Chemistry 9701/12 May/June 2025: question paper and mark scheme

Question

Consider the following statements. 1 Silicon dioxide has a higher melting point than sulfur dioxide. 2 Ammonia has a higher boiling point than phosphine, PH3. Which statements are correct? A both statement 1 and statement 2 B statement 1 only C statement 2 only D neither statement 1 nor statement 2

Question

How many neutrons are contained in an atom of iron with a mass number of 60? A 26 B 30 C 34 D 60

Question

The diagram shows a Boltzmann distribution of molecular energies for a gaseous reaction at two different temperatures and two different activation energies. T1 T2 proportion of molecules EA(1) EA(2) energy / kJ mol–1 Which combination of temperature and activation energy will give the highest reaction rate? A T1 and EA(1) B T1 and EA(2) C T2 and EA(2) D T2 and EA(1)

Question

The reaction between sulfur dioxide and oxygen has the equation shown. 2SO2(g) + O2(g) 2SO3(g) ΔH = –197 kJ mol–1 1.0 mol of SO2 and 1.0 mol of O2 are placed in a closed container and heated to a constant temperature. At this temperature, 0.8 mol of SO3 are present in the equilibrium mixture. Which statement is correct? A The equilibrium partial pressure of SO2 is greater than the equilibrium partial pressure of O2. B Kp has units of mol dm–3. C At a lower temperature, the equilibrium amount of SO3 is lower than 0.8 mol. D The mole fraction of SO3 is less than 0.8.

Question

‘Red lead’ is a red pigment with the formula Pb3O4. Every formula unit of ‘red lead’ is the same. Each formula unit contains three lead ions and four oxide ions. Lead has two different oxidation states in ‘red lead’. What are the oxidation states of lead in ‘red lead’? A +1 and +2 B +1 and +3 C +2 and +4 D +2 and +6

Question

Some standard enthalpy of combustion data are given. standard enthalpy change substance of combustion / kJ mol–1 C(s) –394 H2(g) –286 CH3OH(l) –726 Using these data, what is the enthalpy change of formation of methanol? A –240 kJ mol–1 B –46 kJ mol–1 C 46 kJ mol–1 D 240 kJ mol–1

Question

Which row is correct? smallest largest bond angle bond angle A H2O NH3 BF3 B BF3 NH3 H2O C NH3 H2O BF3 D H2O BF3 NH3

Question

In the Haber process, the reaction between the two gaseous reactants requires the use of a catalyst that contains a transition element. What is the metal and in which mole ratio do the gases react? metal mole ratio A Fe 1:2 B Fe 1:3 C V 1:2 D V 1:3

Question

Aqueous hydrogen peroxide, H2O2, decomposes into water and oxygen in the presence of a suitable catalyst. 50 cm3 of a 0.50 mol dm–3 solution of hydrogen peroxide produced 120 cm3 of oxygen in 2.0 minutes. The volume of gas was measured at room conditions. What is the average rate of decomposition of hydrogen peroxide during this 2.0 minute period? A 0.000083 mol dm–3 s–1 B 0.00083 mol dm–3 s–1 C 0.0017 mol dm–3 s–1 D 0.10 mol dm–3 s–1

Question

The average intermolecular forces in water are much stronger than the average intermolecular forces in steam. The average intermolecular forces in ice are slightly stronger than the average intermolecular forces in water. Enthalpy changes are associated with the equilibrium processes shown. H2O(l) H2O(g) ΔHb H2O(s) H2O(l) ΔHm Which statements are correct? 1 ΔHb and ΔHm are both negative. 2 ΔHb is greater than ΔHm. 3 The intermolecular forces in ice and water are of the same type. A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only

Question

An experiment is carried out to determine the value of x in hydrated lithium hydroxide, LiOH•xH2O. A sample of the solid is heated in a crucible over a Bunsen flame. Complete dehydration takes place; decomposition does not occur. mass of empty crucible / g = Q mass of crucible with LiOH•xH2O / g = R mass of crucible and residue after heating / g = S Which equation gives the correct value of x? S–R R –S 23.9( R – S ) 23.9( S – R ) A B C D 18 18 18(S – Q ) 18(S – Q )

Question

A sample of an ideal gas occupies 240 cm3 at 37 °C and 100 kPa. How many moles of gas are present in the sample? A 9.32 × 10–6 B 9.32 × 10–3 C 0.0781 D 78.1

Question

Under certain conditions, CCl 4 and H2O react as shown. The activation energy for the reaction is +62 kJ mol–1. CCl 4 + 2H2O → CO2 + 4HCl ΔH = –61.5 kJ mol–1 Which enthalpy profile diagram best fits this reaction? A B CCl 4 + 2H2O CO2 + 4HCl enthalpy CO2 + 4HCl enthalpy CCl 4 + 2H2O reaction path reaction path C D CO2 + 4HCl CCl 4 + 2H2O enthalpy enthalpy CO2 + 4HCl CCl 4 + 2H2O reaction path reaction path

Question

A helium ion contains two protons, two neutrons and one electron. This helium ion and a proton are passed separately through a uniform electric field. The particles are travelling at the same velocity. Which arrow describes the path of each particle? 1 5 + 2 4 – 3 helium ion proton A 1 2 B 2 1 C 4 5 D 5 4

Question

The skeletal formulae of arginine and lysine are shown. arginine lysine NH O O H 2N H 2N N OH OH H NH2 NH2 Which row is correct? substance empirical formula Mr A arginine C3H7N2O 174 B arginine C3H8N2O 176 C lysine C3H7NO 144 D lysine C3H8NO 146

Question

The oxide and chloride of an element X are separately mixed with water. The two resulting solutions have the same effect on litmus. What could element X be? A Al B Ca C Na D P

Question

Why do the halogens become less volatile as Group 17 is descended? A The halogen–halogen bond energy decreases. B The halogen–halogen bond energy increases. C The number of electrons in each molecule increases. D The van der Waals’ forces between molecules become weaker.

Question

Compound M is a white solid. It is the chloride of a Period 3 element. Information about some reactions starting with compound M is given in the table. reaction observation compound M + non-polar solvent colourless solution compound M added a little at a time to water steamy fumes, Q colourless solution, R fumes Q tested with moist blue litmus paper paper turns red solution R + a few drops of NaOH(aq) white precipitate + excess NaOH(aq) dissolves to give a colourless solution What is compound M? A aluminium chloride B magnesium chloride C phosphorus pentachloride D sodium chloride

Question

Which statement about strontium and its compounds is correct? A Strontium hydroxide is more soluble than barium hydroxide. B Strontium sulfate is more soluble than magnesium sulfate. C Strontium nitrate has a lower thermal stability than calcium nitrate. D Strontium is a stronger reducing agent than magnesium.

Question

Sodium bromide is warmed with concentrated sulfuric acid. Which row describes the change in the oxidation number of the sulfur and the role of the bromide ions in the reaction? change in role of oxidation number bromide ions of sulfur A +6 to +4 oxidising agent B +6 to +4 reducing agent C +4 to 0 oxidising agent D +4 to 0 reducing agent

Question

A reaction occurs when ammonium chloride is added to calcium hydroxide. What is the role of the ammonium ions in this reaction? A acid B base C oxidising agent D reducing agent

Question

Elements Y and Z are both in Period 3. Element Y has the smallest atomic radius in Period 3. There are only two elements in Period 3 that have a lower melting point than element Z. Elements Y and Z react together to form compound R. Which compound could be R? A MgCl 2 B MgS C Na2S D PCl 3 23 1.0 g of each of four different compounds of Group 2 elements are thermally decomposed. The residue in each decomposition is the oxide of the Group 2 element. The volume of gas produced from each reaction is measured at room conditions. Which substance produces the greatest volume of gas? A calcium carbonate B calcium nitrate C strontium carbonate D strontium nitrate

Question

In the question paper above.

Question

Sulfur dioxide in the atmosphere can form acid rain. This occurs in two steps. 1 oxidation of SO2 to SO3 2 formation of dilute H2SO4 Which row identifies the atmospheric catalyst for step 1 and the reagent for step 2? catalyst reagent A O2 H2O B O2 O2 C NO2 H2O D NO2 O2

Question

Which statement about the mechanism of an SN1 reaction of a halogenoalkane is correct? A A nucleophile is substituted by an electrophile. B One intermediate is formed from two reacting molecules. C The intermediate is stabilised by adjacent alkyl groups. D The intermediate is uncharged.

Question

The repeat unit of a polymer is shown. H H H H C C C C H Cl H OH n Three statements about this polymer are listed. 1 Its disposal is hazardous because it produces toxic gases when burned. 2 Two different monomers are used to make this polymer. 3 The monomer for this polymer is 3-chlorobut-2-ene-1-ol. Which statements are correct? A 1 and 2 B 1 and 3 C 1 only D 2 only

Question

Methanoic acid, HCO2H, has acidic properties similar to those of other carboxylic acids. In addition, it can be oxidised by the same oxidising agents that are capable of oxidising aldehydes. Which pair consists of two compounds that will give the same observations with Fehling’s reagent? A HCO2H and CH3CO2H B HCO2H and CH3CO2CH3 C HCO2H and CH3CH2COCH3 D HCO2H and CH3CH2CHO

Question

Which row gives pentanenitrile as one product? reagents and halogenoalkane conditions A Br heat with HCN heat with KCN using B Br ethanol as solvent C Br heat with HCN heat with KCN using D Br ethanol as solvent

Question

An ester, R'CO2R", is hydrolysed in alkaline conditions. R' and R" are different alkyl groups. Which row identifies the two products formed? product 1 product 2 A R'CO2H R"OH B R'CO2– R"OH C R'CO2H R"O– D R'CO2– R"O–

Question

Which compound cannot be oxidised by acidified potassium dichromate(VI) solution but does react with sodium metal? A (CH3)3COH B CH3COCH2CH3 C CH3CH2CH2CH2OH D CH3CH2CH(OH)CH3

Question

Butan-2-one reacts with alkaline I2(aq). An excess of dilute sulfuric acid is then added to the reaction mixture. The organic products of this reaction sequence are triiodomethane and product M. What is product M? A ethanoate ion B ethanoic acid C propanoate ion D propanoic acid

Question

Four reagents are listed. 1 aqueous KCl 2 dilute HCl 3 liquid SOCl 2 4 solid PCl 5 Which reagents, when added to ethanol, will rapidly produce a gas that turns blue litmus red? A 1 and 2 B 1 and 3 C 2 and 4 D 3 and 4

Question

Four drops of 1-chlorobutane, 1-bromobutane and 1-iodobutane are put separately into three test-tubes containing 1.0 cm3 of aqueous silver nitrate at 60 °C. In each case, a hydrolysis reaction occurs. H2O(l) + R–X(l) + Ag+(aq) → R–OH(aq) + AgX(s) + H+(aq) R represents C4H9 and X represents the halogen atom. The rate of formation of cloudiness in the test-tubes is in the order RCl < RBr < RI. Why is this? A The bond energy of R–X decreases from RCl to RI. B The first ionisation energy of the halogen decreases from Cl to I. C The solubility of AgX(s) decreases from AgCl to AgI. D The R–X bond polarity decreases from RCl to RI.

Question

Propanoic acid reacts with LiAl H4 to give organic product P. Methanoic acid reacts with organic product P, in the presence of a few drops of concentrated sulfuric acid, to give organic product Q. What are the skeletal formulae of the two organic products? organic product P organic product Q O A OH O O B OH O O C O O O D O O

Question

Samples of the gases CH3Cl and Cl 2 are mixed together and irradiated with ultraviolet light. Which compound is produced by a termination step in the reaction? A HCl B CH2=CH2 C CH2Cl CH2Cl D H2

Question

Propan-1-ol, C3H7OH, is dehydrated by passing its vapour over hot aluminium oxide to give a hydrocarbon. Which structural formula represents the product obtained when the hydrocarbon reacts with bromine? A B H H H H Br H H C C C Br H C C C H H H H H H H C D H H Br H Br Br H C C C Br H C C C H H H H H H H

Question

Alkane S has molecular formula C4H10. S reacts with Cl 2(g) in the presence of sunlight to produce only two different monochloroalkanes, C4H9Cl. Both of these monochloroalkanes are treated with hot ethanolic KOH. They both produce the same alkene T, and no other organic products. What is produced when T is treated with hot concentrated acidified KMnO4? A CO2 and CH3CH2CO2H B CO2 and CH3COCH3 C HCO2H and CH3COCH3 D CH3CO2H only

Question

Including structural isomers and stereoisomers, how many isomers are there of C2H2Br2? A 2 B 3 C 4 D 5

Question

Which compound exhibits stereoisomerism? A 1,1-dichloropropene B 2,3-dichloropropene C 1,2-dichloropropane D 1,3-dichloropropane

Question

The mass spectrum of CH3Cl shows a molecular ion peak, M+, at the m / e value of 50 with a relative abundance of 18.0%. Other peaks are present in the mass spectrum. What is seen in the mass spectrum at the m / e value of 52? A a peak with relative abundance of 4.5% B a peak with relative abundance of 6.0% C a peak with relative abundance of 18.0% D a peak with relative abundance of 54.0% Important values, constants and standards molar gas constant R = 8.31 J K–1 mol–1 Faraday constant F = 9.65 × 104 C mol–1 Avogadro constant L = 6.022 × 1023 mol–1 electronic charge e = –1.60 × 10–19 C molar volume of gas Vm = 22.4 dm3 mol–1 at s.t.p. (101 kPa and 273 K) Vm = 24.0 dm3 mol–1 at room conditions ionic product of water Kw = 1.00 × 10–14 mol2 dm–6 (at 298 K (25 °C)) specific heat capacity of water c = 4.18 kJ kg–1 K–1 (4.18 J g–1 K–1) The Periodic Table of Elements Group 1 2 13 14 15 16 17 18 1 2 H He hydrogen helium Key 1.0 4.0 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 6.9 9.0 relative atomic mass 10.8 12.0 14.0 16.0 19.0 20.2 11 12 13 14 15 16 17 18 Na Mg Al Si P S Cl Ar sodium magnesium aluminium silicon phosphorus sulfur chlorine argon 23.0 24.3 3 4 5 6 7 8 9 10 11 12 27.0 28.1 31.0 32.1 35.5 39.9 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 39.1 40.1 45.0 47.9 50.9 52.0 54.9 55.8 58.9 58.7 63.5 65.4 69.7 72.6 74.9 79.0 79.9 83.8 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 16 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 85.5 87.6 88.9 91.2 92.9 95.9 – 101.1 102.9 106.4 107.9 112.4 114.8 118.7 121.8 127.6 126.9 131.3 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 132.9 137.3 178.5 180.9 183.8 186.2 190.2 192.2 195.1 197.0 200.6 204.4 207.2 209.0 – – – 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 138.9 140.1 140.9 144.2 – 150.4 152.0 157.3 158.9 162.5 164.9 167.3 168.9 173.1 175.0 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 – 232.0 231.0 238.0 – – – – – – – – – – –