Chemistry 0620/21 May/June 2019: question paper and mark scheme

Question

Which statement explains why ammonia gas, NH3, diffuses at a faster rate than hydrogen chloride gas, HCl ? A Ammonia expands to occupy all of the space available. B Ammonia has a smaller relative molecular mass than hydrogen chloride. C Ammonia is an alkali and hydrogen chloride is an acid. D Ammonia molecules diffuse in all directions at the same time.

Question

2.00 g of powdered calcium carbonate is added to 50.0 cm3 of hydrochloric acid. Which apparatus is used to measure the calcium carbonate and the hydrochloric acid? calcium carbonate hydrochloric acid A balance burette B balance thermometer C pipette burette D pipette thermometer

Question

The measurements from a chromatography experiment using substance F are shown. The diagram is not drawn to scale. solvent front distance moved by F 100 mm 90 mm 55 mm 15 mm baseline What is the Rf value of F? A 0.55 B 0.61 C 0.90 D 1.64

Question

Which statement about an atom of fluorine, 199 F, is correct? A It contains more protons than neutrons. B It contains a total of 28 protons, neutrons and electrons. C Its isotopes contain different numbers of protons. D Its nucleus contains 9 neutrons.

Question

Which row describes the formation of single covalent bonds in methane? A atoms share a pair of electrons both atoms gain a noble gas electronic structure B atoms share a pair of electrons both atoms have the same number of electrons in their outer shell C electrons are transferred from one both atoms gain a atom to another noble gas electronic structure D electrons are transferred from one both atoms have the same number atom to another of electrons in their outer shell

Question

Which statement describes the structure of an ionic compound? A It is a giant lattice of oppositely charged ions. B It is a giant lattice of positive ions in a ‘sea’ of electrons. C It is a giant molecule of oppositely charged ions. D It is a simple molecule of oppositely charged ions.

Question

Propane burns in oxygen. C3H8 + xO2 → 3CO2 + yH2O Which values of x and y balance the equation? x y A 5 4 B 7 4 C 10 8 D 13 8

Question

A tablet contains 0.080 g of ascorbic acid (Mr = 176). What is the concentration of ascorbic acid when one tablet is dissolved in 200 cm3 of water? A 9.1 × 10–5 mol / dm3 B 4.5 × 10–4 mol / dm3 C 9.1 × 10–2 mol / dm3 D 2.3 × 10–3 mol / dm3

Question

Which statement about the electrolysis of copper(II) sulfate solution using carbon electrodes is correct? A A colourless gas is produced at the anode. B A colourless gas is produced at the cathode. C The colour of the electrolyte remains the same. D The mass of both electrodes remains constant.

Question

Aluminium metal is extracted from aluminium oxide by electrolysis. Which ionic half-equation describes a reaction that occurs at the named electrode? ionic half-equation electrode A 2O2– → O2 + 2e– anode B Al 3+ + 3e– → Al anode C 2O2– → O2 + 4e– cathode D Al 3+ + 3e– → Al cathode

Question

Which statement about the hydrogen fuel cell is not correct? A Chemical energy is converted into electrical energy. B Hydrogen is oxidised. C The reaction that takes place is endothermic. D Water is the only product.

Question

Nitrogen reacts with hydrogen to produce ammonia. N2 + 3H2 → 2NH3 The reaction is exothermic. The bond energies are shown in the table. bond energy bond in kJ / mol N≡N 945 H–H 436 N–H 390 What is the energy change for this reaction? A –1473 kJ / mol B –87 kJ / mol C 87 kJ / mol D 1473 kJ / mol

Question

Which change in reaction conditions increases both the collision rate and the proportion of molecules with sufficient energy to react? A addition of a catalyst B increasing the concentration of a reactant C increasing the surface area of a reactant D increasing the temperature of the reaction

Question

When blue-green crystals of nickel(II) sulfate are heated, water is produced and a yellow solid remains. When water is added to the yellow solid, the blue-green colour returns. Which process describes these changes? A combustion B corrosion C neutralisation D reversible reaction

Question

The graph shows how the yield of product in a reversible reaction changes as the temperature and pressure are changed. All reactants and products are gases. reactants products yield of product 300 °C 100 °C pressure Which row is correct for this reversible reaction? side of reaction forward with fewer moles reaction A reactant exothermic B reactant endothermic C product endothermic D product exothermic

Question

Which changes represent oxidation? 1 2I– → I2 + 2e– 2 Cr(VI) → Cr(III) 3 Fe(II) → Fe(III) A 1 and 2 B 1 and 3 C 1 only D 2 only

Question

Nitrogen(I) oxide, N2O, nitrogen(II) oxide, NO, and carbon monoxide, CO, are all non-metal oxides. They do not react with acids or bases. Which statement is correct? A They are acidic oxides. B They are amphoteric oxides. C They are basic oxides. D They are neutral oxides.

Question

The positions of elements W, X, Y and Z in the Periodic Table are shown. W Y X Z Which elements form basic oxides? A W, X and Y B W and X only C Y only D Z only

Question

Ethanoic acid is a weak acid. Hydrochloric acid is a strong acid. Which statements are correct? 1 Ethanoic acid molecules are partially dissociated into ions. 2 1.0 mol / dm3 ethanoic acid has a higher pH than 1.0 mol / dm3 hydrochloric acid. 3 Ethanoic acid is always more dilute than hydrochloric acid. 4 Ethanoic acid is a proton acceptor. A 1 and 2 B 1 and 3 C 2 and 4 D 3 and 4

Question

The properties of an element are shown. electrical conductivity density reaction with water high low reacts violently with cold water Which element has these properties? A B C D

Question

Which statement about elements in Group I and Group VII of the Periodic Table is correct? A Bromine reacts with potassium chloride to produce chlorine. B Iodine is a monatomic non-metal. C Lithium has a higher melting point than potassium. D Sodium is more reactive with water than potassium.

Question

Which statement about elements in Group VIII of the Periodic Table is correct? A They all have a full outer shell of electrons. B They all react with Group I elements to form ionic compounds. C They are all diatomic molecules. D They are all liquids at room temperature.

Question

The diagrams show the structure of two substances used to make electrical conductors. X Y Which statement correctly describes X and Y? A X is a pure metal and Y is a compound. B X is a pure metal and Y is an alloy. C X is a solid and Y is a liquid. D X is harder and stronger than Y.

Question

Three metal compounds, P, Q and R, are heated using a Bunsen burner. The results are shown. P colourless gas produced, which relights a glowing splint Q colourless gas produced, which turns limewater milky R no reaction Which row shows the identity of P, Q and R? P Q R A magnesium carbonate potassium carbonate potassium nitrate B magnesium carbonate potassium nitrate potassium carbonate C potassium nitrate magnesium carbonate potassium carbonate D potassium nitrate potassium carbonate magnesium carbonate

Question

Zinc is extracted from its ore, zinc blende, using two chemical reactions. 1 2ZnS + 3O2 → 2ZnO + 2SO2 2 2ZnO + C → 2Zn + CO2 Which substance is reduced in reactions 1 and 2? reaction 1 reaction 2 A O2 C B O2 ZnO C ZnS C D ZnS ZnO

Question

Four metals, zinc, M, copper and magnesium, are reacted with aqueous solutions of their nitrates. The results are shown. magnesium M copper zinc metal nitrate nitrate nitrate nitrate magnesium key zinc = reacts M = no reaction copper What is the order of reactivity of these four metals starting with the most reactive? A copper → zinc → M → magnesium B copper → M → zinc → magnesium C magnesium → M → zinc → copper D magnesium → zinc → M → copper

Question

Why is aluminium used to make containers for storing food? A It conducts electricity. B It has a high melting point. C It is resistant to corrosion. D It is strong.

Question

Water can be treated by filtration then chlorination. Which uses do not need water of this quality? 1 water for cooling in industry 2 water for washing clothes 3 water for drinking A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only

Question

Oxides of nitrogen are formed in car engines and are a source of air pollution. To decrease this pollution, catalytic converters are fitted to car exhausts. What happens to the oxides of nitrogen in the catalytic converter? A combustion B cracking C oxidation D reduction

Question

The diagram shows an experiment to investigate how paint affects the rusting of iron. P Q iron painted iron air water What happens to the water level in tubes P and Q? tube P tube Q A falls rises B no change rises C rises falls D rises no change

Question

Ammonia is manufactured by the Haber Process. N2(g) + 3H2(g) 2NH3(g) The forward reaction is exothermic. Which conditions maximise the yield of ammonia? pressure temperature A high high B high low C low high D low low

Question

The carbon cycle is shown. atmospheric carbon dioxide X respiration decomposition Y Z green plants dead organic matter death and excretion animals Which row describes processes X, Y and Z? X Y Z A respiration combustion photosynthesis B respiration photosynthesis combustion C photosynthesis combustion respiration D photosynthesis respiration combustion

Question

Which row shows the conditions used in the Contact process? temperature pressure catalyst / °C / atm A 25 2 iron B 25 200 iron C 450 2 vanadium(V) oxide D 450 200 vanadium(V) oxide

Question

The diagram represents a lime kiln used to heat limestone to a very high temperature. waste gases lime kiln limestone fuel in fuel in air in air in X What leaves the kiln at X? A calcium carbonate B calcium hydroxide C calcium oxide D calcium sulfate

Question

Which fuel could be gasoline? Is it obtained from petroleum? yes no Is it used as Is it used as fuel for cars? fuel for cars? yes no yes no A B C D

Question

Why is ethanol a member of the homologous series of alcohols but propane is not? A Ethanol has two carbon atoms per molecule but propane has three. B Ethanol can be made from ethene but propane is obtained from petroleum. C Ethanol is a liquid but propane is a gas. D Ethanol contains the same functional group as other alcohols but propane does not.

Question

Chlorine reacts with methane. Which statements are correct? 1 The reaction takes place in the dark. 2 The reaction of chlorine with methane forms chloromethane. 3 Chloromethane reacts with chlorine to produce dichloromethane. 4 The reaction of chlorine with methane is an addition reaction. A 1 and 2 B 1 and 3 C 2 and 3 D 3 and 4

Question

Which statements about aqueous ethanoic acid are correct? 1 Ethanoic acid contains the functional group –COOH. 2 Ethanoic acid reacts with carbonates to produce hydrogen. 3 Ethanoic acid turns Universal Indicator paper blue. 4 Ethanoic acid has a pH lower than pH 7. A 1 and 2 B 1 and 3 C 1 and 4 D 2 and 4

Question

The structure of an ester is shown. O CH3 C OCH2CH2CH3 What is the name of the ester? A ethyl propanoate B methyl propanoate C propyl ethanoate D propyl methanoate

Question

The structure of a polymer is shown. O O O O Which type of polymer is shown and by which process is it formed? type of polymer formed by A carbohydrate addition polymerisation B carbohydrate condensation polymerisation C polyester addition polymerisation D polyester condensation polymerisation 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.).