Chemistry 0620/21 October/November 2019: question paper and mark scheme

Question

Samples of four gases are released in a room at the same time. The gases are carbon dioxide, CO2, hydrogen chloride, HCl, hydrogen sulfide, H2S, and nitrogen dioxide, NO2. Which gas diffuses fastest? A carbon dioxide B hydrogen chloride C hydrogen sulfide D nitrogen dioxide

Question

A student is asked to measure the time taken for 0.4 g of magnesium carbonate to react completely with 25.0 cm3 of dilute hydrochloric acid. Which pieces of apparatus does the student need? A balance, stop-clock, pipette B balance, stop-clock, thermometer C balance, pipette, thermometer D stop-clock, pipette, thermometer

Question

Four different food colourings are analysed using chromatography. The results are shown on the chromatogram. The diagram is not drawn to scale. Which food colouring contains a component with an Rf value of 0.3? solvent front 10 cm 8 cm 6 cm 4 cm 2 cm baseline A B C D

Question

Which statement about an ionic compound is not correct? A It conducts electricity when dissolved in water. B It has a high melting point due to strong attractive forces between ions. C It has a regular lattice of oppositely charged ions in a ‘sea of electrons’. D The ionic bonds are formed between metallic and non-metallic elements. 52

Question

An isotope of chromium is represented by 24 Cr . Which statement about an atom of this isotope of chromium is correct? A It contains 24 electrons. B It contains 24 neutrons. C It contains 28 protons. D It contains 52 neutrons.

Question

Element X has two isotopes, 126 X and 146 X . Which statement about these isotopes is correct? A They have different chemical properties because they have different numbers of neutrons. B They have the same chemical properties because they have the same number of outer shell electrons. C They have the same nucleon number because the sum of the number of protons and electrons is the same. D They have different positions in the Periodic Table because they have different numbers of neutrons.

Question

How are the structures of diamond and silicon(IV) oxide similar? A Molecules of both diamond and silicon(IV) oxide are held together by weak attractive forces. B They both contain atoms arranged in planes held together by weak bonds. C They both contain ions that are free to move. D The carbon in diamond and the silicon in silicon(IV) oxide each have four covalent bonds.

Question

Which statement describes the structure of copper? A It has a lattice of negative ions in a ‘sea of electrons’. B It has a lattice of negative ions in a ‘sea of protons’. C It has a lattice of positive ions in a ‘sea of electrons’. D It has a lattice of positive ions in a ‘sea of protons’.

Question

Four fertilisers are each supplied in 100 kg bags. Which fertiliser supplies the greatest mass of nitrogen per 100 kg bag? A ammonium nitrate, NH4NO3 B ammonium phosphate, (NH4)3PO4 C ammonium sulfate, (NH4)2SO4 D urea, CO(NH2)2

Question

Calcium carbonate reacts with dilute hydrochloric acid. The equation for the reaction is shown. CaCO3 + 2HCl → CaCl 2 + H2O + CO2 1.00 g of calcium carbonate is added to 50.0 cm3 of 0.0500 mol / dm3 hydrochloric acid. Which volume of carbon dioxide is made in this reaction? A 30 cm3 B 60 cm3 C 120 cm3 D 240 cm3

Question

Which rows correctly show cathode and anode products from the electrolysis of the named electrolyte? electrolyte cathode product anode product 1 copper(II) sulfate solution copper oxygen using copper electrodes 2 molten lead(II) bromide lead bromine 3 dilute sodium bromide solution hydrogen oxygen 4 copper(II) sulfate solution hydrogen oxygen using carbon electrodes A 1 and 2 only B 1 and 4 only C 2 and 3 only D 3 and 4 only

Question

What are the ionic half-equations for the electrode reactions during the electrolysis of concentrated aqueous sodium chloride? anode cathode A Cl 2 + 2e– → 2Cl – H2 → 2H+ + 2e– B 2Cl – → Cl 2 + 2e– 2H+ + 2e– → H2 C H2 → 2H+ + 2e– Cl 2 + 2e– → 2Cl – D 2H+ + 2e– → H2 2Cl – → Cl 2 + 2e–

Question

Which statements about endothermic reactions are correct? 1 The energy of the products is greater than the energy of the reactants. 2 The energy of the reactants is greater than the energy of the products. 3 The temperature of the surroundings increases during the reaction. 4 The temperature of the surroundings decreases during the reaction. A 1 and 3 only B 1 and 4 only C 2 and 3 only D 2 and 4 only

Question

Which gases are used to generate electricity in a fuel cell? A carbon dioxide and oxygen B hydrogen and methane C hydrogen and oxygen D methane and carbon dioxide

Question

Which is a chemical change? A boiling water B cooking an egg C dissolving sugar D melting ice cubes

Question

The rate of reaction between magnesium and dilute hydrochloric acid is increased by increasing the concentration of the acid. How does this affect the reacting particles? proportion of particles with collision rate of particles sufficient energy to react A increases increases B increases stays the same C stays the same increases D stays the same stays the same

Question

Dinitrogen tetroxide, N2O4, is converted into nitrogen dioxide, NO2, in a reversible reaction. N2O4(g) 2NO2(g) The forward reaction is endothermic. Which conditions give the highest equilibrium yield of nitrogen dioxide? pressure temperature / atmospheres A 2 high B 2 low C 50 high D 50 low

Question

The equation for the reaction between iron(II) sulfate and bromine is shown. 6FeSO4 + 3Br2 → 2Fe2(SO4)3 + 2FeBr3 Which row identifies the oxidising agent and the reducing agent? oxidising agent reducing agent A Br2 FeSO4 B FeSO4 Br2 C FeBr3 Fe2(SO4)3 D Fe2(SO4)3 FeBr3

Question

Which statement about amphoteric oxides is correct? A They are made by combining an acidic oxide with a basic oxide. B They react with water to give a solution of pH 7. C They react with both acids and bases. D They do not react with acids or bases.

Question

Carbonic acid is a weak acid formed when carbon dioxide dissolves in water. What is the pH of the solution? A 1 B 5 C 7 D 9

Question

A method used to make copper(II) sulfate crystals is shown. 1 Place dilute sulfuric acid in a beaker. 2 Warm the acid. 3 Add copper(II) oxide until it is in excess. 4 Filter the mixture. 5 Evaporate the filtrate until crystals start to form. 6 Leave the filtrate to cool. What are the purposes of step 3 and step 4? step 3 step 4 A to ensure all of the acid has reacted to obtain solid copper(II) sulfate B to ensure all of the acid has reacted to remove the excess of copper(II) oxide C to speed up the reaction to obtain solid copper(II) sulfate D to speed up the reaction to remove the excess of copper(II) oxide

Question

Lead(II) sulfate is an insoluble salt. Which process is not used to prepare a pure sample of this salt? A crystallisation B drying C filtration D precipitation

Question

Part of the Periodic Table is shown. Which element is used to provide an inert atmosphere? A B C D

Question

Which pair of elements reacts together most violently? A chlorine and lithium B chlorine and potassium C iodine and lithium D iodine and potassium

Question

Which pair of compounds shows that transition elements have variable oxidation states? A Cr2O3 and CrBr3 B CuSO4 and CuCl 2 C Fe2O3 and FeCl 2 D NiO and NiCl 2

Question

Some properties of substance X are listed. ● It conducts electricity when molten. ● It has a high melting point. ● It burns in oxygen and the oxide dissolves in water to give a solution with pH 11. What is X? A a covalent compound B a macromolecule C a metal D an ionic compound

Question

Which statement is correct? A Aluminium is used in the manufacture of aircraft because it has a high density. B Copper is used for cooking utensils because it is a good conductor of heat. C Mild steel is used for car bodies because it is resistant to corrosion. D Stainless steel is used for cutlery because it is a conductor of electricity.

Question

Iron rusts but aluminium does not easily corrode. Which statement explains why aluminium does not easily corrode? A It is an alloy. B It is below iron in the reactivity series. C It is not a transition element. D Its surface is protected by an oxide layer.

Question

Which statement about the extraction of aluminium is correct? A Aluminium is formed at the cathode during the electrolysis of aluminium oxide. B Hematite is mainly aluminium oxide. C Molten cryolite is used to raise the melting point of the aluminium oxide. D Oxygen gains electrons at the anode during the electrolysis of aluminium oxide.

Question

River water contains soluble impurities, insoluble impurities and bacteria. River water is made safe to drink by filtration and chlorination. Which statement is correct? A Filtration removes bacteria and insoluble impurities, and chlorination removes soluble impurities. B Filtration removes insoluble impurities, and chlorination kills the bacteria. C Filtration removes soluble and insoluble impurities, and chlorination kills the bacteria. D Filtration removes soluble impurities and bacteria, and chlorination removes insoluble impurities.

Question

Which physical property is used to separate the nitrogen and oxygen from air? A boiling point B density C electrical conductivity D molecular mass

Question

The apparatus shown is set up and left for a week. damp iron wool air water Which diagram shows the level of the water at the end of the week? A B C D

Question

Which statement about the carbon cycle is correct? A Carbon is absorbed from the atmosphere by combustion and released into it by respiration. B Carbon is absorbed from the atmosphere by photosynthesis and released into it by combustion. C Carbon is absorbed from the atmosphere by both respiration and combustion. D Carbon is released into the atmosphere by both photosynthesis and respiration.

Question

Ammonium sulfate is used as a fertiliser. It is made from ammonia and sulfuric acid. Which words complete gaps 1, 2 and 3? The ……1…… is made by the ……2…… process in which ……3…… is used as a catalyst. 1 2 3 A ammonia Contact iron B ammonia Haber vanadium(V) oxide C sulfuric acid Contact vanadium(V) oxide D sulfuric acid Haber iron

Question

Which process is used to obtain lime from limestone? A cracking B fractional distillation C neutralisation D thermal decomposition

Question

Petroleum is separated by fractional distillation. Which statement about the fractions produced is correct? A Bottled gas for heating and cooking is obtained from the naphtha fraction. B Diesel oil is used as a fuel for jet aircraft. C Substances used to make polishes are obtained from the lubricating fraction. D The kerosene fraction contains many useful waxes.

Question

Which products are obtained by the cracking of an alkane? alkene hydrogen water A B C D

Question

Ethanol is manufactured by the catalytic addition of steam to ethene and by fermentation. Which statement describes an advantage of fermentation compared to the catalytic addition of steam to ethene? A Fermentation is a more rapid reaction. B Fermentation produces a purer product. C Fermentation uses a higher temperature. D Fermentation uses renewable resources.

Question

The diagram shows the structure of a monomer and of the polymer made from it. H H H H n C C C C H H H H n What are the monomer and polymer? monomer polymer A ethane poly(ethane) B ethane poly(ethene) C ethene poly(ethane) D ethene poly(ethene)

Question

Which polymers possess the same linkage? A nylon and protein B protein and starch C starch and nylon D nylon and 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 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.).