Chemistry 0620/23 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 is used to measure 13.7 cm3 of dilute hydrochloric acid? A balance B burette C conical flask D pipette

Question

Chromatography is carried out on a mixture of three substances. The chromatogram is sprayed with a locating agent. The result is shown. solvent front baseline What are possible reasons why the chromatogram shows only two spots? 1 One of the substances in the mixture is insoluble in the solvent. 2 The locating agent did not react with one of the substances in the mixture. 3 Two of the substances in the mixture have the same Rf values. 4 The Rf value of one of the substances is too small. A 1 and 2 B 1 and 4 C 2 and 3 D 3 and 4

Question

The structure of an atom of element X is shown. key 5p = electron 6n n = neutron p = proton What is element X? A boron B carbon C sodium D sulfur

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

Caesium is a metal in Group I of the Periodic Table. Which description of the bonding in caesium is correct? A electrostatic attraction between oppositely charged ions B electrostatic attraction between positive metal ions and mobile electrons C neighbouring metal atoms sharing pairs of electrons D strong attractive forces between atoms

Question

Why does magnesium oxide, MgO, have a very high melting point? A There is a very strong double bond between magnesium and oxygen. B There is a very strong attractive force between the magnesium oxide molecules. C The oxide ions are strongly attracted to positive ions. D The magnesium ions are strongly attracted to a sea of electrons.

Question

Aluminium metal reacts with iron(III) oxide to form aluminium oxide and iron. Which chemical equation for the reaction between aluminium and iron(III) oxide is correct? A FeO + Al → Al O + Fe B Fe2O + 2Al → Al 2O + 2Fe C Fe2O3 + Al → Al 2O3 + Fe D Fe2O3 + 2Al → Al 2O3 + 2Fe

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

Which row describes the reactions during the electrolysis of dilute aqueous sodium chloride? anode (+) reaction cathode (–) reaction A H2 → 2H+ + 2e– 2H2O + O2 + 4e– → 4OH– B 2H+ + 2e– → H2 4OH– → 2H2O + O2 + 4e– C 2H2O + O2 + 4e– → 4OH– H2 → 2H+ + 2e– D 4OH– → 2H2O + O2 + 4e– 2H+ + 2e– → H2

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

Ethene gas, C2H4, is completely burned in excess oxygen to form carbon dioxide and water. The equation for this exothermic reaction is shown. C2H4 + 3O2 → 2CO2 + 2H2O The table shows the bond energies involved in the reaction. bond energy bond (kJ / mol) C=C 614 C–H 413 O=O 495 C=O 799 O–H 467 What is the total energy change in this reaction? A –954 kJ / mol B –1010 kJ / mol C –1313 kJ / mol D –1369 kJ / mol

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

In which tube is a physical change taking place? A B C D water water dilute dilute hydrochloric hydrochloric acid acid iron nail magnesium calcium sodium carbonate chloride

Question

A chemical reaction occurs when the reacting particles collide. Which reaction conditions would produce the greatest rate of particle collisions? concentration reaction of acid temperature A decrease decrease B no change increase C increase increase D increase no change

Question

At room temperature, the conversion of nitrogen dioxide, NO2, into dinitrogen tetroxide, N2O4, is reversible. 2NO2(g) N2O4(g) brown colourless gas gas The forward reaction is exothermic. Which changes cause the equilibrium to shift to the left? pressure temperature A decrease decrease B decrease increase C increase decrease D increase increase

Question

The equation for the reaction between zinc and aqueous copper(II) sulfate is shown. Zn + CuSO4 → ZnSO4 + Cu Which statement is correct? A The oxidation state of the oxidising agent has changed from 0 to +2. B The oxidation state of the reducing agent has changed from 0 to +2. C The oxidation state of the reducing agent has changed from +2 to 0. D This is not a redox reaction. The solution changes from colourless to blue.

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

Which two compounds would react together to form the insoluble salt lead(II) chloride? compound solubility in water 1 lead(II) nitrate yes 2 lead(II) sulfate no 3 silver chloride no 4 sodium chloride yes A 1 and 3 B 1 and 4 C 2 and 3 D 2 and 4

Question

The elements in Group I include lithium, sodium and potassium. Which statements about these elements are correct? 1 Sodium is denser than lithium. 2 Lithium has a lower melting point than potassium. 3 Potassium is a relatively soft metal. 4 Sodium is less reactive than lithium but more reactive than potassium. A 1 and 2 B 1 and 3 C 2 and 4 D 3 and 4

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

Which statement about the noble gases is correct? A Argon is used in light bulbs and balloons. B Helium reacts with oxygen in the air. C They all have full outer electron shells. D They are all diatomic molecules.

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

A salt is heated strongly. The only products are a white solid and a colourless gas. What is the salt? A copper(II) carbonate B potassium carbonate C calcium nitrate D sodium nitrate

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

P, Q, R and S are four metals. P displaces Q from a solution of its sulfate. Q reacts with hydrochloric acid and can be extracted from its ore using carbon. R does not react with hydrochloric acid. The carbonate of S does not decompose when heated strongly. What is the order of reactivity of the metals, starting with the most reactive? most least reactive reactive A R P Q S B R Q P S C S P Q R D S Q P R

Question

Which substances can be used to detect the presence of water? 1 cobalt(II) chloride 2 copper(II) sulfate 3 litmus 4 methyl orange A 1 and 2 B 1 and 3 C 2 and 4 D 3 and 4

Question

Which processes increase the amount of carbon dioxide in the atmosphere? 1 burning ethanol 2 farming cattle 3 growing trees A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only

Question

Hydrogen and nitrogen react to form ammonia in the Haber process. N2 + 3H2 2NH3 The forward reaction is exothermic. Which statements about the process are correct? 1 Nitrogen is obtained from the air. 2 Increasing the temperature of the reaction increases the yield of ammonia. 3 Increasing the reaction pressure increases the yield of ammonia. 4 Vanadium(V) oxide is used as a catalyst. A 1 and 2 B 1 and 3 C 2 and 3 D 3 and 4

Question

The diagram shows the positions of sacrificial anodes on the steel hull of a yacht. anodes Which metal is used to make the anodes? A calcium B copper C sodium 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

Which reaction in the Contact process is catalysed by vanadium(V) oxide? A S(s) + O2(g) → SO2(g) B 2SO2(g) + O2(g) → 2SO3(g) C SO3(g) + H2SO4(l) → H2S2O7(l) D H2S2O7(l) + H2O(l) → 2H2SO4(l)

Question

Ethanol is produced by: 1 the catalytic addition of steam to ethene 2 fermentation. Which statement is correct? A Both processes require similar amounts of energy. B Both processes use a catalyst. C Process 1 uses a renewable resource. D Process 2 produces the purest ethanol.

Question

Which statement about a homologous series is correct? A All members have the same general formula. B All members have the same molecular formula. C All members have similar physical properties. D Members show a trend in their chemical properties.

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

A small quantity of a solid chemical is added to a large excess of aqueous ethanoic acid. No bubbles of gas are seen and the solid dissolves to give a colourless solution. What was the solid chemical? A calcium hydroxide B copper(II) oxide C magnesium D sodium carbonate

Question

Alkanes undergo substitution reactions with chlorine in the presence of ultraviolet light. Which equation shows a reaction of this type? A C3H6 + Cl 2 → C3H6Cl 2 B C3H8 + Cl 2 → C3H6Cl 2 + H2 C C3H8 + 2Cl 2 → C3H6Cl 2 + 2HCl D C3H6 + Cl 2 → C3H5Cl + HCl

Question

Which statement about carbohydrates and proteins is correct? A Carbohydrates and proteins are constituents of food. B Carbohydrates and proteins are natural polymers used to make larger molecules called monomers. C Carbohydrates and proteins are synthetic polymers. D Carbohydrates and proteins cause pollution as they are non-biodegradable. 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 89–103 104 105 106 107 108 109 110 111 112 114 116 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.).