Chemistry 0620/22 February/March 2023: question paper and mark scheme

Question

Substance M is a solid at 30 °C. The substance is heated to 80 °C and its temperature measured as it cools down to room temperature. The cooling curve is shown. 80 P temperature / qC 60 R 40 Q 20 S T 0 0 time Between which times is substance M freezing? A P to Q B Q to R C R to S D S to T

Question

Which gas has the fastest rate of diffusion? A Ar B C2H6 C HCl D H2S

Question

There are two stable isotopes of bromine. The mass number of isotope 1 is 79. The mass number of isotope 2 is 81. Which statement is correct? A The isotopes have the same number of neutrons. B The isotopes have different chemical properties. C The isotopes have different numbers of protons. D The isotopes have the same number of outer electrons.

Question

Which statement about ions and ionic bonds is correct? A Bromine atoms form negatively charged bromide ions. B Ionic bonds form between elements in Group VII of the Periodic Table. C Positive ions are formed when atoms lose protons. D Potassium iodide contains negatively charged potassium ions.

Question

Part of the Periodic Table is shown. F G Which type of chemical bonding is present in the oxide of F and in the oxide of G? oxide of F oxide of G A covalent covalent B covalent ionic C ionic covalent D ionic ionic

Question

Elements X and Y react to form a compound. Element X loses two electrons and element Y gains one electron. What is the charge on the ions of elements X and Y and what is the formula of the compound? formula of charge on X charge on Y compound A 2+ – X2Y B 2+ – XY2 C 2– + X2Y D 2– + XY2

Question

Which statement about graphite explains why it is used as an electrode? A It contains ions. B It has a giant covalent structure. C It is a metal. D It has mobile electrons.

Question

Methane, CH4, burns in air to form carbon dioxide and water. What is the balanced equation for this reaction? A CH4(g) + O2(g) → CO2(g) + 2H2O(g) B CH4(g) + 2O2(g) → CO2(g) + 2H2O(g) C CH4(g) + 2O2(g) → CO2(g) + H2O(g) D CH4(g) + 3O2(g) → CO2(g) + 2H2O(g)

Question

The equation for the thermal decomposition of sodium hydrogencarbonate is shown. 2NaHCO3 → Na2CO3 + H2O + CO2 The Mr of sodium hydrogencarbonate, NaHCO3, is 84. The Mr of sodium carbonate, Na2CO3, is 106. In an experiment, 2.1 g of sodium hydrogencarbonate is heated but not all of it decomposes. All of the carbon dioxide is collected and measured at room temperature and pressure. The total volume of carbon dioxide produced is 0.21 dm3. The volume of 1 mole of a gas at room temperature and pressure is 24 dm3. Which statement is correct? A The mass of sodium carbonate produced is 0.93 g. B The mass of sodium carbonate produced is 1.33 g. C The percentage yield of carbon dioxide is 10%. D The percentage yield of carbon dioxide is 35%.

Question

An electrolysis experiment is done using carbon electrodes. Hydrogen and oxygen are formed at the electrodes. What is the electrolyte? A aqueous copper(II) sulfate B concentrated hydrochloric acid C dilute aqueous sodium chloride D molten potassium oxide

Question

Concentrated aqueous copper(II) sulfate is electrolysed using copper electrodes. Which ionic half-equation describes the reaction taking place at the cathode? A 2H+ + 2e– → H2 B 4OH– → O2 + 2H2O + 4e– C Cu → Cu2+ + 2e– D Cu2+ + 2e– → Cu

Question

When powdered sodium carbonate and aqueous ethanoic acid are mixed, the temperature of the mixture falls. Which statement about this reaction is correct? A The reaction is endothermic and ∆H is negative. B The reaction is endothermic and ∆H is positive. C The reaction is exothermic and ΔH is negative. D The reaction is exothermic and ∆H is positive.

Question

Magnesium powder reacts with an excess of dilute hydrochloric acid to produce hydrogen gas. Which statements about this reaction are correct? 1 The smaller the particles of magnesium powder, the more slowly the hydrogen is produced. 2 The higher the temperature, the faster the magnesium powder disappears. 3 The lower the concentration of dilute hydrochloric acid, the faster the rate of reaction. 4 The faster the magnesium powder disappears, the faster the rate of reaction. A 1 and 2 B 2 and 3 C 2 and 4 D 3 and 4

Question

The reaction between two aqueous compounds, X and Y, is slow and exothermic. The graph shows how the rate of this reaction changes with time. rate 0 0 time A student suggests that the rate of reaction decreases with time because: 1 the activation energy decreases 2 the speed of the molecules of X and Y decreases 3 the concentration of both X and Y decreases with time. Which suggestions are correct? A 1 and 2 B 1 and 3 C 2 only D 3 only

Question

Hydrogen reacts with iodine to form hydrogen iodide. H2(g) + I2(g) → 2HI(g) Which statements explain why the reaction is faster when the pressure is increased, at constant temperature? 1 At higher pressure, the molecules are moving faster. 2 At higher pressure, more of the molecules have the required activation energy. 3 At higher pressure, the molecules are closer together. 4 At higher pressure, the molecules collide more frequently. A 1 and 2 B 1 and 3 C 2 and 4 D 3 and 4

Question

Ammonium sulfate is used as a fertiliser. It is made from ammonia and sulfuric acid. The ……1…… is made by the ……2…… process in which ……3…… is used as a catalyst. Which words complete gaps 1, 2 and 3? 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

The reversible reaction shown takes place in a closed system at constant temperature. P(g) + Q(g) + R(g) S(g) + T(g) When the reaction has reached equilibrium, more T is added. After the addition of T, which other substances increase in concentration? A P, Q, R and S B P and Q only C P, Q and R only D S only

Question

In which equation is the underlined substance acting as a reducing agent? A 3CO + Fe2O3 → 2Fe + 3CO2 B CO2 + C → 2CO C CuO + H2 → Cu + H2O D CaO + H2O → Ca(OH)2

Question

An aqueous solution reacts with a solid. The products are an alkaline gas, a salt and water. What are the aqueous solution and the solid? aqueous solution solid A sodium hydroxide magnesium carbonate B hydrochloric acid magnesium carbonate C hydrochloric acid ammonium chloride D sodium hydroxide ammonium chloride

Question

Butanoic acid partially dissociates in aqueous solution. Which row about butanoic acid is correct? effect on pH thymolphthalein A 3 turns blue B 5 turns colourless C 8 turns blue D 10 turns colourless

Question

Copper(II) sulfate is prepared by adding excess copper(II) carbonate to sulfuric acid. Why is an excess of copper(II) carbonate added? A to ensure all the copper(II) carbonate has reacted B to ensure all the sulfuric acid has reacted C to increase the rate of reaction D to increase the amount of copper(II) sulfate produced

Question

Part of the Periodic Table is shown. Which element has two electrons in its outer shell and three electron shells? A B C D

Question

Elements in Group I and Group II show the same trends in their reactions with water and in their density. 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

Which pair of compounds shows a transition element in two different oxidation states? A Cr2O3 and Cr2(SO4)3 B Cu2O and CuCO3 C ZnS and ZnSO4 D NiO and Ni(NO3)2

Question

Which description of brass is correct? A a compound of copper and zinc B a compound of copper and tin C a mixture of copper and zinc D a mixture of copper and tin

Question

What is the symbol of the metal used in the manufacture of aircraft because of its low density? A Al B Cu C Fe D Zn

Question

Which substances react to form hydrogen gas? 1 calcium and water 2 silver and dilute hydrochloric acid 3 magnesium and steam 4 zinc and dilute hydrochloric acid A 1, 3 and 4 B 1 and 3 only C 2 and 4 D 4 only

Question

Coke (carbon) and limestone are two raw materials used in the extraction of iron from hematite. Which type of reaction occurs when each substance is heated during the process? coke limestone A redox redox B redox thermal decomposition C thermal decomposition redox D thermal decomposition thermal decomposition

Question

Some combustion reactions produce pollutant gases. Which reactions produce a pollutant gas that is not present in clean air? 1 2CH4 + 3O2 → 2CO + 4H2O 2 2H2 + O2 → 2H2O 3 C + O2 → CO2 4 N2 + O2 → 2NO A 1 and 3 B 1 and 4 C 2 and 3 D 3 and 4

Question

One mole of alkane Y produces 72 dm3 of carbon dioxide when burned in excess oxygen, measured at room temperature and pressure. What is Y? A butane B ethane C methane D propane

Question

The structure of organic compound X is shown. H O H H C C O C H H H What is X? A ethyl ethanoate B ethyl methanoate C methyl ethanoate D methyl methanoate

Question

What is the structural formula of the compound formed in the addition reaction of propene with bromine? A CH3CHBrCH2Br B CH2BrCH2CH2Br C CHBr2CH2CH3 D CH3CBr2CH3

Question

Ethanol is produced industrially by fermentation and also by a catalysed addition reaction involving steam. Which row describes one advantage of each process? catalysed addition reaction fermentation involving steam A the reactant used is renewable it is a continuous process B the reactant used is renewable it requires little energy C it is a very rapid reaction it is a continuous process D it is a very rapid reaction it requires little energy

Question

Carboxylic acids react with alcohols when warmed with an acid catalyst. Which type of substance is formed in this reaction? A an alkene B an ester C a salt D a polymer

Question

Nylon is formed by condensation polymerisation. Which structure represents nylon? O O O O A C N C N C N C N H H H H O O O O B C N N C C N N C H H H H O O O O C C C N N C C N N H H H H O O O O D C C O N N O C C O N H H H

Question

Which structure represents the repeat unit of the addition polymer formed from but-1-ene? A B C D H C 2H 5 CH3 CH3 H H CH3 H H H H C C C C C C C C C C C H H H H H H H H H H H 37 2.00 g of powdered calcium carbonate is added to 50.0 cm3 of hydrochloric acid. Which apparatus is used to measure these quantities of calcium carbonate and hydrochloric acid? calcium carbonate hydrochloric acid A balance burette B balance thermometer C pipette burette D pipette thermometer

Question

In the question paper above.

Question

The diagram shows a chromatogram obtained from the colours of three different sweets, X, Y and Z. red red yellow yellow yellow red red sweet X sweet Y sweet Z How many different red dyes are present in the sweets? A 1 B 2 C 3 D 4

Question

A mixture contains sand and an aqueous solution of sodium chloride. Which processes are used to obtain a sample of solid sand and a sample of solid sodium chloride from the mixture? A crystallisation followed by filtration B evaporation followed by filtration C filtration followed by crystallisation D simple distillation followed by crystallisation

Question

A student tests an unknown compound M. The compound: ● produces a lilac flame using a flame test ● produces a gas which turns limewater cloudy when dilute hydrochloric acid is added. What is M? A sodium sulfate B sodium carbonate C potassium sulfate D potassium carbonate 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 89–103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 actinoids Fr Ra Rf Db Sg Bh Hs Mt Ds Rg Cn Nh Fl Mc Lv Ts Og francium radium rutherfordium dubnium seaborgium bohrium hassium meitnerium darmstadtium roentgenium copernicium nihonium flerovium moscovium livermorium tennessine oganesson – – – – – – – – – – – – – – – – – 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.).