Chemistry 0620/22 February/March 2021: question paper and mark scheme

Question

Which row about a change of state is correct? change of state energy change process A solid → liquid heat given out melting B gas → liquid heat taken in evaporation C solid → gas heat taken in sublimation D liquid → solid heat given out condensing

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

Question

Two different food colourings, X and Y, are tested using chromatography. Three pure dyes, 1, 2 and 3, are also tested. The chromatogram is shown. 10 9 solvent front 8 7 6 5 4 3 2 1 baseline 0 X Y dye dye dye 1 2 3 Which statements are correct? 1 X and Y both contain two or more dyes. 2 Dyes 2 and 3 are present in both X and Y. 3 The Rf of dye 1 is 0.625. A 1 and 2 only B 1 and 3 only C 1, 2 and 3 D 2 and 3 only

Question

Which statement about the atoms of all the isotopes of carbon is correct? A They are all radioactive. B They have the same mass. C They have the same number of neutrons. D They have the same number of electrons in the outer shell.

Question

Which diagram represents the structure of silicon(IV) oxide? A B C D

Question

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

How many electrons are used to form covalent bonds in a molecule of methanol, CH3OH? A 5 B 6 C 8 D 10

Question

Magnesium oxide has a high melting point. Carbon dioxide has a low melting point. Which row identifies the attractive forces that are broken when these compounds are melted? magnesium oxide carbon dioxide A strong attractions between molecules weak attractions between atoms B strong attractions between molecules weak attractions between molecules C strong attractions between ions weak attractions between atoms D strong attractions between ions weak attractions between molecules

Question

The ionic half-equation for the formation of oxygen during the electrolysis of aluminium oxide is shown. x O2– → O2 + y e– What are the values of x and y? x y A 1 2 B 1 4 C 2 2 D 2 4

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

Question

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.

Question

During the electrolysis of dilute sulfuric acid, hydrogen is collected at the cathode. What is the ionic half-equation for this reaction? A H+ + e – → H B H+ → H + e – C 2H+ + 2e– → H2 D 2H+ → H2 + 2e–

Question

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

Question

The equation for the complete combustion of methane is shown. CH4(g) + 2O2(g) → CO2(g) + 2H2O(g) The bond energies are shown in the table. bond energy bond in kJ / mol C–H +410 C=O +805 O–H +460 O=O +496 What is the energy change for the reaction? A –818 kJ / mol B –359 kJ / mol C –323 kJ / mol D +102 kJ / mol

Question

Hydrogen fuel cells can be used to power cars. Which statements about a fuel cell are correct? 1 The balanced equation for the reaction is H2 + O2 → H2O. 2 The fuel cell generates electricity. 3 In the fuel cell hydrogen is reduced. 4 The reactants are gases at room temperature. A 1 and 2 B 1 and 3 C 2 and 4 D 3 and 4

Question

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

Magnesium reacts with copper(II) oxide to give magnesium oxide and copper. Which substance is the oxidising agent in this reaction? A copper B copper(II) oxide C magnesium D magnesium oxide

Question

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

Question

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)

Question

Which statements about strong acids are correct? 1 They have a high concentration of OH– ions. 2 They have a pH value of 1. 3 They completely ionise in water. 4 They turn red litmus blue. A 1 and 3 B 1 and 4 C 2 and 3 D 2 and 4

Question

Metal X reacts with non-metal Y to form an ionic compound with the formula X2Y. Which statements are correct? 1 X is in Group I of the Periodic Table. 2 X is in Group II of the Periodic Table. 3 Y is in Group VI of the Periodic Table. 4 Y is in Group VII of the Periodic Table. A 1 and 3 B 1 and 4 C 2 and 3 D 2 and 4

Question

The table gives some properties of Group IV elements. density boiling point element g / cm3 / °C carbon 2.2 4827 silicon germanium 5.3 2830 tin 5.8 2270 lead 11.3 1755 Which row describes the properties of silicon? density boiling point g / cm3 / °C A 2.3 3 265 B 3.1 1 997 C 6.2 2 920 D 24.6 11 682

Question

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

Question

Why is cryolite used in the extraction of aluminium from bauxite? A as a catalyst for the process B as a solvent for aluminium oxide C it stops the carbon anodes burning away D it reduces aluminium ions in aluminium oxide

Question

Which statements about the uses of metals are correct? 1 Iron is used to make aircraft because iron has a low density. 2 Copper is used to make electric cables because copper is a good conductor of electricity. 3 Aluminium is used to make brass because aluminium is strong and hard. 4 Iron is mixed with additives to make an alloy used in chemical plant. A 1 and 2 B 3 and 4 C 1 and 3 D 2 and 4

Question

Which row describes the reactions of magnesium hydroxide and magnesium oxide? effect of heat on hydroxide effect of heating oxide with carbon A forms magnesium oxide magnesium and carbon dioxide formed B forms magnesium oxide no reaction C no reaction magnesium and carbon dioxide formed D no reaction no reaction

Question

The properties of an element are listed. Its melting point is 3414 °C. Some of its compounds are catalysts. It has variable oxidation states. Where is the element found in the Periodic Table? A alkali metals B halogens C noble gases D transition elements

Question

Petrol burns in a car engine to produce waste gases which leave through the car exhaust. One of these waste gases is an oxide of nitrogen. Which statement describes how this oxide of nitrogen is formed? A Carbon dioxide reacts with nitrogen in the catalytic converter. B Nitrogen reacts with oxygen in the car engine. C Nitrogen reacts with oxygen in the catalytic converter. D Petrol combines with nitrogen in the car engine.

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

Question

Which process does not produce carbon dioxide? A combustion of a hydrocarbon B photosynthesis C reaction between an acid and a metal carbonate D respiration

Question

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

Question

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

Question

Propane reacts with chlorine. Which row shows a condition required for this reaction and identifies the type of reaction? condition type of reaction A phosphoric acid catalyst addition B phosphoric acid catalyst substitution C ultraviolet light addition D ultraviolet light substitution

Question

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

Question

Which statement describes the reaction between ethene and steam? A a cracking reaction which produces ethane and hydrogen gas as products B an addition reaction which produces ethanol as the only product C an oxidation reaction which produces ethanoic acid as the only product D a slow reaction producing ethanol and carbon dioxide

Question

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

Question

The formula of an ester is CH3CH2CH2COOCH2CH2CH3. Which acid and alcohol react together to make the ester? acid alcohol A butanoic acid butanol B butanoic acid propanol C propanoic acid butanol D propanoic acid propanol

Question

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 structure represents a protein? H O H O A N C N C N C H O O O B C O O C C O O O O O O D C C N N C C H H 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 20 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.).