IGCSE Chemistry Paper3a 2006

Centre Number Candidate Number Name UNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS International General Certificate of Secondary Education CHEMISTRY 0620/03 Paper 3 May/June 2006 1 hour 15 minutes Candidates answer on the Question Paper. No Additional Materials are required. READ THESE INSTRUCTIONS FIRST Write your Centre number, candidate number and name in the spaces at the top of this page. Write in dark blue or black pen. You may use a pencil for any diagrams, graphs or rough working. Do not use staples, paper clips, highlighters, glue or correction fluid. Answer all questions. A copy of the Periodic Table is printed on page 16. At the end of the examination, fasten all your work securely together. The number of marks is given in brackets [ ] at the end of each question or part question. For Examiner’s Use 1 2 3 4 5 6 7 Total This document consists of 16 printed pages. IB06 06_0620_03/4RP  UCLES 2006 [Turn over 2 © UCLES 2006 0620/03/M/J/06 For Examiner's Use 1 Iron is a transition element. (a) Which of the following statements about transition elements are correct? Tick three boxes. The metals are highly coloured e.g. yellow, green, blue. The metals have low melting points. Their compounds are highly coloured. Their compounds are colourless. The elements and their compounds are often used as catalysts. They have more than one oxidation state. [3] (b) (i) In which Period in the Periodic Table is iron to be found? [1] (ii) Use the Periodic Table to work out the number of protons and the number of neutrons in one atom of iron. number of protons = number of neutrons = [1] (c) Iron is extracted in a blast furnace. The list below gives some of the substances used or formed in the extraction. carbon monoxide coke iron ore limestone slag (i) Which substance is a mineral containing largely calcium carbonate? [1] (ii) Which substance is formed when impurities in the ore react with calcium oxide? [1] (iii) Which substance is also called hematite? [1] 3 © UCLES 2006 0620/03/M/J/06 [Turn over For Examiner's Use (d) State two functions of the coke used in the blast furnace. [2] (e) Most of the iron is converted into mild steel or stainless steel. Give one use for each. mild steel stainless steel [2] 4 © UCLES 2006 0620/03/M/J/06 For Examiner's Use 2 Some reactions of metals W, X, Y and Z are given below. metal reaction with water reaction with dilute hydrochloric acid W A few bubbles form slowly in cold water. Vigorous reaction. Gas given off. X Vigorous reaction. Metal melts. Gas given off. Explosive reaction. Should not be attempted. Y No reaction. No reaction. Z Does not react with cold water. Hot metal reacts with steam. Steady fizzing. (a) Arrange these metals in order of reactivity. most reactive least reactive [2] (b) Which of these metals could be (i) magnesium, [1] (ii) copper? [1] 5 © UCLES 2006 0620/03/M/J/06 [Turn over For Examiner's Use (c) The equation for the reaction of X with cold water is given below. 2X(s) + 2H2O(l) 2XOH(aq) + H2(g) (i) Describe the test you would use to show that the gas evolved is hydrogen. [1] (ii) How could you show that the water contained a compound of the type XOH? [2] (iii) In which group of the Periodic Table does metal X belong? [1] (iv) The ore of X is its chloride. Suggest how metal X could be extracted from its chloride. [2] 6 © UCLES 2006 0620/03/M/J/06 For Examiner's Use 3 (a) Four bottles were known to contain aqueous ammonia, dilute hydrochloric acid, sodium hydroxide solution and vinegar, which is dilute ethanoic acid. The bottles had lost their labels. The pH values of the four solutions were 1, 4, 10 and 13. Complete the table. solution pH aqueous ammonia dilute hydrochloric acid sodium hydroxide solution vinegar [2] (b) The following apparatus was set up to investigate the electrical conductivity of dilute acids. + _ carbon anode bulb/lamp carbon cathode dilute sulphuric acid bubbles of oxygen gas bubbles of hydrogen gas Dilute sulphuric acid is a strong acid. If it was replaced by a weak acid, what two differences in the observations would you expect to make? [2] (c) When nitric acid is added to water the following reaction occurs. HNO3 + H2O -3 NO + H3O+ Give the name and the formula of the particle which is transferred from nitric acid to water. name formula [2] 7 © UCLES 2006 0620/03/M/J/06 [Turn over For Examiner's Use (d) This question is concerned with the following oxides. aluminium oxide Al2O3 calcium oxide CaO carbon dioxide CO2 carbon monoxide CO magnesium oxide MgO sulphur dioxide SO2 (i) Which of the above oxides will react with hydrochloric acid but not with aqueous sodium hydroxide? [1] (ii) Which of the above oxides will react with aqueous sodium hydroxide but not with hydrochloric acid? [1] (iii) Which of the above oxides will react both with hydrochloric acid and with aqueous sodium hydroxide? [1] (iv) Which of the above oxides will react neither with hydrochloric acid nor with aqueous sodium hydroxide? [1] 8 © UCLES 2006 0620/03/M/J/06 For Examiner's Use 4 The first three elements in Group IV are carbon, silicon, germanium. (a) The element germanium has a diamond-type structure. Describe the structure of germanium. A diagram is acceptable. [2] (b) Unlike diamond, graphite is soft and is a good conductor of electricity. (i) Explain why graphite has these properties. [3] (ii) Give a use of graphite that depends on one of these properties. property use [1] (c) Carbon dioxide and silicon(IV) oxide have similar formulae but different types of structure. (i) Give the formulae of these oxides. [1] (ii) How are their structures different? [2] (d) All these elements form compounds with hydrogen called hydrides. The saturated hydrides of carbon are the alkanes. Predict the formula of the hydride of germanium which contains two germanium atoms. [1] 9 © UCLES 2006 0620/03/M/J/06 [Turn over For Examiner's Use 5 Sulphuric acid is made by the Contact process in the following sequence of reactions. sulphur sulphur dioxide sulphur trioxide sulphuric acid (a) (i) How is sulphur dioxide made from sulphur? [1] (ii) Sulphur dioxide has other uses. Why is it used in the manufacture of paper? [1] (iii) How does it preserve food? [1] (b) The equation for a stage of the Contact process is 2SO2 + O2 2SO3 The percentage of sulphur trioxide in the equilibrium mixture varies with temperature. percentage of sulphur trioxide temperature (i) How does the percentage of sulphur trioxide in the equilibrium mixture vary as the temperature increases? Circle the correct answer. increases stays the same decreases [1] (ii) Is the forward reaction in the equilibrium 2SO2 + O2 2SO3 exothermic or endothermic? Give a reason for your choice. [2] 10 © UCLES 2006 0620/03/M/J/06 For Examiner's Use (iii) Explain, mentioning both rate and percentage yield, why the temperature used in the Contact process is 450°C. [2] (iv) Describe how the sulphur trioxide is changed into concentrated sulphuric acid. [2] 11 © UCLES 2006 0620/03/M/J/06 [Turn over For Examiner's Use 6 (a) Exothermic reactions produce heat energy. An important fuel is methane, natural gas. The equation for its combustion is as follows. CH4 + 2O2 CO2 + 2H2O (i) In chemical reactions bonds are broken and new bonds are formed. Using this reaction give an example of a bond that is broken, a bond that is formed. [2] (ii) Explain, using the idea of bonds forming and breaking, why this reaction is exothermic, that is it produces heat energy. [2] (b) Some radioactive isotopes are used as nuclear fuels. (i) Give the symbol and the nucleon number of an isotope that is used as a nuclear fuel. [2] (ii) Give another use of radioactive isotopes. [1] 12 © UCLES 2006 0620/03/M/J/06 For Examiner's Use (c) Cell reactions are both exothermic and redox. They produce electrical energy as well as heat energy. (i) The diagram shows a simple cell. V zinc electrode becomes thinner iron electrode bubbles of hydrogen form dilute sulphuric acid voltmeter Which substance in this cell is the reductant and which ion is the oxidant? reductant oxidant [2] (ii) How could the voltage of this cell be increased? [1] (iii) What is the important large scale use, relating to iron and steel, of this type of cell reaction? [1] 13 © UCLES 2006 0620/03/M/J/06 [Turn over For Examiner's Use (d) Cells can be set up with inert electrodes and the electrolytes as oxidant and reductant. V voltmeter carbon electrode (inert) carbon electrode (inert) potassium manganate(VII) (aq) potassium iodide (aq) salt bridge (allows ions to move from one beaker to another) electron flow The potassium manganate(VII) is the oxidant and the potassium iodide is the reductant. (i) Describe the colour change that would be observed in the left hand beaker. [2] (ii) Write an ionic equation for the reaction in the right hand beaker. [2] 14 © UCLES 2006 0620/03/M/J/06 For Examiner's Use 7 The fractional distillation of crude oil usually produces large quantities of the heavier fractions. The market demand is for the lighter fractions and for the more reactive alkenes. The heavier fractions are cracked to form smaller alkanes and alkenes as in the following example. C8H18 C4 H10 + C4H8 octane butane butenes (a) (i) Write a different equation for the cracking of octane. C8H18 + [1] (ii) The cracking of octane can produce isomers with the molecular formula C4H8. Draw the structural formulae of two of these isomers. [2] (b) (i) Give the essential condition for the reaction between chlorine and butane. [1] (ii) What type of reaction is this? [1] (iii) This reaction produces a mixture of products. Give the names of two products that contain four carbon atoms per molecule. and [2] 15 Permission to reproduce items where third-party owned material protected by copyright is included has been sought and cleared where possible. Every reasonable effort has been made by the publisher (UCLES) to trace copyright holders, but if any items requiring clearance have unwittingly been included, the publisher will be pleased to make amends at the earliest possible opportunity. University of Cambridge International Examinations is part of the University of Cambridge Local Examinations Syndicate (UCLES), which is itself a department of the University of Cambridge. © UCLES 2006 0620/03/M/J/06 For Examiner's Use (c) Alkenes are more reactive than alkanes and are used to make a range of organic chemicals. Propene, CH3–CH=CH2, is made by cracking. Give the structural formula of the addition product when propene reacts with the following. (i) water [1] (ii) bromine [1] (d) Propene reacts with hydrogen iodide to form 2 -iodopropane. CH3−CH=CH2 + HI CH3−CHI−CH3 1.4 g of propene produced 4.0 g of 2 -iodopropane. Calculate the percentage yield. moles of CH3–CH=CH2 reacted = maximum moles of CH3–CHI–CH3 that could be formed = mass of one mole of CH3–CHI–CH3 = 170 g maximum mass of 2 -iodopropane that could be formed = percentage yield % [4] 16 © UCLES 2006 0620/03/M/J/06 Group 140 Ce Cerium 58 141 Pr Praseodymium 59 144 Nd Neodymium 60 Pm Promethium 61 150 Sm Samarium 62 152 Eu Europium 63 157 Gd Gadolinium 64 159 Tb Terbium 65 162 Dy Dysprosium 66 165 Ho Holmium 67 167 Er Erbium 68 169 Tm Thulium 69 173 Yb Ytterbium 70 175 Lu Lutetium 71 232 Th Thorium 90 Pa Protactinium 91 238 U Uranium 92 Np Neptunium 93 Pu Plutonium 94 Am Americium 95 Cm Curium 96 Bk Berkelium 97 Cf Californium 98 Es Einsteinium 99 Fm Fermium 100 Md Mendelevium 101 No Nobelium 102 Lr Lawrencium 103 1 H Hydrogen 1 7 Li Lithium 3 23 Na Sodium 11 24 Mg Magnesium 12 40 Ca Calcium 20 45 Sc Scandium 21 48 Ti Ti tanium 22 51 V Vanadium 23 52 Cr Chromium 24 55 Mn Manganese 25 56 Fe Iron 26 59 Co Cobalt 27 59 Ni Nickel 28 64 Cu Copper 29 65 Zn Zinc 30 70 Ga Gallium 31 27 Al Aluminium 13 11 B Boron 5 12 C Carbon 6 14 N Nitrogen 7 16 O Oxygen 8 19 F Fluorine 9 28 Si Silicon 14 31 P Phosphorus 15 32 S Sulphur 16 35.5 Cl Chlorine 17 40 Ar Argon 18 20 Ne Neon 10 4 He Helium 2 73 Ge Germanium 32 75 As Arsenic 33 79 Se Selenium 34 80 Br Bromine 35 84 Kr Krypton 36 39 K Potassium 19 88 Sr Strontium 38 89 Y Yttrium 39 91 Zr Zirconium 40 93 Nb Niobium 41 96 Mo Molybdenum 42 Tc Technetium 43 101 Ru Ruthenium 44 103 Rh Rhodium 45 106 Pd Palladium 46 108 Ag Silver 47 11 2 Cd Cadmium 48 115 In Indium 49 11 9 Sn Tin 50 122 Sb Antimony 51 128 Te Tellurium 52 127 I Iodine 53 131 Xe Xenon 54 137 Ba Barium 56 139 La Lanthanum 57 * 178 Hf Hafnium 72 181 Ta Tantalum 73 184 W Tungsten 74 186 Re Rhenium 75 190 Os Osmium 76 192 Ir Iridium 77 195 Pt Platinum 78 197 Au Gold 79 201 Hg Mercury 80 204 Tl Thallium 81 207 Pb Lead 82 209 Bi Bismuth 83 Po Polonium 84 At Astatine 85 Rn Radon 86 Fr Francium 87 227 Ac Actinium 89 9 Be Beryllium 4 III III IV V VI VII 0 85 Rb Rubidium 37 133 Cs Caesium 55 226 Ra Radium 88 The volume of one mole of any gas is 24 dm3 at room temperature and pressure (r.t.p.). a X b a = relative atomic mass X = atomic symbol b = proton (atomic) number Key *58-71 Lanthanoid series 90-103 Actinoid series DATA SHEET The Periodic Table of the Elements