Chemistry 9701/14 October/November 2025: question paper and mark scheme

Question

Helium forms an ion 32 He +. Three statements about this ion are listed. 1 It contains two protons. 2 It contains three neutrons. 3 It contains one electron. Which statements are correct? A 1, 2 and 3 B 1 and 3 only C 2 and 3 only D 2 only

Question

The table shows the first five ionisation energies of element X. ionisation energy / kJ mol–1 element 1st 2nd 3rd 4th 5th X 736 1450 7740 10 500 13 600 Element X is in Period 3 of the Periodic Table. What is element X? A sodium B magnesium C silicon D argon

Question

Methanethiol, CH3SH, burns as shown. CH3SH + 3O2 → CO2 + SO2 + 2H2O A sample of 10 cm3 of methanethiol gas was reacted with 60 cm3 of oxygen. Both samples were measured at room conditions. What would be the final volume of the resultant mixture of gases measured at room temperature? A 20 cm3 B 30 cm3 C 50 cm3 D 70 cm3

Question

A solution containing 4.4 g of an organic acid is exactly neutralised by 25.0 cm3 of 2.0 mol dm–3 sodium hydroxide. The acid has one COOH group in each molecule. What is the empirical formula of the acid? A CH2O B C2H4O C C3H6O3 D C4H8O2

Question

In which set do all the molecules have all their atoms arranged in one plane? A Al Cl 3, BF3, PH3 B Al Cl 3, CO2, NH3 C BF3, C2H4, C3H6 D C2H4, CO2, H2O

Question

The diagram shows the bonding in a molecule of propyne. H H C C C H H Which types of hybridisation are shown by the carbon atoms in propyne? A sp, sp2 and sp3 B sp and sp3 only C sp2 and sp3 only D sp2 only

Question

The boiling point of water, H2O, is higher than that of hydrogen sulfide, H2S. Which statement explains this difference in boiling points? A The bond energy of O–H is greater than the bond energy of S–H. B The intermolecular forces in H2O are weaker than the intermolecular forces in H2S. C The S–H bond in H2S is longer than the O–H bond in H2O. D There is significant intermolecular hydrogen bonding in H2O but not in H2S.

Question

Which row describes silicon dioxide? electrical conductivity solubility in water in liquid state A non-conductor insoluble B non-conductor soluble C conductor insoluble D conductor soluble

Question

The data shown are needed for this question. (P4O10(s)) = –3012 kJ mol–1 (H2O(l)) = –286 kJ mol–1 (H3PO4(s)) = –1279 kJ mol–1 What is ΔH o for the reaction shown? P4O10(s) + 6H2O(l) → 4H3PO4(s) A –9844 kJ mol–1 B –388 kJ mol–1 C –97 kJ mol–1 D +2019 kJ mol–1

Question

In an experiment to measure the enthalpy change of neutralisation of hydrochloric acid, 20 cm3 of solution containing 0.04 mol of HCl is placed in a plastic cup of negligible heat capacity. A 20 cm3 sample of aqueous sodium hydroxide containing 0.04 mol of NaOH, at the same initial temperature, is added and the temperature rises by 15 K. If the heat capacity per unit volume of the final solution is 4.2 J K–1 cm–3, what is the enthalpy change of neutralisation of hydrochloric acid? 20 u 4.2 u 15 A J mol–1 0.04 B 40 u 4.2 u 15 u 0.08 J mol–1 40 u 4.2 u 15 C J mol–1 0.04 20 u 4.2 u 15 D J mol–1 0.08

Question

Acidified potassium manganate(VII) reacts with iron(II) ethanedioate, FeC2O4. The reactions taking place are shown. MnO4– + 8H+ + 5e– → Mn2+ + 4H2O Fe2+ → Fe3+ + e– C2O42– → 2CO2 + 2e– How many moles of iron(II) ethanedioate react with one mole of potassium manganate(VII)? A 0.60 B 1.67 C 2.50 D 5.00

Question

Nitrogen dioxide decomposes on heating according to the equation shown. 2NO2(g) 2NO(g) + O2(g) When 4 mol of nitrogen dioxide were put into a 1 dm3 container and heated to a constant temperature, the equilibrium mixture contained 0.8 mol of oxygen. What is the value of the equilibrium constant, Kc, at the temperature of the experiment? 0.82 × 0.8 1.6 × 0.8 1.62 × 0.8 1.62 × 0.8 A B C D 42 2 . 42 42 2.42

Question

One particle of X reacts with one particle of Y in a single-step reaction to produce two particles of Z. This reaction is exothermic and reversible. X + Y 2Z Three statements about the forward and reverse reactions are listed. 1 The activation energy of the forward reaction is equal to the activation energy of the reverse reaction. 2 At equilibrium, the frequency of collisions between one particle of X and one particle of Y is equal to the frequency of collisions between two particles of Z. 3 At equilibrium, the frequency of effective collisions between one particle of X and one particle of Y is equal to the frequency of effective collisions between two particles of Z. Which statements are correct? A 1 only B 2 and 3 C 2 only D 3 only

Question

When two aqueous solutions are mixed, the reaction between them is very slow. An effective catalyst is added to the mixture without any change in temperature. Which statement about this catalyst is correct? A It increases the average energy of the reactant particles. B It changes the distribution of energies of the reactant particles. C It allows a greater number of reactant particles to react per unit time. D It increases the number of reactant particles with the most probable energy.

Question

A mixture of gases reacts faster as its temperature increases. Which row explains this? more particles the activation there is an increase have energy equal energy remains in the rate of to or above the unchanged successful collisions activation energy A false false false B true true true C false true true D true false false

Question

A student investigated the chloride of a Period 3 element. This is what the student wrote down as their observations. The compound was a white crystalline solid. It dissolved easily in water to give a solution of pH 12. When placed in a test-tube and heated in a roaring Bunsen flame, the compound melted after several minutes’ heating. What can be deduced from these observations? A At least one of the recorded observations is not correct. B The compound was magnesium chloride, MgCl 2. C The compound was phosphorus pentachloride, PCl 5. D The compound was sodium chloride, NaCl.

Question

Which graph shows the relative melting points of the elements Mg, Al, Si and P plotted against their relative electronegativities? A B Si Al melting point Mg melting point Mg Al Si P P electronegativity electronegativity C D Si Al melting point Al Mg melting point Mg Si P P electronegativity electronegativity

Question

Caesium and barium are in Period 6 of the Periodic Table. Which row is correct? the larger the higher ionic radius melting point A Ba2+ barium B Ba2+ caesium C Cs+ barium D Cs+ caesium

Question

Magnesium nitrate, Mg(NO3)2, will decompose when heated to give a white solid and a mixture of gases. One of the gases released is oxygen. 29.7 g of anhydrous magnesium nitrate is heated until no further reaction takes place. Which mass of oxygen is produced? A 3.2 g B 6.4 g C 12.8 g D 19.2 g

Question

Which row shows the trends in the named properties going down the Group 2 nitrates? volume of gas produced, measured at room conditions, thermal stability when 1.0 g of anhydrous solid nitrate is thermally decomposed A increases increases B increases decreases C decreases increases D decreases decreases

Question

X, Y and Z are three aqueous solutions. Equal volumes of pairs of the solutions are mixed and observations noted. X mixed with Y shows no reaction. X mixed with Z shows an immediate reaction. Z mixed with Y shows no reaction. What are X, Y and Z? X Y Z A Br2(aq) I2(aq) HBr(aq) B Cl 2(aq) I2(aq) HBr(aq) C HCl (aq) HI(aq) Br2(aq) D HCl (aq) Br2(aq) HBr(aq)

Question

An excess of chlorine gas is bubbled into hot potassium hydroxide solution. Which chlorine-containing species are present in the final solution? A Cl – and Cl O– B Cl – and Cl O3– C Cl O– and Cl O3– D Cl O3– only

Question

The oxides of nitrogen, NO and NO2, act as pollutants in the Earth’s atmosphere in a number of different ways. Three statements about the oxides of nitrogen are listed. 1 They react with oxygen and water vapour to form nitric acid, a constituent of acid rain. 2 They react with carbon monoxide to form photochemical smog. 3 They catalyse the oxidation of sulfur dioxide in the formation of sulfuric acid, another constituent of acid rain. Which statements are correct? A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only

Question

Which reagent, when mixed with ammonium sulfate and then heated, liberates ammonia? A aqueous bromine B dilute hydrochloric acid C aqueous calcium hydroxide D potassium dichromate(VI) in acidic solution

Question

Two hydrocarbons, CH3CHC(CH3)CH3 and CH3CH(CH3)CH2CH3, react separately with chlorine in the presence of ultraviolet light. In each reaction, free-radical substitution occurs. Which row is correct? identity of the hydrocarbon a termination stage of the free-radical that can also undergo substitution of the saturated hydrocarbon electrophilic addition A CH3CHC(CH3)CH3 CH3CH(CH3)CH2CH2• + Cl • → CH3CH(CH3)CH2CH2Cl B CH3CHC(CH3)CH3 CH3CHC(CH3)CH2• + Cl • → CH3CHC(CH3)CH2Cl C CH3CH(CH3)CH2CH3 CH3CH(CH3)CH2CH2• + Cl • → CH3CH(CH3)CH2CH2Cl D CH3CH(CH3)CH2CH3 CH3CHC(CH3)CH2• + Cl • → CH2CHC(CH3)CH2Cl

Question

The structure of the compound γ-ionone is shown. J-ionone O Including γ-ionone, how many stereoisomers exist with this molecular formula? A 1 B 2 C 4 D 8

Question

Structural and stereoisomerism should be considered when answering this question. A mixture of 1-chlorobutane and 2-chlorobutane is heated with an excess of NaOH in ethanol. How many different organic molecules will be produced? A 1 B 2 C 3 D 4

Question

The diagram shows the skeletal formula of the hormone testosterone. OH O What is the molecular formula of testosterone? A C19H28O2 B C17H22O2 C C17H24O2 D C19H26O2

Question

Pinenes are unsaturated compounds. The structures of two pinenes are shown. D-pinene E-pinene A mixture of these two pinenes reacts with hot concentrated acidified KMnO4. What are the molecular formulae of the organic products? A C9H14O and C10H16O3 B C9H14O and C10H14O4 C C9H16O2 and C10H16O3 D C9H16O2 and C10H14O4

Question

An organic ion containing a carbon atom with a negative charge is called a carbanion. An organic ion containing a carbon atom with a positive charge is called a carbocation. The reaction between NaOH(aq) and 1-bromobutane proceeds by an SN2 mechanism. What is the first step in the mechanism? A attack by a nucleophile on a carbon atom with a partial positive charge B heterolytic bond fission followed by attack by an electrophile on a carbanion C heterolytic bond fission followed by attack by a nucleophile on a carbocation D homolytic bond fission followed by attack by a nucleophile on a carbocation 31 2-chloropropane and 2-bromopropane react separately with aqueous NaOH. Which row is correct? comparison of explanation of the rates of reaction difference in reaction rates A 2-chloropropane chlorine is more reacts faster reactive than bromine B 2-chloropropane the C–Cl bond is more reacts faster polar than the C–Br bond C 2-bromopropane the first ionisation energy of reacts faster bromine is lower than chlorine’s D 2-bromopropane the C–Br bond is reacts faster weaker than the C–Cl bond

Question

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Question

The diagram shows the structure of compound X. Br Br Br X X undergoes hydrolysis to form product Y in which all of the bromine atoms are replaced by hydroxyl groups. Product Z is formed by oxidation of Y. Two suggestions are listed. 1 Y is a secondary alcohol. 2 Z is a ketone. Which suggestions are correct? A both 1 and 2 B 1 only C 2 only D neither 1 nor 2

Question

Cyclohexanol is converted to cyclohexane-1,2-diol via a two-step synthesis that proceeds via intermediate Q. OH OH step 1 step 2 Q OH Which row identifies the type of reaction in step 1 and in step 2? step 1 step 2 A dehydration oxidation B dehydration nucleophilic substitution C reduction oxidation D reduction nucleophilic substitution

Question

Three tests were performed on an unknown organic compound. test reagent test result 2,4-DNPH reagent orange ppt Tollens’ reagent no change alkaline I2(aq) yellow ppt What is the organic compound tested? A B C D I I O O O O O

Question

Butanone, CH3CH2COCH3, and HCN mixed with a little KCN react together in a nucleophilic addition reaction. Which description of the mechanism of this nucleophilic addition reaction is correct? A The π bond pair of C=O accepts H+ from HCN and then CN– acts as a nucleophile. B A π bond pair from CN– attacks the δ+ C and HCN then donates H+ to O. C The lone pair on O accepts H+ from HCN and then CN– acts as a nucleophile. D A lone pair from CN– attacks the δ+ C and then O– accepts H+ from HCN.

Question

The structural formula of compound P is CH3CH2COOCH2CH3. P can be formed by reacting together two organic compounds in the presence of a suitable catalyst. Which pair of compounds could react together to produce P? A ethanoic acid and propanoic acid B ethanoic acid and propan-1-ol C ethanol and propanoic acid D ethanol and propan-1-ol

Question

The structures of three organic compounds are shown. H H H O H H C C O H C C N H C C O C H H H H H H 1 2 3 Which compounds produce ethanoic acid when heated with HCl (aq)? A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only

Question

When bromoethane, C2H5Br, is heated with NaOH in ethanol, which type of reaction occurs? A electrophilic substitution B elimination C nucleophilic substitution, mainly via an SN1 mechanism D nucleophilic substitution, mainly via an SN2 mechanism

Question

PMMA is a rigid polymer. The repeat unit of PMMA is shown. H CH3 C C H CO2CH3 n Which monomer is used to make PMMA? A B C D CH3 CH3 CH3 CH3 OH OH O O H 3C H 2C H 3C CH3 H2 C CH3 O O O O

Question

A sample of gallium contains two isotopes only. In every 10 atoms in the sample, there are 6 that have 38 neutrons and 4 that have 40 neutrons. What is the relative atomic mass, Ar, of the gallium in the sample? A 69.7 B 69.8 C 70.0 D 70.2 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 = 6.02 × 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 – – – – – – – – – – –