Chemistry 0620/23 October/November 2021: question paper and mark scheme

Question

Brownian motion and the diffusion of gases provide evidence for the particulate nature of matter. Which row identifies an example of Brownian motion and how molecular mass determines the rate of diffusion of gas molecules? Brownian motion diffusion A pollen grains in water are heavier gas molecules seen to move randomly diffuse more quickly B pollen grains in water are lighter gas molecules seen to move randomly diffuse more quickly C salt dissolves faster in heavier gas molecules hot water than in cold water diffuse more quickly D salt dissolves faster in lighter gas molecules hot water than in cold water diffuse more quickly

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

The nucleus of a particular atom consists of nineteen particles. Nine of them are positively charged and ten of them are uncharged. Which statement about this nucleus is correct? A The nucleus has a nucleon number of nine. B The nucleus has a nucleon number of ten. C The nucleus has a proton number of nine. D The nucleus has a proton number of ten.

Question

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

Question

A Group I element combines with a Group VII element and forms an ionic bond. Which row shows how the electronic structures change? Group I element Group VII element before after before after bonding bonding bonding bonding A 2,8,1 2,8,2 2,7 2,6 B 2,8 2,7 2,8 2,8,1 C 2,8,1 2,8 2,7 2,8 D 2,8 2,8,1 2,8 2,7

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 diagram shows the outer electron arrangement in a molecule of carbon dioxide? A B C D O C O O C O O C O O C O

Question

Aluminium oxide is an ionic compound containing Al 3+ ions and O2– ions. Aluminium hydroxide is an ionic compound containing Al 3+ ions and OH– ions. In which row are the formulae for aluminium oxide and aluminium hydroxide correct? aluminium aluminium oxide hydroxide A Al 2O3 Al (OH)3 B Al 3O2 Al OH3 C Al 2O3 Al OH3 D Al 3O2 Al (OH)3

Question

Effervescence is observed at the negative electrode (cathode) during the electrolysis of concentrated aqueous sodium chloride. Which element is produced at the negative electrode (cathode)? A chlorine B hydrogen C oxygen D sodium

Question

The energy level diagram for a chemical reaction is shown. products energy reactants progress of reaction Which statement about this reaction is correct? A The reaction is endothermic and energy is given out to the surroundings. B The reaction is endothermic and energy is taken in from the surroundings. C The reaction is exothermic and energy is given out to the surroundings. D The reaction is exothermic and energy is taken in from the surroundings.

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

What is the concentration of the solution when 31.8 g of sodium carbonate, Na2CO3, is dissolved in water to make a solution of 250 cm3? A 0.075 mol / dm3 B 0.30 mol / dm3 C 1.2 mol / dm3 D 1.5 mol / dm3

Question

A fuel cell is used to generate electricity. Which chemicals are used in a fuel cell? A hydrogen and methane B hydrogen and oxygen C nitrogen and methane D nitrogen and oxygen

Question

Sulfuric acid is manufactured using the Contact process. One of the reactions is shown. 2SO2(g) + O2(g) 2SO3(g) The forward reaction is exothermic. statement 1 The equation has more molecules on the left-hand side than on the right-hand side. statement 2 Using a higher pressure shifts the equilibrium to the left. statement 3 Higher temperatures increase the rate of reaction. statement 4 Increasing the temperature shifts the equilibrium to the right. Which alternative is correct? A Statement 1 is correct and explains statement 2. B Statement 1 and statement 3 are correct. C Statement 2 and statement 4 are correct. D Statement 3 is correct and explains statement 4.

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

Excess dilute hydrochloric acid is added to equal masses of powdered calcium carbonate in two separate experiments. Two different concentrations of hydrochloric acid are used. The temperature in both experiments is the same. The results show the change in mass of the reaction flask measured over time. mass of reaction 1.0 mol / dm3 HCl flask 2.0 mol / dm3 HCl 0 0 time Why is the rate of reaction for the 1.0 mol / dm3 hydrochloric acid slower? collision energy collision rate A lower higher B lower lower C same as for 2.0 mol / dm3 higher D same as for 2.0 mol / dm3 lower

Question

Basic oxides are neutralised by acidic oxides. Which element forms an oxide that neutralises calcium oxide? A hydrogen B magnesium C sodium D sulfur

Question

Four solid oxides are added to dilute hydrochloric acid and aqueous sodium hydroxide. Which row describes an amphoteric oxide? hydrochloric acid sodium hydroxide A key B = reacts C = does not react D

Question

Which row describes an acid and an oxidising agent? acid oxidising agent A proton acceptor electron acceptor B proton acceptor electron donor C proton donor electron acceptor D proton donor electron donor

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

Part of the Periodic Table is shown. J K L M N Which pairs of the elements J, K, L, M and N react together to form a product with a 1 : 1 ratio? A J and L K and M B J and M K and N C J and N K and L D J and N K and M

Question

Which property is shown by transition metals but not shown by Group I metals? A good electrical conductivity B good thermal conductivity C loss of electrons to form positive ions D variable oxidation states

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

Chromium is a more reactive metal than iron but less reactive than zinc. Which statements are correct? 1 Chromium does not react with dilute hydrochloric acid. 2 Chromium oxide is reduced when it is heated with carbon. 3 Chromium reacts with zinc oxide to form zinc. 4 Chromium reacts with steam to form hydrogen gas. A 1 and 2 B 1 and 3 C 2 and 4 D 3 and 4

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 statement describes how oxides of nitrogen are formed in a car engine? A Nitrogen from the air reacts with oxygen from petrol. B Nitrogen from the air reacts with oxygen from the air. C Nitrogen from petrol reacts with oxygen from petrol. D Nitrogen from petrol reacts with oxygen from the air.

Question

Ships are made of steel, an alloy of iron. Blocks of magnesium are attached to the underside of ships to prevent rusting. Which statement explains how the magnesium prevents rusting? A Magnesium oxidises instead of iron. B Magnesium stops air and water getting to the iron. C The magnesium forms an alloy with iron which does not corrode. D The magnesium reacts with rust as soon as it is formed.

Question

Which process is used to produce hydrogen for the Haber process? A electrolysis of water B reacting aluminium with sodium hydroxide C reacting iron with sulfuric acid D reacting methane with steam

Question

One of the steps in manufacturing sulfuric acid in the Contact process is shown. 2SO2(g) + O2(g) 2SO3(g) Which catalyst is used to increase the rate of this reaction? A aluminium oxide B iron C phosphoric acid D vanadium(V) oxide

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

What is the structure of propanol? A B H H O H O H C C C O H H C C O H H H H C D H H H H H H C C C O H H C C O H H H H H H

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

What is the main constituent of natural gas? A hydrogen B carbon monoxide C methane D nitrogen

Question

Which statement describes the members of a homologous series? A compounds with the same physical properties B compounds containing the same functional group C compounds containing the same number and type of bonds D compounds obtained from the same raw material

Question

The structures of two compounds are shown. H H O H H O H C C O C H C C C H H H H H O H Which statements about these compounds are correct? 1 They have the same molecular formula. 2 They have similar chemical properties. 3 They are structural isomers. A 1 only B 1 and 2 C 2 and 3 D 1 and 3

Question

Some reactions of substance Q are shown. add steam under pressure and a catalyst add bromine ethanol is made Q 1,2-dibromoethane is made add hydrogen and a catalyst P What is P? A ethane B ethanoic acid C ethene D poly(ethene)

Question

Proteins and starch are natural polymers. Which row identifies the method of polymerisation of proteins and starch? proteins starch A addition addition B condensation condensation C addition condensation D condensation addition

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.).