Chemistry 0620/12 October/November 2020: question paper and mark scheme

Question

‘The movement of a substance very slowly from an area of high concentration to an area of low concentration.’ Which process is being described? A a liquid being frozen B a solid melting C a substance diffusing through a liquid D a substance diffusing through the air

Question

Oxygen melts at –219 °C and boils at –183 °C. At which temperature is oxygen a liquid? A –225 °C B –189 °C C –175 °C D 25 °C

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Which diagram shows a burette? A B C D

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In the chromatography experiment shown, which label represents the solvent front? A B D C

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Different methods of separation rely on substances having different properties. Which property does distillation make use of? A boiling point B colour C particle size D solubility in different solvents

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Which statement about atomic structure is correct? A Isotopes have a different nucleon number but the same proton number. B Metal atoms gain electrons to achieve a noble gas electronic structure. C The nucleon number is the total number of electrons and neutrons in the nucleus of the atom. D Protons and neutrons are oppositely charged particles.

Question

Which element is a non-metal? A scandium B sodium C strontium D sulfur

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The structure of propane, C3H8, is shown. H H H H C C C H H H H How many electrons are involved in the bonding of propane? A 8 B 10 C 16 D 20

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Rubidium is in Group I of the Periodic Table and bromine is in Group VII. Rubidium reacts with bromine to form an ionic compound. Which row shows the electron change taking place for rubidium and the correct formula of the rubidium ion? electron change formula of ion formed A electron gained Rb+ B electron gained Rb– C electron lost Rb+ D electron lost Rb–

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Which statement explains why graphite is used as a lubricant? A All bonds between the atoms are weak. B It conducts electricity. C It has a low melting point. D Layers in the structure can slide over each other.

Question

The formula of which compound contains the largest number of Group VII atoms? A C13H13IO8 B Cl 2O6 C Al (BrO3)3 D NaFC2H2O2

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The relative atomic mass of chlorine is 35.5. When calculating relative atomic mass, which particle is the mass of a chlorine atom compared to? A a neutron B a proton C an atom of carbon-12 D an atom of hydrogen-1

Question

Universal indicator solution is added to a neutral solution of concentrated aqueous sodium chloride. The solution, which contains H+ (hydrogen), Na+ (sodium), Cl – (chloride) and OH– (hydroxide) ions, is electrolysed. The product at the cathode is hydrogen gas and the product at the anode is chlorine gas. What happens to the colour of the indicator in the solution during electrolysis? A The colour changes from blue to green. B The colour changes from blue to red. C The colour changes from green to blue. D The colour changes from green to red.

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Which energy level diagram represents an endothermic reaction? A B reactants products energy energy products reactants progress of reaction progress of reaction C D reactants reactants products energy energy products progress of reaction progress of reaction

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Which process is a physical change? A burning a piece of magnesium B dissolving calcium carbonate in hydrochloric acid C melting an ice cube D the rusting of an iron nail

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Which substance does not require oxygen in order to produce energy? A coal B hydrogen C natural gas 235 D U

Question

Nitrogen, N2, and hydrogen, H2, can be converted into ammonia, NH3, using a catalyst. What is the purpose of the catalyst? A to increase the amount of ammonia produced B to increase the rate of reaction C to reduce the amount of reactants needed D to reduce the rate of reaction

Question

A reaction is carried out at four different temperatures. The time taken for the reaction to complete at each temperature is measured. The results are shown. 70 60 50 40 time / s 30 20 10 0 0 10 20 30 40 50 60 temperature / °C What is the relationship between temperature and rate of reaction? A The rate decreases as the temperature increases. B The rate increases as the temperature increases. C The rate is proportional to the temperature. D The rate is inversely proportional to the temperature.

Question

During the manufacture of sulfuric acid, sulfur dioxide is converted to sulfur trioxide. 2SO2 + O2 → 2SO3 Which type of reaction is this? A displacement B neutralisation C oxidation D thermal decomposition

Question

When pink crystals of cobalt(II) chloride are heated, steam is given off and the colour of the solid changes to blue. CoCl 2•6H2O CoCl 2 + 6H2O What happens when water is added to the blue solid? colour temperature A changes to pink decreases B changes to pink increases C remains blue decreases D remains blue increases

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Which statement describes a base? A It reacts with ammonium chloride to produce ammonia gas. B It reacts with calcium carbonate to produce carbon dioxide gas. C It reacts with copper to produce hydrogen gas. D It turns blue litmus red.

Question

Which compound is an acidic oxide? A aluminium oxide B carbon dioxide C copper(II) oxide D magnesium oxide

Question

Which statement describes how a flame test is done? A The tip of a clean wire is dipped into the substance and the wire is placed in a blue Bunsen burner flame. B The tip of a clean wire is dipped into the substance and the wire is placed in a yellow Bunsen burner flame. C A wooden splint is lit and is placed above a test-tube containing the gas being tested. D A wooden splint is lit, blown out and the glowing splint put into a test-tube of the gas being tested.

Question

A student carries out an experiment to prepare pure magnesium sulfate crystals. The diagram shows the first stage of the preparation. stirrer magnesium carbonate dilute sulfuric acid He adds magnesium carbonate until no more reacts. Which process should he use for the next stage? A crystallisation B evaporation C filtration D neutralisation

Question

Which row about elements in the Periodic Table is correct? statement 1 statement 2 A two elements in the same group metals are on the have similar chemical properties left of the table B two elements in the same group metals are on the have similar chemical properties right of the table C two elements in the same period metals are on the have similar chemical properties left of the table D two elements in the same period metals are on the have similar chemical properties right of the table

Question

Tennessine, Ts, is a newly discovered element. The atomic number of tennessine is 117 and it is placed directly underneath astatine in Group VII of the Periodic Table. The trends in properties of Group VII elements are shown. boiling point density element colour reactivity / °C in g / cm3 fluorine –188 pale yellow 0.002 extremely high chlorine –35 green 0.003 very high bromine 60 red-brown 3.103 high iodine 184 dark grey 4.933 low Which statement about the properties of tennessine is likely to be correct? A Tennessine has a higher reactivity than astatine. B Tennessine has a lower boiling point than astatine. C Tennessine is a lighter colour than astatine. D Tennessine is more dense than astatine.

Question

A flammable gas needs to be removed from a tank at an industrial plant. For safety reasons, an inert gas is used. Which gas is suitable? A argon B hydrogen C methane D oxygen

Question

A substance, X, has the following properties. 1 It has a high melting point. 2 It conducts electricity in the solid and liquid states. 3 It is malleable. 4 It has a high density. What is X? A a ceramic B copper C graphite D sodium chloride

Question

Which diagram best represents the structure of a substance that is a good conductor of electricity at 25 °C? A B C D – + – + + – + – – + – +

Question

Some properties of element Y are listed. ● It reacts with hydrochloric acid to make hydrogen gas. ● It reacts with steam but not with cold water. ● The oxide of Y cannot be reduced by carbon. What is element Y? A copper B iron C magnesium D sodium

Question

Oxides of nitrogen are given out from car exhausts. Which row best shows why oxides of nitrogen are unwanted in the atmosphere? acidic toxic A no no B no yes C yes no D yes yes

Question

Water is purified using several processes. Four of the processes are listed. 1 Chlorine is added to water to kill any bacteria. 2 Water is passed through coarse gravel to remove large pieces of dirt. 3 Water is passed through wire screens to remove large twigs. 4 Water is passed through fine sand to remove small particles. In which order are the processes carried out? A 1→2→3→4 B 2→1→4→3 C 3→2→4→1 D 4→3→2→1

Question

When solid S is heated strongly, it forms gas G. G turns limewater cloudy. What are S and G and which type of reaction does S undergo? S G type of reaction A calcium carbonate carbon dioxide combustion B calcium carbonate carbon dioxide thermal decomposition C sodium carbonate oxygen combustion D sodium carbonate oxygen thermal decomposition

Question

The element sulfur is found in a number of different minerals. Which mineral contains the greatest percentage by mass of sulfur? A barite, BaSO4 B galena, PbS C gypsum, CaSO4 D pyrite, FeS2

Question

Which structure represents a molecule of ethanol? A B C D H H H H H H H O H C C H C C H C C O H H C C H H H H H H H O H

Question

Petroleum is separated into fractions by fractional distillation. Separation occurs in a fractionating column. Some properties of three of these fractions are shown. number of boiling point fraction carbon atoms in range / °C the molecules 1 5 –10 2 320–350 16–24 3 120–210 Which statement is correct? A Fraction 1 has a higher boiling point range than fraction 2. B Fraction 2 is removed from a higher point in the fractionating column than fraction 1. C Molecules in fraction 3 have shorter chains than those in fraction 2. D None of the fractions are liquid at room temperature.

Question

Which statement describes methane? A It is an alcohol. B It is an unsaturated molecule. C It contains carbon, hydrogen and oxygen atoms only. D Each molecule contains four single covalent bonds.

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The flow chart shows the preparation of ethanol and some important chemistry of ethanol. fermentation process Y substance X ethanol carbon dioxide + substance Z What are X, Y and Z? X Y Z A yeast combustion oxygen B glucose combustion steam C glucose polymerisation water D yeast fermentation glucose

Question

The structure of propane is shown. H H H H C C C H H H H Which statement about the atoms and the bonding in propane is correct? A All the bonds are single bonds. B Each carbon atom only bonds with two hydrogen atoms. C Propane is an unsaturated molecule. D There are three carbon-carbon bonds.

Question

The structure of a compound X is shown. O H C O H X is in the same homologous series as ethanoic acid. Which row describes some of the properties of an aqueous solution of X? reacts with CaCO3 neutralises turns methyl to produce a gas CuO orange red A no no no B no yes no C yes yes yes D yes no yes 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.).