Chemistry 0620/33 October/November 2024: question paper and mark scheme

Question

Fig. 1.1 shows part of the Periodic Table. I II III IV V VI VII VIII H He Li N Ne Al K Ca Cr Fe Zn Rb Ag I Au Fig. 1.1 (a) Answer the following questions using only the elements in Fig. 1.1. Each symbol of the element may be used once, more than once or not at all. Give the symbol of the element that: (i) is in brass …… [1] (ii) produces an orange-red colour in a flame test …… [1] (iii) is a reactant in a fuel cell …… [1] (iv) has an atom with only three occupied electron shells …… [1] (v) forms an ion that gives a red-brown precipitate on addition of aqueous ammonia …… [1] (vi) forms an ion with a charge of 1–. …… [1] (b) Explain why Li, K and Rb have similar chemical properties. …… [2] [Total: 8]

Question

Oxygen, water and ethene have simple molecular structures. (a) (i) State the percentage of oxygen in clean, dry air. …… [1] (ii) Complete Fig. 2.1 to show the dot-and-cross diagram for a molecule of water. Show outer shell electrons only. O H H Fig. 2.1 [2] (iii) Ethene is a small molecule used to make polymers. State the name of the polymer formed from ethene. …… [1] (iv) Complete this sentence about polymers. Polymers are large molecules built up from many smaller molecules called …… . [1] (b) Potassium chloride is an ionic compound. (i) State two physical properties of ionic compounds. 1 …… 2 …… [2] (ii) Choose the correct statement that describes ionic bonding. Tick (✓) one box. It is a weak electrostatic attraction between anions and cations. It is a weak electrostatic attraction between cations. It is a strong electrostatic attraction between anions. It is a strong electrostatic attraction between cations and anions. [1] [Total: 8]

Question

(a) The list shows some gases in a sample of water. Choose from the list the gas that is essential for aquatic life. Draw a circle around your chosen answer. argon hydrogen nitrogen oxygen [1] (b) Polluted water contains harmful substances. Link each harmful substance on the left to the correct effect on the right. One has been done for you. harmful substance effect are toxic to plastics aquatic organisms metal compounds contains harmful such as microbes which mercury(II) chloride cause disease harm aquatic life sewage when eaten lead to nitrates deoxygenation of water [1] Question 3 continues on the next page. (c) Table 3.1 shows the masses of ions, in mg, present in a 1000 cm3 sample of polluted water. Table 3.1 mass of ion in 1000 cm3 name of ion formula of ion of polluted water / mg bromide Br – 0.1 calcium Ca2+ 2.0 chloride Cl – 3.5 hydrogencarbonate HCO3– 12.0 magnesium Mg2+ 0.8 mercury Hg2+ 0.3 nitrate NO3– 0.4 phosphate PO43– 2.0 potassium K + 6.4 silicate SiO32– 4.0 sodium Na+ 10.2 SO42– 0.5 tin Sn2+ 0.2 Answer these questions using the information from Table 3.1. (i) Name the positive ion that has the lowest concentration. …… [1] (ii) State the name of the SO42– ion. …… [1] (iii) Calculate the mass of potassium ions in 125 cm3 of polluted water. mass = …… mg [1] (d) Name two substances used in the treatment of the domestic water supply. For each substance give a reason for its use. substance 1 …… reason …… substance 2 …… reason …… [4] (e) Complete the symbol equation for the reaction of silicon(IV) chloride, SiCl 4, with water. SiCl 4 + ……H2O → SiO2 + ……HCl [2] [Total: 11]

Question

(a) Fig. 4.1 shows the displayed formula of compound A. H H O N C C H H C H O H O H Fig. 4.1 (i) On Fig 4.1 draw a circle around the carboxylic acid functional group. [1] (ii) Deduce the molecular formula of compound A. …… [1] (b) Compound A reacts with ethanol to produce a compound with the molecular formula C5H11NO3. Complete Table 4.1 to calculate the relative molecular mass of C5H11NO3. Table 4.1 relative type of atom number of atoms atomic mass carbon 5 12 5 × 12 = 60 hydrogen 1 nitrogen 14 oxygen 16 relative molecular mass = …… [2] Question 4 continues on the next page. (c) Table 4.2 shows the names, formulae and boiling points of methanol, ethanol, propanol and butanol. Table 4.2 boiling point name formula / °C methanol CH3OH 65 ethanol C2H5OH 79 propanol C3H7OH 98 butanol C4H9OH 117 Use the information in Table 4.2 to answer these questions. (i) Name the homologous series that includes methanol, ethanol, propanol and butanol. …… [1] (ii) Deduce the general formula of this homologous series. …… [1] (iii) State the trend in the boiling point of this homologous series as the number of carbon atoms increases. …… [1] (d) Ethanol can be manufactured by an addition reaction. (i) Name two substances and state two conditions required. substance 1 …… substance 2 …… condition 1 …… condition 2 …… [4] (ii) Draw the displayed formula of ethanol. [1] (iii) Name the toxic gas produced when ethanol undergoes incomplete combustion. …… [1] [Total: 13]

Question

(a) Table 5.1 shows some properties of five halogens. Table 5.1 melting point boiling point atomic volume halogen in °C in °C in cm3 / mol fluorine –220 –188 chlorine –101 –35 22.7 bromine –7 +59 25.6 iodine +114 +184 25.8 astatine +337 32.8 Use the information in Table 5.1 to predict: (i) the melting point of astatine …… [1] (ii) the atomic volume of fluorine …… [1] (iii) the physical state of fluorine at –240 °C. Give a reason for your answer. physical state …… reason …… [2] (b) Aqueous chlorine reacts with aqueous sodium iodide. (i) Complete the word equation for this reaction. sodium …… …… chlorine + → + iodide [2] (ii) Explain why aqueous bromine does not react with aqueous sodium chloride. …… [1] (c) Fluorine reacts with water to produce hydrogen fluoride and oxygen. Complete the symbol equation for this reaction. 2F2 + ……H2O → 4HF + …… [2] (d) Name an anhydrous compound used to test for water. State the colour of the compound after water is added. name of compound …… colour after water is added …… [2] [Total: 11]

Question

This question is about metals. (a) Metals are malleable and ductile. State three other typical physical properties of metals. 1 …… 2 …… 3 …… [3] (b) (i) Complete Table 6.1 to show the number of electrons, neutrons and protons in the calcium atom and copper ion shown. Table 6.1 number of number of number of electrons neutrons protons 48 20Ca 20 65 2+ 29Cu 36 [3] (ii) Write the electronic configuration of the calcium atom. …… [1] (c) Copper is a transition element. Choose the correct statement about transition elements. Tick (✓) one box. They have low densities. They often act as catalysts. They have low melting points. All their compounds are white. [1] (d) Table 6.2 shows the observations when four different metals react with concentrated nitric acid. Table 6.2 metal observations with concentrated nitric acid calcium brown gas produced very rapidly copper brown gas produced slowly manganese brown gas produced rapidly niobium no brown gas seen Put the four metals in order of their reactivity. Put the least reactive metal first. least reactive most reactive [2] (e) Manganese(IV) oxide is reduced by aluminium. 3MnO2 + 4Al → 3Mn + 2Al 2O3 Explain how this equation shows that manganese(IV) oxide is reduced. …… [1] [Total: 11]

Question

This question is about acids, bases and salts. (a) Crystals of zinc chloride can be made by warming excess solid zinc oxide with dilute hydrochloric acid. ZnO(s) + 2HCl (aq) → ZnCl 2(aq) + H2O(……) (i) Complete the symbol equation by adding the state symbol for water at room temperature. [1] (ii) State the method used to separate the excess solid zinc oxide from the reaction mixture. …… [1] (iii) Describe how to make dry crystals of zinc chloride from an aqueous solution of zinc chloride. …… [2] (b) Choose from the list the ion that is present in all acids. Draw a circle around your chosen answer. Cl – H+ O2– OH– [1] (c) The reaction of zinc oxide with hydrochloric acid is exothermic. (i) Define the term exothermic. …… [1] (ii) Fig. 7.1 shows the incomplete reaction pathway diagram for the reaction of zinc oxide with hydrochloric acid. energy progress of reaction Fig. 7.1 Complete Fig. 7.1 by writing these formulae on the diagram: ● ZnO + 2HCl ● ZnCl 2 + H2O. [1] (iii) Explain how Fig. 7.1 shows that the reaction is exothermic. …… [1] (d) Litmus is an acid–base indicator. State the colour of litmus at pH 2 and at pH 12. colour at pH 2 …… colour at pH 12 …… [2] [Total: 10]

Question

(a) A student investigates the reaction of small pieces of magnesium oxide with excess dilute hydrochloric acid of three different concentrations. The time taken for each reaction to finish is recorded. The three concentrations of the acid are: ● 0.4 mol / dm3 ● 0.8 mol / dm3 ● 1.6 mol / dm3. All other conditions stay the same. Table 8.1 shows the time taken for each reaction to finish. Table 8.1 concentration of time taken for the dilute hydrochloric acid reaction to finish in mol / dm3 in s 160 80 320 (i) Complete Table 8.1 by writing the concentrations in the first column. [1] (ii) Describe the effect on the time taken for the reaction to finish when the reaction is carried out at a lower temperature. All other conditions stay the same. …… [1] (iii) Describe the effect on the time taken for the reaction to finish when large pieces of magnesium oxide are used instead of small pieces of magnesium oxide. All other conditions stay the same. …… [1] (b) Molten magnesium chloride is electrolysed using inert electrodes. (i) Name the products at the positive and negative electrodes. product at the positive electrode …… product at the negative electrode …… [2] (ii) Describe the arrangement, motion and separation of the particles in liquid magnesium chloride. arrangement …… motion …… separation …… [3] [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 89–103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 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.).