Chemistry 0620/33 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 H H C C H Cl C H H H H H E F G H H N Na+ I– Na+ I– H C C H H H H I– Na+ I– Na+ H H Na+ I– Na+ I– 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) a compound that is the main constituent of natural gas . …… [1] (ii) the monomer used to produce poly(ethene) . …… [1] (iii) a giant covalent structure . …… [1] (iv) a compound that has a high melting point . …… [1] (v) a waste gas from digestion in animals . …… [1] (vi) a solid at room temperature that conducts electricity when dissolved in water. . …… [1] (b) Complete Fig. 1.2 to show the dot-and-cross diagram for structure B. Show the outer electron shells only. H Cl Fig. 1.2 [2] [Total: 8]

Question

(a) Intracellular fluid is the solution between the cells in the human body. Table 2.1 shows the masses, in mg, of some ions in 100 cm3 of intracellular fluid. Table 2.1 mass of ion in 100 cm3 name of ion formula of ion of intracellular fluid / mg calcium Ca2+ 6 chloride Cl – 7 hydrogencarbonate HCO3– 49 phosphate PO43– 547 magnesium Mg2+ 31 potassium K+ 624 sodium Na+ 23 sulfate SO42– 96 Answer these questions using information from Table 2.1. (i) Name the positive ion that is present in the lowest concentration. . …… [1] (ii) Name the ion that contains an element in Group IV of the Periodic Table. . …… [1] (b) Describe a test for sulfate ions. test . …… . …… observations …… . …… [2] (c) Small amounts of ammonium ions and chloride ions are formed in some cells of the body. State the formula of the compound formed from ammonium ions and chloride ions. . …… [1] (d) Choose from the list the salt that is insoluble in water. Tick (✓) one box. copper(II) nitrate lead(II) chloride potassium nitrate sodium chloride [1] (e) Table 2.2 shows some properties of the Group I metals. Table 2.2 hardness observations on metal / MPa reaction with water bubbles form very slowly lithium 5.0 and no flame bubbles form very slowly sodium 0.69 and no flame bubbles form very rapidly potassium and flame rubidium 0.22 Use the information in Table 2.2 to: ● predict the hardness of potassium . …… ● describe the observations when rubidium reacts with water. . …… [2] (f) Sodium reacts with hydrogen to produce sodium hydride, NaH. Complete the symbol equation for this reaction. 2Na + …… → ……NaH [2] [Total: 10]

Question

(a) Molten calcium bromide is electrolysed. (i) Define the term electrolysis. . …… . …… [2] (ii) Name an inert metal that can be used for the electrodes. . …… [1] (iii) Name the product formed at each electrode. positive electrode . …… negative electrode …… [2] (b) Calcium reacts with water. An alkaline solution is produced. (i) Name the ion which causes a solution to be alkaline. . …… [1] (ii) Choose the pH value of an alkaline solution. Draw a circle around your chosen answer. pH 1 pH 5 pH 7 pH 9[1] (iii) Dilute hydrochloric acid is added to a solution of litmus in alkaline solution until the acid is in excess. State the colour change of the litmus. (c) Calcium carbonate is added to the blast furnace in the production of iron. Calcium carbonate breaks down when heated to produce calcium oxide and a gas that turns limewater milky. (i) Name the gas that turns limewater milky. . …… [1] (ii) Name the type of chemical reaction that takes place when calcium carbonate is heated. . …… [1] [Total: 11]

Question

(a) Chlorophyll is a coloured compound found in plants. Chlorophyll is needed for photosynthesis. (i) Complete the word equation for photosynthesis. carbon + water → + dioxide …… …… [2] (ii) State one other condition that is essential for photosynthesis. . …… [1] (b) Several other coloured compounds are found in plant leaves. A student extracts a mixture of coloured compounds from a plant leaf. Fig. 4.1 shows the apparatus used to separate the coloured compounds. filter paper mixture of coloured compounds base line solution of methyl ethanoate in ethanoic acid Fig. 4.1 (i) Name this method of separation. . …… [1] (ii) Suggest why the base line is drawn in pencil and not in ink. . …… [1] (iii) The liquid used to separate the coloured compounds is a solution of methyl ethanoate in ethanoic acid. State the meaning of the term solution. . …… . …… [1] (c) Fig. 4.2 shows the displayed formula of a compound found in plant cells. O O H C O H C O H C C H H O H C H C O O H Fig. 4.2 On Fig. 4.2, draw a circle around the alcohol functional group. [1] [Total: 7]

Question

(a) An atom of phosphorus is represented by the symbol shown. 15P 31 Describe this atom of phosphorus in terms of: ● the position of the electrons, neutrons and protons in the atom . …… . …… ● the number of neutrons and the number of protons . …… . …… ● the electronic configuration. . …… [5] (b) Complete the symbol equation for the reaction of phosphorus with oxygen. ……P + ……O2 → P4O10[2] (c) Fig. 5.1 shows the displayed formula of a compound of phosphorus. Cl Cl N P Cl P N Cl N P Cl Cl Fig. 5.1 Deduce the molecular formula of this compound. . …… [1] (d) Another compound of phosphorus has the formula Na3PO4. Complete Table 5.1 to calculate the relative formula mass of Na3PO4. Table 5.1 relative type of atom number of atoms atomic mass sodium 3 23 3 × 23 = 69 phosphorus 31 oxygen 16 relative formula mass = …… [2] (e) Phosphates in rivers can cause deoxygenation of water. State one source of phosphates in river water. . …… [1] [Total: 11]

Question

Dilute hydrochloric acid reacts with small pieces of calcium carbonate. 2HCl (aq) + CaCO3(s) → CaCl 2(aq) + H2O(l) + CO2(g) (a) State the meaning of the state symbol (aq). . …… [1] (b) Fig. 6.1 shows how the mass of small pieces of calcium carbonate changes as the reaction proceeds. The calcium carbonate is in excess. 10 8 6 mass of calcium carbonate /g 4 2 0 0 1 2 3 4 5 6 time / minutes Fig. 6.1 (i) Deduce the mass of calcium carbonate two minutes from the start of the reaction. . …… [1] (ii) Explain how the graph shows that the calcium carbonate is in excess. . …… [1] (iii) The experiment is repeated at a higher temperature. All other conditions stay the same. Draw a line on Fig. 6.1 to show how the mass of calcium carbonate changes at a higher temperature as the time increases. [2] (c) (i) Describe the effect, if any, on the rate of reaction when large pieces of calcium carbonate are used instead of small pieces of calcium carbonate. All other conditions stay the same. . …… [1] (ii) Increasing the concentration of dilute hydrochloric acid increases the rate of reaction of dilute hydrochloric acid with calcium carbonate. Choose the correct unit of concentration from the list. Draw a circle around your chosen answer. dm3 / g g / dm2 mol / dm mol / dm3[1] (d) Concentrated hydrochloric acid gives off hydrogen chloride gas. Hydrogen chloride is an acidic gas that turns damp universal indicator paper red. A long glass tube is set up as shown in Fig. 6.2. concentrated universal hydrochloric acid indicator paper Fig. 6.2 At first, the universal indicator paper does not change colour. The universal indicator paper turns red after a short time. Explain these results in terms of kinetic particle theory. . …… . …… . …… . …… [3] (e) Hydrogen chloride breaks down to form hydrogen and chlorine at 1500 °C. The reaction in endothermic. State the meaning of the term endothermic. . …… [1] [Total: 11]

Question

Chromium and iron are transition elements. They are ductile and have high melting and boiling points. (a) State three other physical properties of chromium. 1 . …… 2 . …… 3 . …… [3] (b) The formula for rust is Fe2O3•xH2O. (i) State the chemical name of rust. . …… [2] (ii) An iron object is coated with plastic. Explain how this prevents the iron from rusting. . …… . …… [2] (c) Chromium behaves as a typical metal when it reacts with sulfuric acid. Complete the word equation for this reaction. sulfuric …… chromium + → + acid …… [2] (d) The list shows five metals. aluminium calcium copper iron zinc Put these metals in order of their reactivity. Put the most reactive metal at the top. most reactive least reactive [2] (e) Zinc can be produced by heating zinc oxide with carbon. ZnO + C → Zn + CO Describe how this equation shows that zinc oxide is reduced. . …… . …… [1] [Total: 12]

Question

This question is about hydrocarbons. (a) Table 8.1 shows the names, formulae and boiling points of methane, ethane, propane and butane. Table 8.1 name formula boiling point / °C methane CH4 –164 ethane C 2H 6 –88 propane C3 H 8 –42 butane C4H10 0 Use the information in Table 8.1 to answer these questions. (i) Name the homologous series that includes methane, ethane, propane and butane. . …… [1] (ii) State the trend in the boiling point of this homologous series as the number of carbon atoms increases. . …… [1] (iii) Deduce the general formula of this homologous series. . …… [1] (b) Complete the word equation for the complete combustion of ethane. ethane + oxygen → + [2] (c) Long-chain hydrocarbons can be cracked to produce alkenes and hydrogen. (i) State two conditions for cracking. 1 . …… 2 . …… [2] (ii) The diesel oil fraction from the fractional distillation of petroleum can be used for cracking. Give one other use of the diesel oil fraction. . …… [1] (d) Alkene molecules can react together to produce polymers. Define the term polymer. . …… . …… [2] [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 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.).