Chemistry 0620/33 October/November 2021: question paper and mark scheme

Question

(a) A list of formulae is shown. Br2 CO CO2 CH4 C 2H 6 HCl KBr LiCl MgCl 2 O2 SO2 Answer the following questions using these formulae. Each formula may be used once, more than once or not at all. State which formula represents: (i) a compound that gives a red colour in a flame test . …… [1] (ii) a compound containing an ion with a 2+ charge . …… [1] (iii) a compound that is a product of respiration . …… [1] (iv) a compound used as a food preservative . …… [1] (v) an element that is used in the production of steel. . …… [1] (b) Complete the dot-and-cross diagram to show the electron arrangement in a molecule of hydrogen chloride. Show outer shell electrons only. H Cl [2] (c) State whether carbon dioxide is a basic oxide or an acidic oxide. Give a reason for your answer. . …… . …… [1] [Total: 8]

Question

The table shows the masses of some of the ions in 1000 cm3 of water from a river. mass of ion in 1000 cm3 name of ion formula of ion of river water / mg ammonium NH4+ 1.0 Ca2+ 16.5 chloride Cl – 7.0 iron(III) Fe3+ 0.5 magnesium Mg2+ 4.0 NO3– 0.5 potassium K+ 3.5 silicate SiO32– 7.5 sodium Na+ 6.0 sulfate SO42– 11.0 (a) Answer these questions using only the information in the table. (i) State which positive ion has the lowest concentration. . …… [1] (ii) Name the compound containing Ca2+ and NO3– ions. . …… [1] (iii) Calculate the mass of sulfate ions in 500 cm3 of river water. mass = …… mg [1] (b) Describe a test for iron(III) ions. test . …… observations …… [2] (c) Compound A is found in river water. The structure of compound A is shown. H H O N C C H H C H O H O H (i) On the structure draw a circle around the alcohol functional group. [1] (ii) Deduce the formula of compound A to show the number of carbon, hydrogen, oxygen and nitrogen atoms. . …… [1] (iii) Another compound found in river water has the formula C4H8O2. Complete the table to calculate the relative molecular mass of this compound. number relative type of atom of atoms atomic mass carbon 4 12 4 × 12 = 48 hydrogen 1 oxygen 16 relative molecular mass = …… [2] [Total: 9]

Question

Iron is extracted in a blast furnace using a mixture of iron ore, coke (carbon), air and calcium carbonate (limestone). (a) Give two reasons why air is blown into the blast furnace. 1 . …… 2 . …… [2] (b) Magnetite is an ore of iron which contains a compound of iron with the formula Fe3O4. (i) Give the name of another ore of iron. . …… [1] (ii) In the blast furnace Fe3O4 is reduced to Fe. Complete the chemical equation for the reduction of Fe3O4. Fe3O4 + 4CO → ……Fe + ……CO2[2] (iii) Explain how this equation shows that Fe3O4 is reduced. . …… [1] (c) Calcium carbonate (limestone) is added to the blast furnace. The calcium carbonate undergoes thermal decomposition. Give the meaning of the term thermal decomposition. . …… [2] (d) Iron can form alloys such as vanadium steel. (i) State the meaning of the term alloy. . …… . …… [1] (ii) Choose from the diagrams, B, C, D or E, the structure which best represents an alloy. B C D E structure …… [1] (iii) The symbol for an isotope of vanadium is shown. 23V 51 Deduce the number of electrons, neutrons and protons in one atom of this isotope of vanadium. number of electrons . …… number of neutrons …… number of protons …… [3] (iv) Vanadium is malleable and conducts electricity. Give two other physical properties of vanadium that are characteristic of all metals. 1 . …… 2 . …… [2] [Total: 15]

Question

The table shows some properties of four halogens in Group VII. melting point boiling point density of liquid at halogen / °C / °C boiling point in g / cm3 chlorine –101 –35 1.56 bromine –7 59 iodine 114 4.93 astatine 302 337 6.35 (a) (i) Complete the table by predicting: ● the boiling point of iodine ● the density of bromine. [2] (ii) Describe the trend in the melting points of the halogens down Group VII. . …… [1] (b) (i) Deduce the electronic structure of chlorine. Use the Periodic Table to help you. . …… [1] (ii) Explain why a bromide ion has a single negative charge. . …… . …… [1] (c) Scientists have predicted that sodium astatide reacts with chlorine. Complete the word equation for this reaction. sodium …… …… + chlorine → + astatide [2] (d) Hydrogen chloride is produced when chlorine reacts with ammonia. An aqueous solution of hydrogen chloride is acidic. Describe how you could determine the pH of an acidic solution without using a pH meter. . …… . …… . …… [2] [Total: 9]

Question

The table shows the structures of some organic compounds. compound structure of compound homologous series H H O F H C C C O H carboxylic acid H H H H G C C H H H H H H H C C C H H H H (a) Complete the table by naming the homologous series. The first one has been done for you. [2] (b) Draw the structure of a compound containing two carbon atoms which belongs to the same homologous series as compound F. Show all of the atoms and all of the bonds. [1] (c) Compound G reacts with bromine. Choose from the structures, P, Q, R or S, the structure of the product formed. P Q R S H Br Br Br H Br Br Br H C C Br C C C C H C C H H H H H H Br H H . …… [1] (d) (i) Compound G can be obtained by cracking petroleum fractions. Describe what is meant by the term cracking. . …… . …… [2] (ii) Name the product of the reaction when compound G reacts with steam. . …… [1] (iii) Many molecules of compound G can join together to form a compound with a very long chain. Choose from the list the general name given to a compound that is formed by the addition of many small units. Draw a circle around the correct answer. isomer monomer naphtha polymer[1] (e) State the names of the two compounds formed during the complete combustion of compound H. [Total: 10]

Question

The diagram shows part of the structures of sodium chloride and pentane at room temperature and pressure. Na+ Cl – Na+ Cl – represents pentane, Cl – Na+ Cl – Na+ CH3CH2CH2CH2CH3 Na+ Cl – Na+ Cl – (a) Describe the differences in the physical properties of these substances in terms of: ● volatility sodium chloride …… pentane . …… ● solubility in water sodium chloride …… pentane . …… ● electrical conductivity when molten (liquid). sodium chloride …… pentane . …… [5] (b) Concentrated aqueous sodium chloride is electrolysed using carbon (graphite) electrodes. Name the gas produced at the positive electrode. . …… [1] (c) Pentane is a fuel. Under some conditions pentane forms carbon monoxide. (i) State the condition under which pentane forms carbon monoxide. . …… [1] (ii) State one adverse effect of carbon monoxide on health. . …… [1] [Total: 8]

Question

This question is about aluminium and the extraction of metals. (a) When aluminium is heated above 660 °C it changes from solid to liquid. (i) Name the change of state from solid to liquid. . …… [1] (ii) Use the kinetic particle theory to describe the differences between solid aluminium and liquid aluminium in terms of: ● the separation of the particles . …… . …… . …… ● the motion of the particles. . …… . …… . …… [4] (b) Aluminium is extracted from aluminium ore by electrolysis. Explain why aluminium is extracted by electrolysis and not by reduction with carbon. . …… [1] (c) Give two reasons why aluminium is used in the manufacture of aircraft. 1 . …… 2 . …… [2] (d) Give one advantage of recycling aluminium. . …… . …… [1] (e) The table compares the ease of reduction of four metal oxides when heated with carbon. metal oxide ease of reduction aluminium oxide not reduced at 2080 °C nickel(II) oxide reduced at 540 °C titanium(IV) oxide reduced at 1600 °C zinc oxide reduced at 850 °C Put the four metals in order of their reactivity. Put the least reactive metal first. least reactive most reactive [2] (f) Methane is used as a fuel in the extraction of some metals. (i) State the main source of methane. . …… [1] (ii) State one adverse effect of methane on the environment. . …… [1] [Total: 13]

Question

A student investigated the reaction of small pieces of zinc with dilute hydrochloric acid. The hydrochloric acid was in excess. Zn + 2HCl → ZnCl 2 + H2 The rate of reaction is found by measuring the increase in volume of hydrogen gas with time. The results are shown on the graph. 60 50 40 volume of hydrogen gas / cm3 30 20 10 0 0 20 40 60 80 100 120 140 time / s (a) Deduce the time taken from the beginning of the experiment to collect 30 cm3 of hydrogen gas. time = …… s [1] (b) The experiment was repeated using dilute hydrochloric acid of a higher concentration. All other conditions stayed the same. Draw a line on the grid to show how the volume of hydrogen gas changes with time. [2] (c) Describe the effect each of the following has on the rate of reaction of zinc with dilute hydrochloric acid. All other conditions stay the same. ● The reaction is carried out at a lower temperature. . …… ● The reaction is carried out using zinc powder instead of small pieces of zinc. . …… [2] (d) When 0.065 g of zinc is used, 24 cm3 of hydrogen gas is formed. Calculate the mass of zinc needed to produce 96 cm3 of hydrogen gas. mass of zinc = …… g [1] (e) Aqueous ammonia is added to aqueous zinc chloride. Describe the observations when a few drops of aqueous ammonia are added and when excess aqueous ammonia is added. a few drops of aqueous ammonia …… excess aqueous ammonia . …… [2] [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.).