Chemistry 0620/23 May/June 2023: question paper and mark scheme

Question

Nitrogen is heated in a balloon, which expands slightly. Which statements about the molecules of nitrogen are correct? 1 They move further apart. 2 They move more quickly. 3 They remain the same distance apart. 4 Their speed remains unchanged. A 1 and 2 B 1 and 4 C 2 and 3 D 3 and 4

Question

The diagrams represent some elements, compounds and mixtures. 1 2 3 4 Which row describes the numbered substances? 1 2 3 4 A element mixture of compounds compound mixture of elements B compound mixture of compounds element mixture of elements C element mixture of elements compound mixture of compounds D compound mixture of elements element mixture of compounds

Question

Two atoms, X and Y, have the same mass number but different atomic numbers. Which statement about X and Y is correct? A They have the same number of protons. B They have the same number of electrons. C They are in the same group of the Periodic Table. D They have different numbers of neutrons.

Question

A sample of pure iron contains three isotopes only. percentage abundance isotope of isotope / % n 2 Fe 54 6 Fe 56 92 Fe The iron in the sample has a relative atomic mass of 55.9. What is the value of n? A 53 B 55 C 57 D 58

Question

Magnesium oxide is a white solid at room temperature and pressure. Part of the structure of solid magnesium oxide is shown. key = Mg2+ magnesium ion = O2– oxide ion Three statements are listed. 1 Magnesium ions are smaller than oxide ions because they contain fewer electrons. 2 Magnesium oxide has good electrical conductivity when molten because the ions are mobile. 3 Magnesium oxide has a high melting point because of the strong electrostatic attraction between the ions and delocalised electrons in the giant lattice. Which statements are correct? A 1 and 2 B 1 and 3 C 2 and 3 D 2 only

Question

In which molecule are all the outer-shell electrons involved in covalent bonding? A Cl 2 B CH4 C HCl D NH3

Question

Which row describes the properties of silicon(IV) oxide? giant covalent melting point structure A no high B no low C yes high D yes low

Question

Which row describes the structure of a solid metal and explains the property? structure of solid metal property of solid metal A lattice of negative ions conducts electricity because in a sea of electrons the electrons are free to move B lattice of negative ions is malleable because the layers in a sea of electrons of ions can slide over each other C lattice of positive ions conducts electricity because in a sea of electrons the ions are free to move D lattice of positive ions is malleable because the layers in a sea of electrons of ions can slide over each other

Question

What is the formula of potassium oxide? A P2O B PO2 C KO D K2O

Question

A dilute aqueous solution of sodium bromide is electrolysed using inert electrodes. Which row identifies the product at the cathode and at the anode? cathode anode A bromine hydrogen B hydrogen bromine C hydrogen oxygen D oxygen hydrogen

Question

Aluminium is extracted by electrolysis, as shown. graphite anode steel case – + + – aluminium oxide dissolved in molten cryolite graphite cathode molten aluminium Which row shows the ionic half-equations at the cathode and the anode? cathode anode A Al 3+ → Al + 3e– 2O2– → O2 + 4e– B Al 3+ → Al + 3e– 2O2– + 4e– → O2 C Al 3+ + 3e– → Al 2O2– → O2 + 4e– D Al 3+ + 3e– → Al 2O2– + 4e– → O2

Question

The reaction pathway diagram for an exothermic reaction is shown. 3 1 energy 2 4 progress of reaction Which row identifies labels 1, 2, 3 and 4? 1 2 3 4 A reactants ΔH Ea products B products ΔH Ea reactants C reactants Ea ΔH products D products Ea ΔH reactants

Question

The equation for the complete combustion of ethene is shown. C2H4(g) + 3O2(g) → 2CO2(g) + 2H2O(g) Some bond energies are listed. bond energy bond in kJ / mol C–H 412 C–C 348 C=C 612 C–O 360 C=O 743 O–O 146 O=O 496 O–H 463 What is the overall energy change when one mole of ethene is completely burned? A –456 B –1076 C –1340 D –2126

Question

Magnesium reacts with hydrochloric acid to form magnesium chloride and hydrogen. Why does magnesium powder react faster than magnesium ribbon? A The magnesium atoms in the powder have a lower activation energy. B The powder has a smaller surface area. C The magnesium atoms in the powder have more frequent collisions with acid particles. D The magnesium atoms in the powder have greater kinetic energy.

Question

Which row shows the conditions used in the Contact process? pressure temperature catalyst / atm / °C A iron 2 100 B iron 200 450 C vanadium(V) oxide 2 450 D vanadium(V) oxide 200 100

Question

A student heats hydrated copper(II) sulfate. The blue crystals change to a white powder. How can the student reverse this reaction? A Add anhydrous copper(II) sulfate to the white powder. B Add water to the white powder. C Cool the white powder. D Reheat the white powder.

Question

Which reaction of hydrochloric acid is a redox reaction? A MgCO3 + 2HCl → MgCl 2 + H2O + CO2 B Mg(OH)2 + 2HCl → MgCl 2 + 2H2O C MgO + 2HCl → MgCl 2 + H2O D Mg + 2HCl → MgCl 2 + H2

Question

Which oxide is amphoteric? A Al 2O3 B CaO C Na2O D SO2

Question

Four statements about strong acids are listed. 1 They react with carbonates to form carbon dioxide. 2 They completely dissociate in aqueous solution. 3 They react with ammonium salts to form ammonia. 4 They are proton acceptors. Which statements are correct? A 1 and 2 B 1 and 3 C 2 and 4 D 3 and 4

Question

Which reaction mixture will produce a precipitate? A aqueous Na2CO3 and aqueous CuSO4 B dilute H2SO4 and aqueous NaOH C dilute HNO3 and solid MgO D solid CuO and dilute H2SO4

Question

Which set of elements shows the change from metallic to non-metallic character across a period of the Periodic Table? A beryllium → magnesium → calcium B fluorine → bromine → iodine C oxygen → boron → lithium D sodium → silicon → chlorine

Question

A sample of ethanoic acid and a sample of hydrochloric acid have the same concentration. How do the hydrogen ion concentration and pH of ethanoic acid compare to those of hydrochloric acid? ethanoic acid compared to hydrochloric acid hydrogen ion pH concentration A higher higher B higher lower C lower higher D lower lower

Question

What is a typical property of transition elements? A can act as catalysts B poor electrical conductivity C low melting point D low density

Question

Which statement about copper or aluminium is correct? A Aluminium is more dense than copper. B Aluminium is less reactive than copper. C Copper has high ductility. D Copper has poor electrical conductivity.

Question

Water from a reservoir flows to the water works where purification process 1 takes place followed by process 2. What are processes 1 and 2? process 1 process 2 A chlorination filtration B filtration chlorination C fractional distillation filtration D filtration fractional distillation

Question

Calcium reacts with cold water to produce hydrogen. Lead reacts slowly when heated in air to form an oxide but has almost no reaction with steam. Silver does not react with either air or water. Zinc reacts when heated with steam to produce hydrogen. What is the order of reactivity starting with the least reactive? least reactive most reactive A calcium lead zinc silver B calcium zinc lead silver C silver lead zinc calcium D silver zinc lead calcium

Question

Blocks of magnesium are attached to the bottom of a steel boat to prevent rusting. Which equation describes a change that prevents the steel from rusting? A Fe → Fe3+ + 3e– B Fe2O3 + 3Mg → 2Fe + 3MgO C 3Mg2+ + 2Fe → 2Fe3+ + 3Mg D Mg → Mg2+ + 2e–

Question

Which statements about the extraction of iron in a blast furnace are correct? 1 The temperature inside the blast furnace is increased by burning carbon. 2 Iron(III) oxide is reduced to iron by carbon monoxide. 3 The thermal decomposition of calcium carbonate forms slag. 4 Slag reacts with acidic impurities. A 1 and 2 B 1 and 4 C 2 and 3 D 3 and 4

Question

Which statements about water are correct? 1 Tap water has fewer impurities than distilled water. 2 Tap water will turn anhydrous cobalt(II) chloride pink. 3 The domestic water supply is treated with carbon to kill microbes. 4 Phosphates from fertilisers can cause deoxygenation of water. A 1 and 2 B 1 and 3 C 2 and 4 D 3 and 4

Question

Oxides of nitrogen form in car engines and are removed by catalytic converters. Which equation represents a reaction that occurs in a catalytic converter? A CO + NO2 → NO + CO2 B 2CO + 2NO → N2 + 2CO2 C CO2 + NO → NO2 + CO D CO2 + 2NO2 → N2 + 3O2 + C

Question

An alkene is represented by the formula CH3CH=CH2. Which name is given to this type of formula? A displayed B empirical C general D structural

Question

What is the structure of propanoic acid? A B H H O H H H O H C C C H C C C C H H OH H H H OH C D H H H H H H H H C C C OH H C C C C OH H H H H H H H

Question

Butane reacts with chlorine in the presence of ultraviolet radiation. What is the equation for this reaction? A C4H10 + Cl 2 → C4H8Cl 2 + H2 B C4H10 + Cl 2 → C4H9Cl + HCl C C4H10 + Cl 2 → 2C2H5Cl + H2 D C4H10 + Cl 2 → C2H4 + C2H5Cl + HCl

Question

A hydrocarbon P is cracked to make compound Q and hydrogen. Compound R is formed by the addition polymerisation of compound Q. To which homologous series do P, Q and R belong? alkene alkane A P only Q and R B Q only P and R C P and Q R only D P and R Q only

Question

Which substances are structural isomers? A but-2-ene and propene B ethyl ethanoate and butanoic acid C methyl methanoate and ethanol D propan-1-ol and butan-1-ol

Question

Ethanol is produced by: 1 the catalytic addition of steam to ethene 2 fermentation. Which statement is correct? A Both processes use similar amounts of energy. B Both processes use a catalyst. C Process 1 uses a temperature of 25–35 °C. D Process 2 uses a pressure of 60 atm.

Question

The two monomers shown can be used to form a condensation polymer. O H H H H O H H H H H H H H C C C C C C N C C C C C C N H O H H H H O H H H H H H H H H Which small molecule is released during this reaction? A H2O B NH3 C CO2 D CONH2

Question

Dilute hydrochloric acid is titrated into a conical flask containing sodium hydroxide solution and a few drops of methyl orange indicator. Which piece of apparatus is used to add the hydrochloric acid? A beaker B burette C measuring cylinder D pipette

Question

The chromatogram obtained from a chromatography experiment on substance S is shown. 4.5 cm solvent front 4.7 cm S 6.0 cm baseline 1.8 cm What is the Rf value of S? A 0.39 B 0.46 C 0.56 D 0.62

Question

Element X burns in air to form an acidic gas that decolourises potassium manganate(VII). What is X? A carbon B nitrogen C magnesium D sulfur 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 16 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.).