Chemistry 0620/12 February/March 2021: question paper and mark scheme

Question

In which changes do the particles move further apart? W X gas liquid solid Y Z A W and X B W and Z C X and Y D Y and Z

Question

Gases are separated from liquid air by fractional distillation. The boiling points of four gases are shown. Which gas is both monoatomic and a liquid at –200 °C? boiling gas point / °C A argon –186 B helium –269 C neon –246 D nitrogen –196

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Impurities change the melting and boiling points of substances. Sodium chloride is added to a sample of pure water. How does the addition of sodium chloride affect the melting point and the boiling point of the water? melting point boiling point A increases increases B decreases decreases C increases decreases D decreases increases

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The apparatus used to separate a mixture of sand, methanol and ethanol is shown. S R P Q Which row identifies the labels on the diagrams? P Q R S A filtrate residue condenser fractionating column B filtrate residue fractionating column condenser C residue filtrate condenser fractionating column D residue filtrate fractionating column condenser

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A neutral atom, J, contains 45 neutrons and 35 electrons. Which row is correct for atom J? proton number nucleon number A 35 45 B 35 80 C 45 45 D 45 80

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Lithium and fluorine react to form lithium fluoride. A student writes three statements about the reaction. 1 Lithium atoms lose an electron when they react. 2 Each fluoride ion has one more electron than a fluorine atom. 3 Lithium fluoride is a mixture of elements. Which statements are correct? A 1 and 2 only B 1 and 3 only C 2 and 3 only D 1, 2 and 3

Question

Which definition of isotopes is correct? A atoms of the same element that have the same number of electrons and nucleons B atoms of the same element that have the same number of neutrons and protons C atoms of the same element that have the same number of protons but a different number of electrons D atoms of the same element that have the same number of protons but a different number of nucleons

Question

In which molecule are all the outer shell electrons from each atom used to form covalent bonds? A CH4 B Cl 2 C H2O D NH3

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What is the balanced chemical equation for the reaction between calcium and water? A Ca + H2O → CaOH + H2 B Ca + H2O → Ca(OH)2 + H2 C Ca + 2H2O → CaOH + H2 D Ca + 2H2O → Ca(OH)2 + H2

Question

A compound has the formula XF2 and has a relative mass of 70. What is element X? A gallium B germanium C sulfur D ytterbium

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The diagram shows a section of an overhead power cable. steel ceramic aluminium Which statement explains why a particular substance is used? A Aluminium has a low density and is a good conductor of electricity. B Ceramic is a good conductor of electricity. C Steel can rust in damp air. D Steel is more dense than aluminium.

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Three substances are electrolysed using inert electrodes. Which substances produce hydrogen at the negative electrode? 1 concentrated hydrochloric acid 2 concentrated aqueous sodium chloride 3 dilute sulfuric acid A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only

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Which row describes an endothermic reaction? energy level diagram energy transfer energy is transferred energy A from the surroundings to the reaction progress of reaction energy is transferred energy B from the surroundings to the reaction progress of reaction energy is transferred energy C from the reaction to the surroundings progress of reaction energy is transferred energy D from the reaction to the surroundings progress of reaction

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Fuels release heat energy when they burn. Which substances are used as fuels? 1 argon 2 butane 3 hydrogen 4 methane A 1 and 3 only B 1, 3 and 4 C 2, 3 and 4 D 2 and 4 only

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When zinc carbonate is mixed with dilute hydrochloric acid a change, M, takes place. When carbon is heated with copper(II) oxide a change, N, takes place. Which row describes changes M and N? M N A chemical chemical B chemical physical C physical chemical D physical physical

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The apparatus shown is used to measure the rate of a reaction. gas syringe reactants Which equation represents a reaction where the rate can be measured using this apparatus? A Mg(s) + 2HCl (aq) → MgCl 2(aq) + H2(g) B HCl (aq) + NaOH(aq) → NaCl (aq) + H2O(l) C Fe(s) + CuSO4(aq) → Cu(s) + FeSO4(aq) D 2Na(s) + Br2(l) → 2NaBr(s)

Question

P is a hydrated metal salt with a blue colour. When P is heated, water is given off, leaving solid Q. R is a hydrated metal salt with a pink colour. When R is heated, water is given off, leaving solid S. Which row gives the name of P and the colour of S? name of P colour of S A hydrated cobalt(II) chloride blue B hydrated cobalt(II) chloride white C hydrated copper(II) sulfate blue D hydrated copper(II) sulfate white

Question

Which property is shown by the alkali sodium hydroxide? A It has a pH less than pH 7. B It produces a gas when it is warmed with ammonium chloride. C It turns blue litmus red. D It turns universal indicator green.

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Part of the Periodic Table is shown. Which element forms an acidic oxide? A B C D

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When aqueous sodium hydroxide is added to a solution of a metal ion, a grey-green precipitate forms, which dissolves in excess to form a dark green solution. What is the identity of the metal ion? A chromium(III) B iron(II) C iron(III) D copper(II)

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Which statements describe the Periodic Table? 1 The elements are arranged in order of their nucleon number. 2 The elements are arranged in order of their proton number. 3 It is used to predict the properties of elements. A 1 and 3 B 1 only C 2 and 3 D 2 only

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Which row shows how the properties of the Group I elements change on descending the group? density melting point reactivity A decreases increases increases B decreases increases decreases C increases decreases increases D increases decreases decreases

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Copper is a transition element. Two compounds of copper are copper(II) oxide and copper(II) carbonate. Which row describes the two compounds? colour of copper(II) oxide copper(II) carbonate A acidic green B acidic white C basic green D basic white

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The metal beryllium does not react with cold water. It reacts with hydrochloric acid but cannot be extracted from its ore by using carbon. Where is beryllium placed in the reactivity series? magnesium A zinc B iron C copper D

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Pure iron is a soft metal. When mixed with small amounts of tungsten it produces a hard alloy called tungsten steel. Which statements are correct? 1 Pure iron is a transition element. 2 The particles in pure iron are arranged in ordered layers. 3 Tungsten steel is a compound. A 1, 2 and 3 B 1 and 2 only C 1 only D 2 and 3 only

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Which row describes magnesium? electrical reacts with conductivity dilute acid A low no B low yes C high no D high yes

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Four equations are shown. 1 C + O2 → CO2 2 CaCO3 → CaO + CO2 3 SiO2 + 2CO → Si + 2CO2 4 Fe2O3 + 3CO → 2Fe + 3CO2 Which equations represent reactions that take place during the extraction of iron from hematite? A 1, 2 and 3 B 1, 2 and 4 C 2, 3 and 4 D 3 and 4 only

Question

Copper is used to make saucepans. Which properties of copper make it suitable for this use? 1 Copper has a relatively high melting point. 2 Copper has a low density. 3 Copper is a good conductor of electricity. 4 Copper is a good conductor of heat. A 1 and 2 B 1 and 4 C 2 and 4 D 3 and 4

Question

Which pollutants are responsible for the erosion of buildings and statues? 1 carbon monoxide 2 oxides of nitrogen 3 sulfur dioxide A 1, 2 and 3 B 1 and 2 only C 2 and 3 only D 3 only

Question

Which combination of chemical compounds can be used to produce the fertiliser shown? N P K 21 : 16 : 8 SUPERGROW A (NH4)3PO4, KCl B NH4NO3, Ca3(PO4)2 C NH4NO3, CO(NH2)2 D NH4NO3, K2SO4, (NH4)2SO4

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X is produced when petrol burns completely in air. What is X? A argon B carbon dioxide C carbon monoxide D hydrogen

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Which substance is used as a bleach in the manufacture of paper? A carbon dioxide B nitrogen dioxide C silicon dioxide D sulfur dioxide

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What is an industrial use of calcium carbonate? A cracking of hydrocarbons B manufacture of aluminium C manufacture of cement D purification of water

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Which product is formed when calcium carbonate undergoes thermal decomposition? A calcium B calcium hydroxide C calcium oxide D calcium silicate

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The pie chart represents the composition of natural gas. Which sector represents methane? B C A D

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Which fraction, obtained from petroleum, is used for jet fuel? A bitumen B gasoline C kerosene D naphtha

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The formula of a hydrocarbon is CxHy. The equation for its complete combustion is shown. CxHy + 8O2 → 5CO2 + 6H2O What are the values of x and y? x y A 5 6 B 5 12 C 6 5 D 12 5

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Pentane is an alkane and pentene is an alkene. What is observed when bromine water is added to a sample of each compound? pentane pentene A becomes colourless becomes colourless B becomes colourless remains unchanged C remains unchanged becomes colourless D remains unchanged remains unchanged

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Molecule 1 undergoes a process to make molecule 2. process molecule 1 molecule 2 Which row describes the molecules and the process? molecule 1 process molecule 2 A monomer cracking polymer B monomer polymerisation polymer C small molecule polymerisation monomer D small molecule cracking monomer

Question

Which substance has long-chain molecules and is a constituent of food? A carbohydrate B nylon C poly(ethene) D Terylene 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.).