Chemistry 0620/22 February/March 2025: question paper and mark scheme

Question

The diagrams show containers of gas at the same temperature. All containers have the same size. Which container contains gas at the highest pressure? A B C D

Question

A cooling curve for a substance is shown. U W temperature V Y X Z time Which statement is correct? A Between U and V, the substance is condensing. B Between V and W, heat is being absorbed from the surroundings. C Between W and X, the particles are close together and randomly arranged. D Between Y and Z, the substance is changing from a liquid to a solid.

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

Sulfur atoms can form the negative ion S2–. Three other atoms or ions are listed. ● argon, Ar ● calcium, Ca ● oxide, O2– How many of these atoms or ions have the same electronic configuration as S2–? A 0 B 1 C 2 D 3

Question

Element T has two isotopes, 126 T and 146 T. 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

Lithium is in Group I of the Periodic Table. Nitrogen is in Group V of the Periodic Table. Lithium reacts with nitrogen to form the ionic compound lithium nitride, Li3N. What happens to the electrons when lithium atoms and nitrogen atoms form ions? lithium nitrogen A each lithium atom loses one each nitrogen atom gains three electron to form an Li+ ion electrons to form an N3– ion B each lithium atom loses one each nitrogen atom gains five electron to form an Li+ ion electrons to form an N5– ion C each lithium atom gains one each nitrogen atom loses three electron to form an Li– ion electrons to form an N3+ ion D each lithium atom gains one each nitrogen atom loses five electron to form an Li– ion electrons to form an N5+ ion

Question

For which covalent compound does the dot-and-cross diagram correctly show the outer shell electrons? A B C D H Cl H Cl H N H H N H H H

Question

Which row identifies the positive and the negative particles present in a giant metallic lattice? positive particles negative particles A anions cations B anions delocalised electrons C cations anions D cations delocalised electrons

Question

Which formula for the named compound is correct? A calcium oxide, CaO B cobalt(II) chloride, Co2Cl C sulfur dioxide, S2O2 D anhydrous copper(II) sulfate, Cu(SO4)2

Question

The equation for the reaction of magnesium with dilute sulfuric acid is shown. Mg + H2SO4 → MgSO4 + H2 [Mr: MgSO4, 120] Which mass of magnesium sulfate is formed when 12 g of magnesium completely reacts with dilute sulfuric acid? A 5g B 10 g C 60 g D 120 g

Question

An organic compound, Q, contains carbon, hydrogen and oxygen only. Q contains 40.0% carbon and 6.7% hydrogen by mass. What is the empirical formula of Q? A CHO B CH2O C C2HO2 D C3H6O3

Question

The value of the Avogadro constant is 6.02 × 1023. What is the total number of atoms in 2.00 mol of ammonia gas? A 1.20 × 1024 B 2.41 × 1024 C 4.82 × 1024 D 2.89 × 1025

Question

Three aqueous solutions, L, M and N, are electrolysed using inert electrodes. L is concentrated hydrochloric acid. M is concentrated aqueous sodium chloride. N is dilute aqueous sodium chloride. Which solutions produce a pale yellow-green gas at the anode? A L and M B L only C M and N D N only

Question

Dilute sulfuric acid is electrolysed using inert electrodes. What are the ionic half-equations for the reactions that take place at each electrode? positive electrode negative electrode A 2H+ + 2e– → H2 4OH– → 2H2O + O2 + 4e– B 2H+ + 2e– → H2 4OH– + 4H+ → 4H2O C 4OH– → 2H2O + O2 + 4e– 2H+ + 2e– → H2 D 4OH– + 4H+ → 4H2O 2H+ + 2e– → H2

Question

Which statements about hydrogen–oxygen fuel cells are correct? 1 They convert chemical energy into electrical energy. 2 Hydrogen is reduced in the fuel cells. 3 They do not produce any atmospheric pollutants. A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only

Question

The reaction pathway diagram for the reaction between P and Q to form R and S is shown. Which letter represents the enthalpy change for the reaction? D R + S B energy C P + Q A progress of reaction

Question

The equation for the complete combustion of methane is shown. CH4(g) + 2O2(g) → CO2(g) + 2H2O(g) The table shows some bond energies. bond energy bond in kJ / mol C–H 410 C=O 805 O=O 496 O–H 460 What is the enthalpy change for this reaction? A –1458 kJ / mol B –818 kJ / mol C –359 kJ / mol D +102 kJ / mol

Question

Which change is a physical change? A cracking an alkane B evaporating ethanol C fermenting glucose D neutralising an acid

Question

Which statements explain why increasing the temperature in a reaction involving gases increases the rate of reaction? 1 It increases the collision frequency between the gas particles. 2 It lowers the activation energy. 3 It increases the kinetic energy of the gas particles. 4 It increases the number of gas particles per unit volume. A 1 and 3 B 1 and 4 C 2 and 3 D 2 and 4

Question

The equation for the reaction between ammonia and oxygen is shown. 4NH3(g) + 5O2(g) 4NO(g) + 6H2O(g) ΔH = –909 kJ / mol Which two changes to the reaction conditions will both move the position of equilibrium to the right? change 1 change 2 A increasing the temperature decreasing the pressure B increasing the temperature increasing the pressure C decreasing the temperature increasing the pressure D decreasing the temperature decreasing the pressure

Question

Mercury(II) oxide, HgO, decomposes when heated. The equation is shown. 2HgO → 2Hg + O2 Why is this a reduction reaction? A The products weigh less than the reactants. B There are fewer reactants than products. C There is a gain of oxygen. D There is a loss of oxygen.

Question

Some information about two dilute acids is shown. acid concentration dilute acid pH in mol / dm3 nitric acid 0.1 1.0 propanoic acid 0.4 2.6 Three statements about the acids are listed. 1 Nitric acid has a lower pH because it dissociates more than propanoic acid. 2 Propanoic acid has a lower concentration of hydrogen ions than nitric acid. 3 Propanoic acid has a higher pH because it has a higher concentration. Which statements are correct? A 1 and 2 B 1 and 3 C 2 only D 3 only

Question

Element E is a metal in Group I of the Periodic Table and element G is a non-metal in Group VII. Both of these elements form oxides. Which statement about their oxides is correct? A Both oxides are acidic. B Both oxides are basic. C The oxide of E is acidic and the oxide of G is basic. D The oxide of G is acidic and the oxide of E is basic.

Question

Lead(II) sulfate is an insoluble salt. Which method is suitable for obtaining pure solid lead( II) sulfate? A Mix aqueous lead(II) nitrate and aqueous potassium sulfate, heat to evaporate all of the water, collect the solid and then wash and dry it. B Mix aqueous lead(II) nitrate and aqueous potassium sulfate, filter, collect the filtrate, crystallise, then wash and dry the crystals. C Mix aqueous lead(II) nitrate and dilute sulfuric acid, filter, then wash and dry the residue. D Titrate aqueous lead(II) hydroxide with dilute sulfuric acid, crystallise, then wash and dry the crystals.

Question

The elements oxygen and sulfur are in the same group of the Periodic Table. Which statement about oxygen and sulfur is not correct? A They are non-metals. B They have giant covalent structures. C They have six electrons in the outer electron shells of their atoms. D They react together to form an acidic oxide.

Question

Tennessine, Ts, is at the bottom of Group VII of the Periodic Table. What are the predicted properties of tennessine at room temperature? A a black solid, more dense than iodine B a black solid, more reactive than iodine C a colourless gas, less dense than chlorine D a colourless gas, less reactive than chlorine

Question

An example of sacrificial protection is the fitting of zinc blocks to the outside of a ship’s steel hull. Which statement explains why zinc is used to protect the iron in the steel from rusting? A Zinc is more reactive than iron so it loses electrons more easily. B Zinc is less reactive than iron so it loses electrons more easily. C Zinc is more reactive than iron so it gains electrons more easily. D Zinc is less reactive than iron so it gains electrons more easily.

Question

Which statement about alloys is correct? A Alloys are harder than pure metals because they contain strong intermolecular forces. B Brass is an alloy containing mainly copper and tin. C The different-sized atoms in an alloy mean that the layers cannot easily slide over each other. D There are no alloys containing carbon because carbon is a non-metal.

Question

Separate pieces of aluminium foil and copper foil are heated in air. The copper foil reacts to give a black solid. The aluminium foil does not react. Which statement explains these observations? A Aluminium has an unreactive layer, but copper does not. B Aluminium is below copper in the reactivity series. C Copper reacts with moisture in the air, but aluminium does not. D Copper reacts with nitrogen in the air, but aluminium does not.

Question

Which row gives the symbol equation for the formation of carbon monoxide and for the reduction of iron(III) oxide in a blast furnace? equation for the formation equation for the reduction of carbon monoxide of iron(III) oxide A 2C + O2 → 2CO FeO + CO → Fe + CO2 B CO2 + C → 2CO FeO + CO → Fe + CO2 C C + O2 → CO2 Fe2O3 + 3CO → 2Fe + 3CO2 D CO2 + C → 2CO Fe2O3 + 3CO → 2Fe + 3CO2

Question

A sample of river water contains a high concentration of nitrates from fertilisers. Which statements about the river water are correct? 1 It has a boiling point of 100 °C. 2 Its melting point is below 0 °C. 3 It turns anhydrous cobalt(II) chloride from pink to blue. 4 It turns anhydrous copper(II) sulfate from white to blue. A 1 and 3 B 1 and 4 C 2 and 3 D 2 and 4

Question

Which statements about the treatment of domestic water supplies are correct? 1 The water undergoes sedimentation to remove dissolved solids. 2 The water is filtered to remove insoluble solids. 3 The water is treated with carbon to improve the taste. 4 The water is chlorinated to decrease the pH. A 1 and 2 B 1 and 4 C 2 and 3 D 3 and 4

Question

An experiment to find the percentage of oxygen in 150 cm3 of polluted air is shown. damp measuring cylinder iron wool 150 cm3 of polluted air water The apparatus is left for one week. After this time, the volume of gas in the measuring cylinder is 122 cm3. What is the percentage of oxygen, to the nearest whole number, in the polluted air? A 19% B 21% C 28% D 81%

Question

Nitrogen monoxide, NO, and carbon monoxide, CO, are both removed from the exhaust gases of a car by a catalytic converter. Which statement describes how nitrogen monoxide and carbon monoxide are removed by a catalytic converter? A Nitrogen monoxide and carbon monoxide are both reduced. B Nitrogen monoxide and carbon monoxide are both oxidised. C Nitrogen monoxide is oxidised and carbon monoxide is reduced. D Nitrogen monoxide is reduced and carbon monoxide is oxidised.

Question

Propan-1-ol is oxidised by acidified aqueous potassium manganate(VII) in a similar way to ethanol. Which compound is produced by the oxidation of propan-1-ol with acidified aqueous potassium manganate(VII)? A CH3CH2OH B CH3CH2CH2OH C CH3COOH D CH3CH2COOH

Question

The structural formula of methyl propane is CH3CH(CH3)CH3. The equation represents the reaction of methyl propane with chlorine. C4H10 + Cl 2 → C4H9Cl + HCl How many structural isomers with the molecular formula C4H9Cl can be formed from this reaction? A 1 B 2 C 3 D 4

Question

Which statements describe disadvantages of manufacturing ethanol by fermentation? 1 The process uses a renewable resource. 2 The process produces impure ethanol. 3 The process requires a high temperature. 4 The process is slow. A 1 and 3 B 1 and 4 C 2 and 3 D 2 and 4

Question

Nylon is made in a polymerisation reaction. Which row describes the type of polymerisation and identifies the other product of the reaction? type of other product polymerisation A addition water B addition none C condensation water D condensation none

Question

Which ion forms a green precipitate with aqueous sodium hydroxide that dissolves in an excess of aqueous sodium hydroxide? A Ca2+ B Cr3+ C Cu2+ D Fe2+

Question

A mixture of soluble substances can be separated by paper chromatography. Each substance can be identified using its Rf value. Which formula shows how the Rf value is calculated? distance travelled by solvent A Rf = distance travelled by substance distance travelled by substance B Rf = distance travelled by solvent C Rf = distance travelled by solvent – distance travelled by substance D Rf = distance travelled by solvent × distance travelled by substance 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.).