Chemistry 0620/21 October/November 2021: question paper and mark scheme

Question

Decane has a freezing point of –30 °C and a boiling point of 174 °C. A small sample of decane is placed in an open beaker in an oven at a temperature of 120 °C and at atmospheric pressure for 24 hours. What happens to the sample of decane? A It boils. B It evaporates. C It melts. D It sublimes.

Question

A student put exactly 25.00 cm3 of dilute hydrochloric acid into a conical flask. The student added 2.5 g of solid sodium carbonate and measured the change in temperature of the mixture. Which apparatus does the student need to use? A balance, measuring cylinder, thermometer B balance, pipette, stopwatch C balance, pipette, thermometer D burette, pipette, thermometer

Question

A student separates sugar from pieces of broken glass by dissolving the sugar in water and filtering off the broken glass. filtrate What is the filtrate? A broken glass only B broken glass and sugar solution C pure water D sugar solution

Question

Which statement explains why metals conduct electricity when solid? A They have atoms which are free to move. B They have electrons which are free to move. C They have molecules which are free to move. D They have positive ions which are free to move.

Question

Which description of brass is correct? A alloy B compound C element D non-metal

Question

The equation for the reaction of iron(III) oxide with carbon monoxide is shown. Fe2O3(s) + 3CO(g) → 2Fe(s) + 3CO2(g) What is the maximum mass of iron that can be made from 480 g of iron(III) oxide? A 56 g B 112 g C 168 g D 336 g

Question

Which statement describes the attractive forces between molecules? A They are strong covalent bonds which hold molecules together. B They are strong ionic bonds which hold molecules together. C They are weak forces formed between covalently-bonded molecules. D They are weak forces which hold ions together in a lattice.

Question

Which statement about carbon is correct? A Diamond and graphite both have simple molecular structures. B Diamond and graphite are both used to make cutting tools. C Each carbon atom in diamond is bonded to three other carbon atoms. D Graphite conducts electricity and has a giant covalent structure.

Question

The formula of an aluminium ion is Al 3+. What is the formula of aluminium sulfate? A Al 2SO4 B Al (SO4)2 C Al 2(SO4)3 D Al 3(SO4)2

Question

Which statements about the products of electrolysis, using inert electrodes, are correct? 1 When molten lead(II) bromide is electrolysed, bromine is formed at the cathode. 2 When dilute sulfuric acid is electrolysed, oxygen is formed at the anode. 3 When concentrated aqueous sodium chloride is electrolysed, sodium is formed at the cathode. 4 When concentrated hydrochloric acid is electrolysed, chlorine is formed at the anode. A 1 and 2 B 1 and 3 C 2 and 4 D 3 and 4

Question

Chlorine reacts with ethane to produce chloroethane and hydrogen chloride. H H H H H C C H + Cl Cl H C C Cl + H Cl H H H H The reaction is exothermic. The bond energies are shown in the table. bond energy bond in kJ / mol C–Cl +340 C–C +350 C–H +410 Cl –Cl +240 H–Cl +430 What is the energy change for the reaction? A –1420 kJ / mol B –120 kJ / mol C +120 kJ / mol D +1420 kJ / mol

Question

Hydrogen is used as a fuel in rockets and is also used in hydrogen fuel cells. Which statements are correct? 1 Both uses produce water vapour. 2 Burning hydrogen produces polluting gases. 3 A fuel cell produces electricity. A 1, 2 and 3 B 1 and 3 only C 1 only D 2 and 3 only

Question

Which statements about the effect of increasing the temperature on the rate of a reaction are correct? 1 It increases the rate of a reaction. 2 It increases the activation energy. 3 It increases the frequency of collisions. A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only

Question

Ammonia is made by reacting nitrogen with hydrogen. The equation for the reaction is shown. N2(g) + 3H2(g) 2NH3(g) The forward reaction is exothermic. Which changes in temperature and pressure decrease the yield of ammonia? temperature pressure A decrease decrease B decrease increase C increase decrease D increase increase

Question

X is a pink solid. Y is a blue solid. When X is heated, water is produced and the solid turns blue. When water is added to Y, the solid turns pink. What are X and Y? X Y A anhydrous cobalt(II) chloride hydrated cobalt(II) chloride B hydrated cobalt(II) chloride anhydrous cobalt(II) chloride C anhydrous copper(II) sulfate hydrated copper(II) sulfate D hydrated copper(II) sulfate anhydrous copper(II) sulfate

Question

Iron(II) chloride solution reacts with chlorine gas. The equation is shown. 2FeCl 2(aq) + Cl 2(g) → 2FeCl 3(aq) Which statements about this reaction are correct? 1 Fe2+ ions are reduced to Fe3+ ions. 2 Chlorine acts as a reducing agent. 3 Fe2+ ions each lose an electron. 4 Cl 2 molecules are reduced to Cl – ions. A 1 and 2 B 2 and 3 C 2 and 4 D 3 and 4

Question

Which row describes the properties of an acid? property 1 property 2 A proton acceptor pH less than 7 B proton acceptor pH more than 7 C proton donor pH less than 7 D proton donor pH more than 7

Question

Which element forms an amphoteric oxide? A aluminium B carbon C magnesium D silicon

Question

Copper(II) chloride crystals are made by adding solid copper(II) carbonate to dilute hydrochloric acid until no more dissolves. Which process is used to obtain pure copper(II) chloride crystals from the mixture? A distillation of the mixture B evaporation of the mixture C filtration followed by drying of the residue D filtration followed by evaporation of the filtrate

Question

Moving from right to left across the Periodic Table the elements show increasing metallic character. Why does metallic character increase from right to left across a period? A The atoms have more electrons in their outer shells. B The atoms more readily gain electrons to form negative ions. C The atoms more readily lose electrons to form positive ions. D The charge on the nucleus of each atom gets larger.

Question

A period of the Periodic Table is shown. group I II III IV V VI VII VIII element R S T V W X Y Z The letters are not their chemical symbols. Which statement is correct? A Element R does not conduct electricity. B Elements R and Y react together to form an ionic compound. C Element Z exists as a diatomic molecule. D Element Z reacts with element T.

Question

Group VII elements show trends in their physical properties going down the group. element X Y Z chlorine –101 –34 0.003 bromine –7 59 3.1 iodine 114 184 4.9 Which row shows the missing headings for the properties in the table? X Y Z A density in g / cm3 boiling point in °C melting point in °C B melting point in °C boiling point in °C density in g / cm3 C boiling point in °C density in g / cm3 melting point in °C D boiling point in °C melting point in °C density in g / cm3

Question

Some properties of two metals, G and H, are shown. metal G metal H the formula of the chloride is GCl high melting point reacts with cold water has more than one oxidation state Which row about metals G and H is correct? metal G metal H A in Group I of the Periodic Table in Group II of the Periodic Table B in Group I of the Periodic Table transition metal C in Group II of the Periodic Table in Group I of the Periodic Table D in Group II of the Periodic Table transition metal

Question

The noble gases are in Group VIII of the Periodic Table. Which statement explains why noble gases are unreactive? A They all have eight electrons in their outer shells. B They all have full outer shells. C They are all gases. D They are all monoatomic.

Question

Which statement is correct for all metals? A They conduct electricity when molten. B They gain electrons when they form ions. C They have a low density. D They have a low melting point.

Question

Which statement about the extraction of metals is correct? A Aluminium is extracted from the ore bauxite by electrolysis. B Aluminium is extracted from the ore hematite by electrolysis. C Iron is extracted from the ore bauxite by electrolysis. D Iron is extracted from the ore hematite by electrolysis.

Question

Aluminium objects do not need protection from corrosion. Iron objects must be protected from corrosion. Which statement explains why aluminium resists corrosion? A Aluminium does not form ions easily. B Aluminium does not react with water or air. C Aluminium has a protective oxide layer. D Aluminium is below iron in the reactivity series.

Question

Which statements about the thermal decomposition of copper(II) nitrate are correct? 1 A brown gas is given off. 2 A gas which relights a glowing splint is given off. 3 The solid residue is an acidic oxide. A 1 only B 1 and 2 C 1 and 3 D 2 and 3

Question

Covering iron with zinc prevents the iron from rusting even when the zinc is scratched. Covering iron with tin prevents the iron from rusting, but when the tin is scratched the iron underneath starts to rust. Which statement is correct? A Both tin and zinc prevent iron from rusting by sacrificial protection. B Both tin and zinc prevent iron from rusting by stopping water and carbon dioxide reaching the iron. C Tin is more reactive than iron and prevents iron from rusting until it is scratched. D Zinc loses electrons more easily than iron and prevents iron from rusting by corroding first.

Question

Which statements about the Haber process are correct? 1 One of the raw materials is extracted from liquid air by fractional distillation. 2 One of the raw materials is produced by the reaction of steam and methane. 3 The catalyst for the Haber process is vanadium(V) oxide. A 1 only B 1 and 2 only C 2 and 3 only D 1, 2 and 3

Question

Which raw material is used in the Contact process? A air B ammonia C carbon D nitrogen

Question

Lime (calcium oxide) is used to treat waste water from a factory. Which substance is removed by the lime? A ammonia B sodium chloride C sodium hydroxide D sulfuric acid

Question

An alkane molecule of molecular formula C8H18 undergoes cracking. The equation for the reaction is shown. C8H18 → Q + 2R Substance R has two carbon atoms per molecule and decolourises aqueous bromine. What is substance Q? A butane B butene C ethane D ethene

Question

Fuel X produces carbon dioxide and water when it is burned in air. So does fuel Y. What could X and Y be? X Y A C H2 B C C8H18 C CH4 H2 D CH4 C8H18

Question

Which molecule contains only single covalent bonds? A propane B propanoic acid C propene D propyl propanoate

Question

Alkanes react with chlorine to form chloroalkanes. Which statement about the reactions of alkanes with chlorine is correct? A Alkanes react with chlorine by addition. B The gaseous product turns red litmus blue. C The chlorine atom in chloroethane is covalently bonded. D The general formula of the chloroalkanes is CnH2nCl.

Question

Part of the structure of a very large molecule is shown. H OH H H H OH H H C C C C C C C C H H H OH H H H OH Which term describes the small unit used to make this molecule? A hydrocarbon B monomer C polymer D saturated

Question

Propene reacts with steam to form propanol. C3H6(g) + H2O(g) → C3H7OH(g) Which type of reaction takes place? A addition B condensation C oxidation D substitution

Question

Which statement about aqueous ethanoic acid is correct? A It reacts with magnesium to produce a salt and hydrogen. B It reacts with sodium hydroxide to produce a salt and hydrogen. C It reacts with ammonium salts to produce ammonia. D It turns red litmus blue.

Question

The diagram shows the partial structure of Terylene. O O O C O O C C O From which pair of compounds is it made? O O A HO C C OH + HO OH O O B HO C OH + HO C OH O O C HO OH + HO C C OH O O O O D HO C C OH + HO C C OH 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.).