Chemistry 0620/23 October/November 2020: question paper and mark scheme

Question

Which gas has the slowest rate of diffusion? A H2 B NH3 C CH4 D CO2

Question

When a dark grey solid element is heated, it changes directly into a purple gas. Which word describes this change? A boiling B evaporation C melting D sublimation

Question

Nickel(II) sulfate is a green solid that is soluble in water. Which method is used to obtain a pure sample of nickel(II) sulfate crystals from a mixture of nickel(II) sulfate and sand? A Heat the mixture with water and distil it to give nickel(II) sulfate. B Heat the mixture with water and leave it to crystallise. C Heat the mixture with water and filter off the nickel(II) sulfate. D Heat the mixture with water, filter and allow the solution to crystallise.

Question

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

Question

Molecules containing only non-metal atoms are covalently bonded. The formulae of four covalently bonded molecules are given below: 1 nitrogen, N2 2 carbon dioxide, CO2 3 ethene, C2H4 4 methanol, CH3OH Which of the molecules contain double bonds? A 1 and 4 B 2 and 3 C 2 and 4 D 4 only

Question

The arrangements of the electrons in two ions formed from elements X and Y are shown. X Y n = 20 n = 20 p = 19 p = 17 Which equation represents the reaction between elements X and Y? A X2 + 2Y → 2X+ + 2Y– B X2 + 2Y → 2X– + 2Y+ C 2X + Y2 → 2X+ + 2Y– D 2X + Y2 → 2X– + 2Y+

Question

Magnesium reacts with sulfuric acid. What are the formulae of the products formed in this reaction? A MgSO4 and H2 B MgSO4 and H2O C Mg(SO4)2 and H2 D Mg(SO4)2 and H2O

Question

Sodium reacts with chlorine to form sodium chloride. Which row describes the bonding in the three substances? sodium chlorine sodium chloride A covalent covalent covalent B covalent metallic ionic C metallic covalent ionic D metallic metallic covalent

Question

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–

Question

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 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

What is the empirical formula of an oxide of iron, formed by reacting 2.24 g of iron with 0.96 g of oxygen? A FeO B Fe2O C Fe2O3 D Fe3O4

Question

Electrolysis is carried out on dilute aqueous potassium bromide. Which products are formed at the anode and the cathode? anode cathode A bromine hydrogen B bromine potassium C hydrogen bromine D hydrogen potassium

Question

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

Question

Ethanol is used as a fuel. ethanol + oxygen → carbon dioxide + water Which statements are correct? 1 The reaction is endothermic. 2 The products have more energy than the reactants. 3 The oxygen for this reaction comes from the air. 4 The temperature of the reaction mixture rises during this reaction. A 1 and 2 B 1 and 3 C 2 and 4 D 3 and 4

Question

The reaction between hydrogen and oxygen releases 486 kJ / mol of energy. 2H2(g) + O2(g) → 2H2O(g) The bond energy of H–H is 436 kJ / mol and that of H–O is 464 kJ / mol. What is the bond energy of O=O? A 430 kJ / mol B 458 kJ / mol C 498 kJ / mol D 984 kJ / mol

Question

Which reaction of hydrochloric acid is a redox reaction? A 2Na + 2HCl → 2NaCl + H2 B Na2O + 2HCl → 2NaCl + H2O C NaOH + HCl → NaCl + H2O D Na2CO3 + 2HCl → 2NaCl + H2O + CO2

Question

Which reaction is an example of a photochemical reaction? A glucose forming carbon dioxide and water B magnesium reacting with oxygen C potassium reacting with water D silver chloride forming silver metal

Question

An excess of calcium carbonate is added to dilute hydrochloric acid, X. The carbon dioxide gas given off is collected and its volume recorded at regular time intervals. Line X on the graph shows the results obtained. The experiment is repeated using dilute hydrochloric acid, Y. Line Y on the graph shows the results obtained. 80 Y 60 X volume of gas / cm3 40 20 0 0 50 100 150 200 time / s Which statement about the two hydrochloric acid samples, X and Y, is correct? A They had the same volume but Y had higher concentration. B They had the same concentration but Y had a larger volume. C X had a higher concentration but Y had a larger volume. D Y had a higher concentration but X had a larger volume.

Question

Period 3 of the Periodic Table contains the elements sodium to argon. Element Q is a non-metal from this period. Which statement about Q is correct? A It conducts electricity. B It has a lower proton number than sodium. C It has electrons in only three shells. D It is malleable.

Question

Which metal has variable oxidation states? A aluminium B calcium C copper D sodium

Question

An aqueous cation reacts with aqueous sodium hydroxide to form a white precipitate. The precipitate is insoluble in excess sodium hydroxide. What is the aqueous cation? A aluminium ion B calcium ion C chromium ion D zinc ion

Question

Zinc oxide is an amphoteric oxide. Which row describes the reactions of zinc oxide? reaction reaction with alkalis with acids A B C D

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 statement about the halogens and their compounds is correct? A The colour of the element gets lighter going down Group VII. B The elements get less dense going down Group VII. C When chlorine is added to sodium iodide solution, iodine is formed. D When iodine is added to sodium bromide solution, bromine is formed.

Question

Elements in Group II of the Periodic Table show the same trends in their reaction with water and their density as Group I. Which row shows how the properties of barium compare with calcium? reaction density with water A faster higher B faster lower C slower higher D slower lower

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

An experiment is performed to determine the order of reactivity of metals X and Y compared to lead. Strips of each metal were added to separate test-tubes containing aqueous lead(II) nitrate, Pb(NO3)2. The results are shown. no change dark layer Pb(NO3)2(aq) metal X metal Y What is the order of reactivity, least reactive first? A Pb → X → Y B X → Y → Pb C X → Pb → Y D Y → Pb → X

Question

The equation for the reaction between iron(III) oxide and carbon monoxide is shown. Fe2O3 + xCO → yFe + zCO2 Which values of x, y and z balance the equation? x y z A 2 2 2 B 2 3 3 C 3 1 3 D 3 2 3

Question

Which process is used to separate oxygen from liquid air? A chromatography B distillation C filtration D fractional distillation

Question

What is the catalyst in the Haber process? A Fe B Ni C Pt D V2O5

Question

Ammonia is manufactured in an exothermic reaction. N2(g) + 3H2(g) 2NH3(g) What is the effect of lowering the pressure on the rate of formation of ammonia and percentage yield of ammonia at equilibrium? rate of formation percentage yield A decreases decreases B decreases increases C increases decreases D increases increases

Question

Part of the carbon cycle is shown. combustion Q R glucose CO2 plant CH4 P What are processes P, Q and R? P Q R A decomposition respiration photosynthesis B respiration photosynthesis decomposition C respiration decomposition photosynthesis D photosynthesis respiration decomposition

Question

Which row shows the conditions used for the manufacture of sulfuric acid in the Contact process? pressure / atm temperature / °C catalyst A 250 200 vanadium(V) oxide B 2 450 vanadium(V) oxide C 250 200 iron D 2 450 iron

Question

Which calcium compound does not neutralise an acid soil? A calcium oxide B calcium sulfate C calcium hydroxide D calcium carbonate

Question

Which product is obtained when bromine reacts with propene, CH3CH=CH2? A CH3CH=CHBr B CH3CBr=CHBr C CH3CH2CHBr2 D CH3CHBrCH2Br

Question

Propanol is oxidised by acidified potassium manganate(VII) in a similar way to ethanol. Which compound is produced by the oxidation of propanol with acidified potassium manganate(VII)? A CH3CH2OH B CH3CH2CH2OH C CH3COOH D CH3CH2COOH

Question

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

Which equation represents the formation of poly(propene) from propene? A B CH3 H CH3 H H H H H n C C C C n C C C C H H H H n H H H H n C D CH3 H CH3 H CH3 H H H H n C C C C n C C C C C H H H H n H H H H H n

Question

Which type of linkage joins the amino acids in a protein? A B C D O C O C C O C N O 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 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.).