Chemistry 0620/21 May/June 2020: question paper and mark scheme

Question

A mixture of ice and water is left to stand and the ice melts. Which row describes what happens as the ice is melting? temperature of mixture energy changes A increases average kinetic energy of particles increases B increases energy is used to overcome attractive forces C stays the same average kinetic energy of particles increases D stays the same energy is used to overcome attractive forces

Question

Which piece of apparatus should be used to measure exactly 21.4 cm3 of water? A 25 cm3 beaker B 25 cm3 pipette C 50 cm3 burette D 50 cm3 measuring cylinder

Question

The chromatogram for an unknown dye is shown. solvent front 12 cm 15 cm 9 cm 2 cm What is the Rf value of the dye? A 0.60 B 0.64 C 0.75 D 0.82

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The atomic number and nucleon number of a potassium atom are shown. potassium atom atomic number 19 nucleon number 39 How many protons, neutrons and electrons are in a potassium ion, K+? protons neutrons electrons A 19 20 18 B 19 20 20 C 20 19 18 D 20 19 19

Question

The electronic structures of two atoms, P and Q, are shown. P Q P and Q combine together to form a compound. What is the type of bonding in the compound and what is the formula of the compound? type of bonding formula A ionic PQ B ionic PQ2 C covalent PQ2 D covalent PQ

Question

Which row contains a description of metallic bonding and a property that is explained by reference to metallic bonding? description of property explained by metallic bonding metallic bonding A a lattice of negative ions a metal will react with an in a sea of electrons acid, producing hydrogen B a lattice of negative ions a piece of a metal can be in a sea of electrons moulded into different shapes C a lattice of positive ions a metal will react with an in a sea of electrons acid, producing hydrogen D a lattice of positive ions a piece of a metal can be in a sea of electrons moulded into different shapes

Question

Which statement explains why methane has a lower boiling point than water? A Methane has weaker covalent bonds than water. B Methane has weaker attractive forces than water. C Methane molecules are heavier than water molecules. D Methane molecules have more bonds than water molecules.

Question

A solution of iron(III) sulfate reacts with aqueous sodium hydroxide to form a red–brown precipitate. What is the balanced equation, including state symbols, for the reaction? A FeSO4(aq) + 2NaOH(aq) → Fe(OH)2(s) + Na2SO4(aq) B FeSO4(l) + 2NaOH(l) → Fe(OH)2(s) + Na2SO4(l) C Fe2(SO4)3(aq) + 6NaOH(aq) → 2Fe(OH)3(s) + 3Na2SO4(aq) D Fe2(SO4)3(l) + 6NaOH(aq) → 2Fe(OH)3(s) + 3Na2SO4(l)

Question

The Haber process is a reversible reaction. N2(g) + 3H2(g) 2NH3(g) The reaction has a 30% yield of ammonia. Which volume of ammonia gas, NH3, measured at room temperature and pressure, is obtained by reacting 0.75 moles of hydrogen with excess nitrogen? A 3600 cm3 B 5400 cm3 C 12 000 cm3 D 18 000 cm3

Question

Dilute aqueous sodium chloride is electrolysed using platinum electrodes. What is the half-equation for the reaction at the cathode? A 2H+ + 2e– → H2 B Na+ + e– → Na C 2Cl – → Cl 2 + 2e– D 4OH– → 2H2O + O2 + 4e–

Question

The electrolysis of aqueous copper(II) sulfate, using inert electrodes, is shown. + – aqueous copper(II) sulfate Which statement about a reaction at an electrode is correct? A Copper ions gain electrons at the negative electrode. B Copper ions gain electrons at the positive electrode. C Hydrogen ions gain electrons at the negative electrode. D Hydrogen ions gain electrons at the positive electrode.

Question

The equation for the complete combustion of methane gas is shown. CH4(g) + 2O2(g) → CO2(g) + 2H2O(g) Bond energies are shown. bond energy bond in kJ / mol C–H 412 H–O 463 C=O 743 O=O 498 What is the overall energy change, in kJ / mol, for the above reaction? A –1192 B –694 C +694 D +1192

Question

Which statements about hydrogen fuel cells are correct? 1 Water is formed as the only waste product. 2 Both water and carbon dioxide are formed as waste products. 3 The overall reaction is 2H2 + O2 → 2H2O. 4 The overall reaction is endothermic. A 1 and 3 B 1 and 4 C 2 and 3 D 2 and 4

Question

Which diagram represents a chemical change? A B C D

Question

The rate of reaction between calcium carbonate chips and hydrochloric acid is studied by collecting the volume of gas released in one minute at different temperatures. A graph of rate of reaction against temperature is shown. 80 70 60 50 rate of reaction 40 cm3 / min 30 20 10 0 0 10 20 30 40 50 60 temperature / °C Which statement fully explains why increasing the temperature has this effect on the rate? A The kinetic energy of the particles increases so the collisions are harder. B The number of collisions between particles increases. C The activation energy needed for the particles to react is reduced. D There are more frequent collisions between particles with enough energy to react.

Question

The equation shows the equilibrium between dinitrogen tetroxide, N2O4, and nitrogen dioxide, NO2. The colours of the reactant and product are also shown. N2O4(g) 2NO2(g) colourless brown The forward reaction is endothermic. Which statement is not correct? A At equilibrium the concentrations of the reactant and the product are constant. B At equilibrium the rate of the forward reaction is equal to the rate of the reverse reaction. C When the pressure is increased a darker brown colour is seen. D When the temperature is increased a darker brown colour is seen.

Question

The equations for two reactions of iodide ions are shown. reaction 1 2I–(aq) + H2O2(aq) → I2(aq) + 2OH–(aq) reaction 2 I–(aq) + Ag+(aq) → AgI(s) Which statement is correct? A Both reactions are redox reactions. B Neither reaction is a redox reaction. C Only reaction 1 is a redox reaction. D Only reaction 2 is a redox reaction.

Question

The graph shows how the pH of a solution changes as an acid is added to an alkali. acid + alkali → salt + water Which letter represents the area of the graph where both acid and salt are present? A 14 B C pH 7 D 0 volume of acid added

Question

Which statement describes a weak acid? A It is a proton acceptor and is fully ionised in aqueous solution. B It is a proton acceptor and is partially ionised in aqueous solution. C It is a proton donor and is fully ionised in aqueous solution. D It is a proton donor and is partially ionised in aqueous solution.

Question

The apparatus shown is used to prepare aqueous copper(II) sulfate. filter paper stirrer excess of solid X solid X Y aqueous copper(II) sulfate heat What are X and Y? X Y A copper aqueous iron(II) sulfate B copper(II) chloride dilute sulfuric acid C copper(II) oxide dilute sulfuric acid D sulfur aqueous copper(II) chloride

Question

Lead(II) sulfate is an insoluble salt. Which method is suitable for obtaining solid lead(II) sulfate? A Mix aqueous lead(II) nitrate and aqueous potassium sulfate, heat to evaporate all of the water, collect the solid and then wash and dry it. B Mix aqueous lead(II) nitrate and aqueous potassium sulfate, filter, collect the filtrate, crystallise, then wash and dry the crystals. C Mix aqueous lead(II) nitrate and dilute sulfuric acid, filter, then wash and dry the residue. D Titrate aqueous lead(II) hydroxide with dilute sulfuric acid, crystallise, then wash and dry the crystals.

Question

A Group I metal (lithium, sodium or potassium) is reacted with a Group VII element (chlorine, bromine or iodine). Which compound is formed when the Group I metal of highest density reacts with the Group VII element of lowest density? A lithium chloride B potassium chloride C potassium iodide D lithium iodide

Question

The properties of the element titanium, Ti, can be predicted from its position in the Periodic Table. Which row identifies the properties of titanium? can be used conducts electricity forms coloured has low density as a catalyst when solid compounds A B C D

Question

A balloon is filled with helium. Helium is a noble gas and makes the balloon rise up in the air. The density of air is 1.23 g / dm3. Which gas is helium? density in g / dm3 reaction with oxygen A 0.0899 burns rapidly B 0.179 does not react with oxygen C 1.78 does not react with oxygen D 3.75 does not react with oxygen

Question

Which property is shown by all metals? A They are extracted from their ores by heating with carbon. B They conduct electricity. C They form acidic oxides. D They react with hydrochloric acid to form hydrogen.

Question

Sodium nitrate is a white crystalline solid that decomposes on heating. sodium nitrate heat Which row describes the decomposition products formed when sodium nitrate is heated strongly? solid products gaseous products A sodium nitrite NO2 and O2 B sodium nitrite O2 only C sodium oxide NO2 and O2 D sodium oxide O2 only

Question

Molten iron from the blast furnace contains impurities. The process of turning the impure iron into steel involves blowing oxygen into the molten iron and adding calcium oxide. What are the reasons for blowing in oxygen and adding calcium oxide? blowing in oxygen adding calcium oxide A carbon is removed by reacting with oxygen reacts with acidic impurities making slag B carbon is removed by reacting with oxygen reacts with slag and so removes it C iron reacts with the oxygen reacts with acidic impurities making slag D iron reacts with the oxygen reacts with slag and so removes it

Question

Element Y reacts with copper(II) oxide to form copper. Element Y will not react with zinc oxide. Copper has no reaction with zinc oxide. What is the order of reactivity of these three elements, most reactive first? A Cu → Y → Zn B Cu → Zn → Y C Zn → Cu → Y D Zn → Y → Cu

Question

Which statement shows that a liquid is pure water? A It boils at 100 °C. B It has a pH value of 7. C It turns blue cobalt(II) chloride pink. D It turns white copper(II) sulfate blue.

Question

Which process removes carbon dioxide from the atmosphere? A combustion B decomposition C photosynthesis D respiration

Question

Ammonia is manufactured by the Haber process. N2(g) + 3H2(g) 2NH3(g) What are the conditions used in the Haber process? temperature pressure / °C / atm A 400 100 B 400 300 C 20 300 D 20 100

Question

Coating iron helps to prevent rusting. Which coating will continue to protect the iron even when the coating is damaged? A copper B paint C plastic D zinc

Question

A student suggests three uses of calcium carbonate (limestone). 1 manufacture of cement 2 manufacture of iron 3 treating alkaline soils Which suggestions are correct? A 1 and 2 only B 1 and 3 only C 2 and 3 only D 1, 2 and 3

Question

The Contact process is used to manufacture concentrated sulfuric acid and consists of four steps. Which step involves a catalyst? A production of sulfur dioxide gas B production of sulfur trioxide gas C production of oleum D production of concentrated sulfuric acid

Question

Which row about the production of ethanol by fermentation is correct? raw materials energy requirement rate of reaction A non-renewable high slow B renewable low slow C non-renewable low fast D renewable high fast

Question

Which statement about homologous series is correct? A Members of a homologous series have the same structural formula. B Members of a homologous series all have similar chemical properties. C Members of a homologous series all have similar physical properties. D Members of all homologous series are hydrocarbons.

Question

Increasing the number of atoms in one molecule of a hydrocarbon increases the amount of energy released when it burns. What is the correct order? less energy more energy released released A ethene ethane methane B ethene methane ethane C methane ethane ethene D methane ethene ethane

Question

Some properties of an organic compound J are listed. ● It is a liquid at room temperature. ● It is soluble in water. ● A solution of J reacts with calcium carbonate to form carbon dioxide. ● A solution of J has a pH of 3. In which homologous series does J belong? A alkane B alkene C alcohol D carboxylic acid

Question

Ethane, C2H6, reacts with chlorine in a substitution reaction. What are the products of this reaction? A chloroethane and hydrogen B chloroethane and hydrogen chloride C chloroethene and hydrogen D chloroethene and hydrogen chloride

Question

Which polymers or types of polymer are synthetic? 1 carbohydrates 2 nylon 3 proteins 4 Terylene A 1 and 3 B 1 and 4 C 2 and 3 D 2 and 4 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 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 16 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.).