Chemistry 0620/23 October/November 2023: question paper and mark scheme

Question

A sample of a gas occupies 340 cm3 at room temperature and pressure. The temperature and pressure are both increased, but the volume occupied by the gas remains 340 cm3. Which row describes what happens to the particle speed and the average distance between the particles in the gas when the temperature and pressure are both increased? average distance particle speed between particles A unchanged unchanged B unchanged increased C increased unchanged D increased increased

Question

Which statements about the rate of diffusion of the gases ammonia, carbon monoxide, nitrogen and oxygen are correct? 1 Nitrogen and carbon monoxide will diffuse at the same rate. 2 Oxygen will diffuse slowest because it is an element, whereas the others are compounds. 3 Ammonia will diffuse fastest. A 1 and 2 B 1 and 3 C 1 only D 2 and 3

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

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Which statement explains why isotopes of an element have the same chemical reactions? A They have different numbers of neutrons. B They have ions with different numbers of electrons. C They have the same number of outer shell electrons. D They have the same number of protons.

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Magnesium reacts with oxygen to form magnesium oxide. What happens to magnesium atoms and oxygen atoms during this reaction? A Magnesium and oxygen share two electrons. B Magnesium gains two electrons and oxygen loses two electrons. C Magnesium loses one electron and oxygen gains one electron. D Magnesium loses two electrons and oxygen gains two electrons.

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Which row about the properties of both diamond and silicon(IV) oxide is correct? conductor type of of electricity molecule A yes giant covalent B yes simple covalent C no giant covalent D no simple covalent

Question

The equation represents the reaction between solid magnesium oxide and dilute hydrochloric acid to form magnesium chloride and water. MgO + 2HCl → MgCl 2 + H2O Which row shows the state symbols for hydrochloric acid, magnesium chloride and water? HCl MgCl 2 H2O A (aq) (aq) (l) B (aq) (l) (l) C (l) (aq) (aq) D (l) (l) (aq)

Question

Which substance is a mixture? A air B graphite C oxygen D water

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The number of moles of atoms X, Y and Z, in a compound, are shown. atom moles X 0.6 Y 1.2 Z 0.3 What is the formula of the compound? A XY2Z4 B XY4Z2 C X2YZ4 D X2Y4Z 10 1.0 mol of silver nitrate, AgNO3, contains 1.2 × 1024 ions. How many ions are there in 0.25 mol of iron(III) oxide, Fe2O3? A 1.5 × 1023 B 3.0 × 1023 C 7.5 × 1023 D 3.0 × 1024

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In the question paper above.

Question

Concentrated aqueous magnesium bromide is electrolysed using carbon electrodes. Which equations represent the reactions occurring at each electrode? positive electrode negative electrode A 2Br –(aq) → Br2(aq) + 2e– 2H+(aq) + 2e– → H2(g) B 2H+(aq) + 2e– → H2(g) 2O2–(aq) → O2(aq) + 4e– C Mg2+(aq) + 2e– → Mg(s) 2Br –(aq) → Br2(aq) + 2e– D 2O2–(aq) → O2(aq) + 4e– Mg2+(aq) + 2e– → Mg(s)

Question

Aqueous copper(II) sulfate is electrolysed using carbon electrodes. Which statement is correct? A Bubbles of hydrogen gas are formed at the anode. B Bubbles of oxygen gas are formed at the cathode. C Copper is deposited at the anode. D The blue colour of the solution fades.

Question

When water is added to anhydrous iron(III) chloride, FeCl 3, hydrated iron(III) chloride, FeCl 3•6H2O, is formed and energy is given out. FeCl 3 + 6H2O FeCl 3•6H2O Which reaction pathway diagram represents the formation of anhydrous iron(III) chloride in the reverse reaction? A B FeCl 3•6H2O FeCl 3 + 6H2O energy energy FeCl 3 + 6H2O FeCl 3•6H2O progress of reaction progress of reaction C D FeCl 3 + 6H2O FeCl 3•6H2O energy energy FeCl 3•6H2O FeCl 3 + 6H2O progress of reaction progress of reaction

Question

Ethene reacts with hydrogen. The equation is shown. C2H4 + H2 → C2H6 The bond energies are shown. bond energy bond in kJ / mol C–C +350 C=C +610 C–H +410 H–H +436 What is the energy change for the reaction? A –560 kJ / mol B –124 kJ / mol C +486 kJ / mol D +5496 kJ / mol

Question

Statements about four different acids are listed. ● A 0.0100 mol / dm3 solution of hydrochloric acid has a pH of 2. ● A 0.0100 mol / dm3 solution of ethanoic acid has a pH of 3.4. ● Hydrobromic acid, HBr, is a strong acid. ● Ethanoic acid is a slightly stronger acid than trimethylethanoic acid. What are the pH values of 0.0100 mol / dm3 HBr and 0.0100 mol / dm3 trimethylethanoic acid? pH of pH of 0.0100 mol / dm3 0.0100 mol / dm3 HBr trimethylethanoic acid A 2 3.3 B 2 3.5 C 3.4 3.3 D 3.4 3.5

Question

Anhydrous cobalt(II) chloride is blue and turns pink when water is added. How is this reaction reversed? A adding dilute acid B filtering C heating D cooling

Question

The reaction between hydrogen and nitrogen is reversible. The forward reaction is exothermic. N2(g) + 3H2(g) 2NH3(g) Which change to the conditions would increase the yield of ammonia? A add a catalyst B increase the pressure C increase the temperature D reduce the concentration of nitrogen

Question

Ethanol can be turned into ethanoic acid by passing it over hot copper(II) oxide. CH3CH2OH + 2CuO → CH3COOH + H2O + 2Cu What is this type of reaction? A precipitation B redox C thermal decomposition D neutralisation

Question

When heated strongly, silicon(IV) oxide reacts with carbon. SiO2 + 2C → Si + 2CO Which term describes what happens to silicon(IV) oxide? A thermal decomposition B neutralisation C oxidation D reduction

Question

Which statement about aqueous weak acids is correct? A Weak acids are always dilute aqueous solutions. B Weak acids dissociate fully in aqueous solution. C When a weak acid is added to blue litmus paper, it stays blue. D When a weak acid is added to solid magnesium, effervescence is seen.

Question

Which oxides are basic? 1 calcium oxide 2 sodium oxide 3 iron(II) oxide A 1, 2 and 3 B 1 and 2 only C 2 and 3 only D 3 only

Question

Zinc oxide is an amphoteric oxide. Zinc oxide is added to excess dilute hydrochloric acid. Zinc oxide is added to excess aqueous sodium hydroxide. Which row describes the observations made in these reactions? excess dilute excess aqueous hydrochloric acid sodium hydroxide A colourless solution forms colourless solution forms B colourless solution forms no visible change C fizzing colourless solution forms D fizzing no visible change

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Which row shows properties of an element that is in the same group of the Periodic Table as lithium? electrical density conductivity in g / cm3 A high 0.97 B high 8.93 C low 0.07 D low 3.12

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The elements in Group VII include chlorine, bromine and iodine. Which statements are correct? 1 Iodine is more dense than chlorine. 2 Iodine displaces chlorine from a solution containing chloride ions. 3 Bromine is a diatomic non-metal. 4 Chlorine gas is darker in colour than bromine vapour. A 1 and 2 B 1 and 3 C 2 and 4 D 3 and 4

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Cobalt is a transition element. What is a property of cobalt? A It can form coloured compounds. B It is a poor electrical conductor. C It has a low density. D It has a low melting point.

Question

Which metal has variable oxidation numbers? A aluminium B calcium C copper D sodium

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Which statement about alloys is correct? A Alloys are pure metal elements. B At least two or more metals react together to make alloys. C Alloys can be harder and stronger than a pure metal. D Steel is not an alloy because it can contain the non-metal carbon.

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A metal M is between sodium and magnesium in the reactivity series. Which reactions occur with M and its oxide? M can be extracted M reacts with steam by heating its oxide with carbon A no no B no yes C yes no D yes yes

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The diagrams show experiments to investigate rusting of iron nails. 1 2 3 layer of oil tap salt boiled water water water In which test-tubes do the nails rust? A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 1 only

Question

Which equation represents a reaction that takes place when iron is extracted from its ore in the blast furnace? A CaO + SiO2 → CaSiO3 B CaO + CO2 → CaCO3 C 2CO → C + CO2 D 2Fe + 3CO2 → Fe2CO3 + 3CO

Question

Some uses of water are listed. 1 for drinking 2 in chemical reactions 3 in swimming pools 4 in washing For which uses is it necessary to chlorinate the water? A 1 and 2 B 1 and 3 C 2 and 4 D 3 and 4

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

Which pair of compounds are structural isomers of each other? A CH3CH2CH3 and CH3CH2CH2CH3 B CH2=CHCH3 and CH3CH=CH2 C CH2(OH)CH2CH3 and CH3CH2CH2OH D CH3CH2CH2COOH and CH3COOCH2CH3

Question

Methane reacts with chlorine in sunlight. CH4 + Cl 2 → CH3Cl + HCl Which statements about this reaction are correct? 1 It is a substitution reaction. 2 It is an addition reaction. 3 It is a photochemical reaction. 4 It is catalysed by nickel. A 1 and 3 B 1 and 4 C 2 and 3 D 2 and 4

Question

Propene reacts with bromine to give one product only. What is the formula of the product? A CH3CH2CHBr2 B CH2BrCH2CH2Br C CH3CHBrCH2Br D CH3CH2CH2Br

Question

Ethanol can be manufactured by fermentation or by the catalytic addition of steam to ethene. Which statements describe an advantage of manufacturing ethanol by fermentation? 1 The yield of ethanol is low. 2 The method uses a batch process. 3 The process takes place at a lower temperature. 4 The ethanol is made from a renewable source. A 1 and 2 B 1 and 3 C 2 and 4 D 3 and 4

Question

A compound with the formula CH3COOC2H5 is formed from ethanol in two separate reactions. reaction 1 Ethanol reacts to form ethanoic acid. reaction 2 Ethanoic acid and ethanol react together to form CH3COOC2H5. Which row describes reaction 1 and reaction 2? reaction 1 reaction 2 A oxidation ester formation B oxidation addition C reduction ester formation D reduction addition

Question

The flow diagram shows how poly(ethene) may be made from petroleum. 1 2 3 petroleum fuel oil ethene poly(ethene) What are stages 1, 2 and 3? 1 2 3 A cracking polymerisation fractional distillation B cracking fractional distillation polymerisation C fractional distillation cracking polymerisation D fractional distillation polymerisation cracking

Question

Rf values are used to identify unknown substances using paper chromatography. Which statements about Rf values are correct? 1 Rf values are always less than 1.0. 2 Rf value = distance travelled by solvent ÷ distance travelled by unknown substance. 3 The higher the Rf value, the further the unknown substance travels. 4 Rf values are not affected by the solubility of the unknown substance. A 1 and 2 B 1 and 3 C 2 and 3 D 3 and 4

Question

The results of some tests on an aqueous solution of substance X are listed. 1 A cream precipitate is produced when adding aqueous silver nitrate. 2 Adding aqueous sodium hydroxide produces a green precipitate which dissolves in excess alkali. 3 Adding aqueous ammonia produces a green precipitate which is insoluble in excess ammonia. What is substance X? A chromium(III) bromide B chromium(III) chloride C iron(II) bromide D iron(II) chloride 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 89–103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 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.).