect of each of these water pollutants. sewage …… nitrates . …… [2] [Total: 11]

Question

This question is about compounds of nitrogen. (a) Complete the dot-and-cross diagram in Fig. 3.1 of a molecule of ammonia. Show outer shell electrons only. H N H H Fig. 3.1 [2] (b) Oxides of nitrogen are air pollutants. (i) State one source of oxides of nitrogen in the air. . …… [1] (ii) State one adverse effect of oxides of nitrogen. . …… [1] (c) State whether nitrogen dioxide is an acidic or basic oxide. Give a reason for your answer. . …… . …… [1] [Total: 5]

Question

This question is about metals and compounds of metals. (a) Table 4.1 shows some properties of five metals, A, B, C, D and E. Table 4.1 density melting point colour of metal in g / cm3 in °C metal chloride A 5.90 30 white B 5.96 1890 green C 11.34 328 white D 8.90 1455 yellow E 1.53 39 white State which two of these metals, A, B, C, D and E, are transition elements. Give two reasons for your answer using only the information in Table 4.1. metals …… and …… reason 1 . …… reason 2 . …… [3] (b) Choose the metal chloride that is insoluble in water. Tick (✓) one box. magnesium chloride potassium chloride silver chloride sodium chloride [1] (c) Magnesium chloride is produced when magnesium burns in chlorine. Mg + Cl 2 → MgCl 2 Fig. 4.1 shows an incomplete reaction pathway diagram for this reaction. energy progress of reaction Fig. 4.1 (i) Complete Fig. 4.1 by writing these formulae on the diagram: ● Mg + Cl 2 ● MgCl 2. [1] (ii) Explain how Fig. 4.1 shows that the reaction is exothermic. . …… . …… [1] (d) Table 4.2 shows the reactions of four different metals with steam. Table 4.2 metal reaction with steam iron reacts slowly magnesium reacts very rapidly nickel reacts very slowly niobium does not react Put the four metals in order of their reactivity. Put the least reactive metal first. least reactive most reactive [2] (e) A compound of nickel has the molecular formula NiP4F12. Complete Table 4.3 to calculate the relative molecular mass of NiP4F12. Table 4.3 relative atom number of atoms atomic mass fluorine 12 19 12 × 19 = 228 nickel 59 phosphorus 31 relative molecular mass = …… [2] [Total: 10]

Question

Potassium iodide is an ionic compound. (a) State two properties of an ionic compound. 1 . …… 2 . …… [2] (b) Molten potassium iodide is electrolysed using graphite electrodes. (i) Name the products formed at the positive and negative electrodes. positive electrode . …… negative electrode …… [2] (ii) State the name of the positive electrode in an electrolysis experiment. . …… [1] (c) Deduce the number of protons and neutrons in the iodide ion shown. 53I 127 – number of protons …… number of neutrons …… [2] (d) Aqueous chlorine reacts with aqueous potassium iodide. (i) Complete the symbol equation for this reaction. Cl 2 + 2KI → …… + ....KCl[2] (ii) Choose from the list the name of this type of reaction. Draw a circle around your chosen answer. addition combustion displacement neutralisation[1] (iii) State the colour of chlorine gas at room temperature and pressure. . …… [1] [Total: 11]

Question

(a) Fig. 6.1 shows the displayed formula of a molecule of crotyl alcohol. H H H H C C C C O H H H H Fig. 6.1 (i) On Fig. 6.1 draw a circle around the alcohol functional group. [1] (ii) Describe the feature of crotyl alcohol that shows it is an unsaturated compound. . …… [1] (iii) Deduce the molecular formula of crotyl alcohol. . …… [1] (iv) Crotyl alcohol is soluble in water. The boiling point of crotyl alcohol is 121 °C. The boiling point of water is 100 °C. Suggest how fractional distillation can be used to separate a mixture of crotyl alcohol and water. . …… . …… . …… [2] (b) Ethanol is also an alcohol. Describe two conditions for the manufacture of ethanol by the fermentation of aqueous glucose. 1 . …… 2 . …… [2] (c) Ethanol can be converted to ethene. Choose from the list the general formula for the homologous series to which ethene belongs. Draw a circle around your chosen answer. CnHn CnH2n CnH2n+2 C2nHn[1] (d) Ethene can be converted to ethane. (i) Ethane is an alkane. Name the type of bonding in alkanes. . …… [1] (ii) Draw the displayed formula of a molecule of ethane. [1] (iii) Complete this sentence. Alkanes are unreactive except in terms of combustion and substitution by …… . [1] (iv) Complete the symbol equation for the complete combustion of methane. CH4 + ……O2 → …… + 2H2O[2] [Total: 13]

Question

This question is about iron. (a) Iron is extracted from iron ore in a blast furnace. (i) Name the main ore of iron. . …… [1] (ii) The main ore of iron contains iron(III) oxide. Describe the extraction of iron from iron ore in the blast furnace. In your answer, describe: ● the production of carbon monoxide . …… . …… . …… ● the role of carbon monoxide . …… ● the role of calcium carbonate, added to the blast furnace. . …… . …… . …… [4] (iii) Iron collects at the base of the blast furnace as a liquid. Describe the arrangement and motion of the particles in a liquid. arrangement …… . …… motion . …… . …… [2] (b) The equation for the reaction of iron with steam is shown. 3Fe + 4H2O → Fe3O4 + 4H2 Describe how this equation shows that iron is oxidised. . …… [1] (c) Rust is hydrated iron(III) oxide. (i) Define the term hydrated. . …… . …… [1] (ii) Name the two substances needed for iron to rust. …… and . …… [2] (d) Crystals of iron(II) chloride can be prepared by adding excess iron to dilute hydrochloric acid. (i) Suggest how the unreacted iron is removed from the reaction mixture. . …… [1] Describe how dry crystals of iron(II) chloride are made from a dilute solution of (ii) iron(II) chloride. . …… . …… . …… [2] [Total: 14]

Question

A student investigates the reaction of iron powder with dilute hydrochloric acid at 20 °C. The hydrochloric acid is in excess. (a) Fig. 8.1 shows the volume of hydrogen gas released as the reaction proceeds. 60 50 40 volume of hydrogen gas / cm3 30 20 10 0 0 1 2 3 4 5 6 7 time / min Fig. 8.1 (i) Deduce the volume of hydrogen gas released after 2 minutes. volume of hydrogen gas = …… cm3 [1] (ii) The student repeats the experiment using dilute hydrochloric acid of a higher concentration. All other conditions stay the same. Draw a line on the grid in Fig. 8.1 to predict how the volume of hydrogen gas changes when dilute hydrochloric acid of a higher concentration is used. [2] (b) (i) The student repeats the experiment with large pieces of iron. All other conditions stay the same. Describe how the rate of reaction differs when large pieces of iron are used. . …… [1] (ii) The student repeats the experiment with iron powder at a temperature of 15 °C. All other conditions stay the same. Describe how the rate of reaction differs when a temperature of 15 °C is used. . …… [1] (c) Hydrochloric acid also reacts with aqueous sodium hydroxide. (i) Complete the word equation for this reaction. hydrochloric sodium …… + + acid hydroxide …… [2] (ii) Write the formula of the ion present in all acids. . …… [1] (iii) Choose from the list a possible pH value of aqueous sodium hydroxide. Draw a circle around your chosen answer. pH 2 pH 4 pH 7 pH 13[1] (iv) State the colour of methyl orange in aqueous sodium hydroxide. . …… [1] [Total: 10] 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 16 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.).