Chemistry 0620/32 February/March 2020: question paper and mark scheme

Question

(a) A list of compounds is shown. aluminium oxide calcium bromide calcium oxide ethane ethene hydrogen chloride methane nitrogen dioxide potassium iodide potassium manganate(VII) sodium chloride Answer the following questions using only the compounds in the list. Each compound may be used once, more than once or not at all. Which compound: (i) when in acidified solution, is used to test for sulfur dioxide . …… [1] (ii) is the main constituent of natural gas . …… [1] (iii) when dissolved in water, gives a yellow precipitate on addition of acidified aqueous silver nitrate . …… [1] (iv) is used in flue gas desulfurisation to neutralise acidic gases . …… [1] (v) is a reactant used in the manufacture of ethanol? . …… [1] (b) What is the meaning of the term compound ? . …… . …… [2] (c) Complete the electronic structure of a molecule of hydrogen chloride. Show only the outer shell electrons. H Cl [2] [Total: 9]

Question

Iron is extracted by heating a mixture of coke (carbon), limestone and iron ore in air in a blast furnace. A diagram of the blast furnace is shown. coke (carbon) + limestone + iron ore firebrick lining air in slag molten iron (a) Name the ore of iron added to the blast furnace. . …… [1] (b) The impurities in the iron ore are removed as slag. (i) What information in the diagram shows that slag is less dense than molten iron? . …… [1] (ii) Which one of the substances added to the blast furnace helps to remove the impurities? Explain how it does this. substance …… explanation …… . …… . …… [3] (c) Hot air is blown into the blast furnace. Explain why. . …… . …… [1] (d) The chemical equation for one of the reactions in the blast furnace is shown. Fe2O3 + 3CO → 2Fe + 3CO2 (i) How does this equation show that Fe2O3 has been reduced? . …… [1] (ii) When 16.0 g of Fe2O3 react with excess carbon monoxide, 11.2 g of iron are produced. Calculate the mass of iron produced when 4.0 g of Fe2O3 react with excess carbon monoxide. mass of iron = …… g [1] (e) An isotope of iron is shown. 26Fe 58 Deduce the number of electrons, protons and neutrons in an atom of this isotope of iron. number of electrons . …… number of protons …… number of neutrons …… [3] (f) Iron is a transition element. Which two of these statements about iron are correct? Tick two boxes. Iron forms coloured compounds. Iron can act as a catalyst. Iron is brown when freshly cut. Iron has a low density. Iron has a low melting point. [2] [Total: 13]

Question

Water is essential for many industrial processes. (a) State one use of water in industry. . …… [1] (b) What is the pH of pure water? Draw a circle around the correct answer. pH 0 pH 6 pH 7 pH 14[1] (c) Filtration and chlorination are two of the steps used in water treatment. Describe the purpose of each of these steps. filtration …… . …… chlorination …… . …… [2] (d) The changes of state of water are shown. A boiling ice water steam freezing B Give the names of the changes of state represented by A and B. A …… B …… [2] (e) The table compares the reactions of four metals with both steam and dilute hydrochloric acid. reaction with observation with metal steam at 200 °C dilute hydrochloric acid copper no reaction no bubbles formed magnesium rapid reaction bubbles form rapidly nickel no reaction bubbles form slowly zinc rapid reaction bubbles form slowly Put the four metals in order of their reactivity. Put the least reactive metal first. least reactive most reactive [2] [Total: 8]

Question

Angelic acid and ethanoic acid are both carboxylic acids. The structure of angelic acid is shown. H H C H H C H C C C O H H O H (a) (i) On the structure of angelic acid, draw a circle around the functional group that shows that it is a carboxylic acid. [1] (ii) Deduce the formula of angelic acid to show the number of carbon, hydrogen and oxygen atoms. . …… [1] (iii) Angelic acid is an unsaturated compound. Describe a chemical test to distinguish between an unsaturated and a saturated compound. test . …… result with unsaturated compound . …… result with saturated compound . …… [3] (b) The formula of ethanoic acid is C2H4O2. Complete the table to calculate the relative molecular mass of ethanoic acid. Use the Periodic Table to help you. type number relative of atom of atoms atomic mass carbon 2 12 2 × 12 = 24 hydrogen oxygen 16 relative molecular mass = …… [2] (c) Ethanoic acid can be reduced to ethanol. Complete the structure of ethanol to show all of the atoms and all of the bonds. H H C C H [1] (d) Ethanol can be manufactured by fermentation. Describe the process of fermentation to include: ●● the names of the reactants and catalyst . …… . …… ●● the conditions required . …… . …… . …… ●● the name of the process used to separate the ethanol from the rest of the reaction mixture. . …… [4] [Total: 12]

Question

The table shows some properties of four metals in Group I of the Periodic Table. melting point boiling point relative electrical metal / °C / °C conductivity sodium 98 883 potassium 63 760 14 rubidium 686 8 caesium 29 669 5 (a) Complete the table to estimate: ●● the melting point of rubidium ●● the relative electrical conductivity of sodium. [2] (b) What is the physical state of caesium at 20 °C? Give a reason for your answer. . …… . …… . …… [2] (c) Describe the trend in the boiling points of the Group I metals. . …… [1] (d) When potassium reacts with water, a coloured flame is seen and a gas is produced that pops with a lighted splint. (i) Complete the chemical equation for this reaction. ……K + 2H2O → 2KOH + …… [2] (ii) State the colour of the flame when potassium reacts with water. . …… [1] (iii) The solution formed is alkaline. Describe how you can use universal indicator solution to determine the pH of the solution. . …… . …… [2] [Total: 10]

Question

This question is about the reactions of magnesium with nitric acid. (a) The equation for the reaction of magnesium with concentrated nitric acid is shown. Mg + 4HNO3 → Mg(NO3)2 + 2NO2 + 2H2O (i) The reaction is exothermic. What is the meaning of the term exothermic? . …… [1] (ii) Which word best describes the compound Mg(NO3)2? Draw a circle around the correct answer. acid base oxide salt[1] (iii) Oxides of nitrogen are formed when fossil fuels are burned. What type of chemical reaction occurs when fossil fuels are burned? Draw a circle around the correct answer. combustion cracking fermentation neutralisation[1] (iv) Oxides of nitrogen dissolve in rain water to form acid rain. State one adverse effect of acid rain on buildings. . …… [1] (b) When very dilute nitric acid reacts with magnesium powder, hydrogen is produced. (i) Describe a practical method for investigating the rate of this reaction. . …… . …… . …… . …… [3] (ii) What effect would each of the following have on the rate of this reaction? ●● Larger pieces of magnesium are used instead of magnesium powder. All other conditions stay the same. . …… ●● The temperature of the reaction mixture is increased. All other conditions stay the same. . …… [2] [Total: 9]

Question

(a) The electrolysis of dilute sulfuric acid produces gases at both electrodes. (i) The incomplete apparatus is shown. electrolyte + – power supply Complete the diagram by: ●● labelling the anode and cathode ●● adding connecting wires ●● showing how the gases are collected. [3] (ii) Name the products formed at each electrode. positive electrode . …… negative electrode …… [2] (b) Carbon dioxide is produced when sulfuric acid reacts with sodium carbonate. Name the two other products which are formed. …… and . …… [2] (c) Describe the test for carbon dioxide. test . …… observations …… [2] (d) Carbon dioxide is a greenhouse gas. State one effect of greenhouse gases on the environment. . …… [1] [Total: 10]

Question

(a) The structures of four substances C, D, E and F, are shown. C D E F H H Na+ Cl – Na+ Cl – H H C C Cl – Na + Cl – Na + H H C H H H H Na+ Cl – Na+ Cl – H H H H Cl – Na+ Cl – Na+ C C H H H H H H (i) Which one of these substances, C, D, E or F, is a gas at room temperature? . …… [1] (ii) What type of bonding is present in substance E? . …… [1] (iii) Which one of these substances, C, D, E or F, is soluble in water? . …… [1] (iv) Which one of these substances, C, D, E or F, conducts electricity when solid? . …… [1] (b) The halogens have molecules containing two atoms. What is the name for molecules containing only two atoms? . …… [1] (c) The reaction of iodine with hydrogen is shown. I2 + H2 2HI What is the meaning of the symbol ? . …… [1] (d) Iodine is formed when chlorine reacts with aqueous potassium iodide. (i) Complete the chemical equation for this reaction. …… + 2KI → I2 + ……KCl[2] (ii) When aqueous iodine is mixed with aqueous potassium chloride, there is no reaction. Suggest, in terms of chemical reactivity, why there is no reaction. . …… [1] [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 89–103 104 105 106 107 108 109 110 111 112 114 116 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.).