Chemistry 9701/14 May/June 2025: question paper and mark scheme

Question

The diagram shows the logarithm of the first 13 ionisation energies of an element. log ionisation energy 1 2 3 4 5 6 7 8 9 10 11 12 13 number of electrons removed Which statement is correct? A A proton is lost for each successive ionisation energy. B The element is aluminium. C The element is silicon. D The element has only one outer electron.

Question

What is the empirical formula of butanoic acid? A C2H4O B C3H6O C C4H8O D C5H10O

Question

In which pair is the bond angle in the first species smaller than the smallest bond angle in the second species? A CH4 and SF6 B CO2 and BF3 C H2O and H3O+ D NH4+ and NH3

Question

Two glass vessels, M and N, are connected by a closed valve. M N M contains helium at 20 °C at a pressure of 1 × 105 Pa. N has been evacuated, and has three times the volume of M. The valve is opened and the temperature of the whole apparatus is raised to 100 °C. What is the final pressure in the system? A 3.18 × 104 Pa B 4.24 × 104 Pa C 1.25 × 105 Pa D 5.09 × 105 Pa

Question

Solid sulfur consists of molecules made up of eight atoms covalently bonded together. The bonding in sulfur dioxide is O=S=O. enthalpy change of combustion of S8, S8(s) = –2376 kJ mol–1 energy required to break 1.0 mol S8(s) into gaseous atoms = 2232 kJ mol–1 O=O bond enthalpy = 496 kJ mol–1 Using these data, what is the value of the S=O bond enthalpy? A 239 kJ mol–1 B 257 kJ mol–1 C 319 kJ mol–1 D 536 kJ mol–1

Question

In this question, the average oxidation state of sulfur in S2O32– and sulfur in S2O42– should be used. In which reaction does the underlined element have the largest increase in oxidation state? A 3CrO43–(aq) + 8H+(aq) → 2CrO42–(aq) + Cr3+(aq) + 4H2O(l) B 2NO2(g) + H2O(l) → HNO3(aq) + HNO2(aq) C S2O32–(aq) + 2H+(aq) → S(s) + SO2(g) + H2O(l) D 2S2O42–(aq) + H2O(l) → S2O32–(aq) + 2HSO3–(aq)

Question

Methanol, CH3OH, is made industrially from carbon monoxide and hydrogen in the equilibrium reaction shown. CO(g) + 2H2(g) CH3OH(g) ΔH = –100 kJ mol–1 Which statement about this equilibrium is correct? p CH3 OH A Kp for the process is . p CO × p H 2 B An increase in pressure increases the equilibrium yield of methanol. C An increase in temperature increases the equilibrium yield of methanol. D The addition of an effective catalyst increases the equilibrium yield of methanol.

Question

The distribution of molecular energies in an ideal gas can be represented in a Boltzmann distribution. Which change in conditions leads to a larger value for the number of molecules that have the most probable energy? A keeping the temperature constant but decreasing the pressure B keeping the pressure constant but decreasing the temperature C keeping the temperature constant but increasing the pressure D keeping the pressure constant but increasing the temperature

Question

Which graph represents the number of unpaired electrons in the atoms of six elements in Period 3 of the Periodic Table? A B number of number of unpaired unpaired electrons electrons 0 0 13 14 15 16 17 18 13 14 15 16 17 18 proton number proton number C D number of number of unpaired unpaired electrons electrons 0 0 13 14 15 16 17 18 13 14 15 16 17 18 proton number proton number

Question

A 69.0 g sample of nitrogen dioxide is placed in a reaction vessel. The initial pressure of the nitrogen dioxide is P. An effective catalyst is then added and the nitrogen dioxide begins to decompose into its elements. After ten minutes, the total pressure is 1.1P. What is the mass of oxygen molecules in the reaction vessel after ten minutes? A 4.80 g B 9.60 g C 38.4 g D 48.0 g

Question

Which statement about the molecule PF5 is correct? A Every F–P–F bond angle is 90°. B The central atom in the molecule does not have a lone pair of electrons. C The molecule has an overall dipole moment. D The shape of the molecule is octahedral.

Question

Which solid compound has both ionic and covalent bonding but not coordinate bonding? A Al 2Cl 6 B CH3COONa C MgCl 2 D NH4Cl

Question

Which equation represents the standard enthalpy change of formation, , for ethanol? A 2C(s) + 2 21 H2(g) + 21 O2(g) → C2H5OH(g) B 2C(s) + 2 21 H2(g) + 21 O2(g) → C2H5OH(l) C 2C(s) + 3H2(g) + 21 O2(g) → C2H5OH(g) D 2C(s) + 3H2(g) + 21 O2(g) → C2H5OH(l)

Question

When K2MnO4 reacts with concentrated hydrochloric acid, the products include chlorine molecules and MnCl 2. All of the manganese atoms are reduced to MnCl 2. Both Mn and Cl change their oxidation numbers during the reaction. No other element is oxidised or reduced. Using these changes in oxidation number, how many moles of chlorine will be produced when 1.0 mol of K2MnO4 reacts with an excess of hydrochloric acid? A 2.0 mol B 2.5 mol C 3.0 mol D 4.0 mol

Question

A nitrogen–hydrogen mixture, initially in the mole ratio of 1 : 3, reaches equilibrium with ammonia when 50% of the nitrogen has reacted. The total final pressure is p. N2 + 3H2 2NH3 What is the partial pressure of ammonia in the equilibrium mixture? p p p p A B C D 6 4 3 2

Question

Propyl methanoate is hydrolysed with NaOH(aq) at 20 °C to form two products, X and Y. Product X is an alcohol. Data from the experiment is shown. time / s [X] / mol dm–3 0 0.000 40 0.004 80 0.007 120 0.010 180 0.015 240 0.019 300 0.022 Which row is correct? average rate of reaction product Y between 240 and 300 s A 5.00 × 10–5 mol dm–3 s–1 HCOONa B 5.00 × 10–5 mol dm–3 s–1 HCOOH C 7.33 × 10–5 mol dm–3 s–1 HCOONa D 7.33 × 10–5 mol dm–3 s–1 HCOOH

Question

The table shows the numbers of bond pairs and lone pairs in four different species. Which row is correct? total number total number species of bond pairs of lone pairs A nitrogen molecule 3 1 B ammonia molecule 4 1 C ammonium ion 4 0 D hydroxide ion 1 4

Question

Which row is correct? property explanation A AgI dissolves in aqueous ammonia AgI reacts with more readily than AgCl does aqueous ammonia B HCl decomposes Cl is more more readily than HI does electronegative than I C I2 has a higher I2 has stronger melting point than Cl 2 van der Waals’ forces than Cl 2 D I2 is a stronger oxidising an I atom loses electrons agent than Cl 2 more readily than a Cl atom

Question

Substance J reacts with water. A gas is given off and the pH of the solution increases. The solution is then reacted with sulfuric acid and a white precipitate forms. What could be substance J? A barium B barium oxide C magnesium D magnesium oxide

Question

Compound L has empirical formula NH. It decomposes on gentle heating to produce ammonia and compound M only. An aqueous solution of compound L is a good conductor of electricity. Which row could be correct? species present identity of M in L(aq) A N2H4 N3– and H+ B N2H4 NH4+ and NH2– C HN3 NH3 and HN3 D HN3 NH4+ and N3–

Question

X, Y and Z are elements in Period 3 of the Periodic Table. The results of some experiments carried out with compounds of these elements are shown. result of adding result of adding result of adding element the oxide of the the chloride of the the oxide of the element to H2O(l) element to H2O(l) element to HCl (aq) X no reaction hydrolyses forms chloride salt Y forms hydroxide dissolves forms chloride salt Z forms acid hydrolyses hydrolyses Which statement is correct? A Element X is Al and element Y is Mg. B Element X is Si and element Y is Na. C Element Y is Al and element Z is P. D Element Y is Na and element Z is Al .

Question

The flow diagram shows two successive reactions starting from element Q. Element Q is either calcium or barium. 1 heat with oxygen element Q compound R 2 add to water Element Q forms a nitrate that is less thermally stable than strontium nitrate. What is the identity of compound R? A CaO B Ca(OH)2 C BaO D Ba(OH)2

Question

Which anions are formed when chlorine is passed into cold aqueous potassium hydroxide? A Cl – and Cl O– B Cl – and Cl O3– C Cl – and Cl O4– D Cl O– and Cl O3–

Question

What increases for each successive element in Period 3 from sodium to sulfur? A the highest oxidation number of the element seen in an oxide B the melting point of the elements C the number of occupied orbitals in the atom D the pH of the solutions of the chlorides in water

Question

Which statement about an ammonium ion is correct? A All of the H–N–H bond angles in the ion are 90°. B All of the H–N–H bond angles in the ion are 107°. C The ion contains a N–H dative covalent bond which is weaker than the other three N–H covalent bonds. D The ion will react with a base as it is a weak acid.

Question

An alcohol, U, is reacted with hot acidified K2Cr2O7 solution. The organic product of the reaction contains 58.8% C, 9.8% H and 31.4% O by mass. What is the identity of alcohol U? A 2-methylbutan-2-ol B 3-methylbutan-2-ol C pentan-1-ol D propan-1-ol

Question

Which row shows a primary, a secondary and a tertiary alcohol? primary secondary tertiary CH2OH CH2OH CH2OH A CH2 CHOH CHOH CH3 CH3 CH2OH CH2OH CH3 CH3 B CH3 C H CH3 C OH CH3 C H CH3 CH3 CH2OH CH2OH CH2OH CH2OH C CH3 C H CH3 C CH2OH CH3 C CH2OH H H CH2OH H CH3 CH3 D CH3 C OH CH3 C OH CH3 C OH H H CH3 28 1-chloro-2-methylbutane reacts with sodium cyanide in a nucleophilic substitution reaction. What is the most likely intermediate or transition state in this reaction? A B – – H H H 3C CH2CH3 NC C Cl NC C Cl CH(CH3)CH2CH3 CH3 C D H 3C CH2CH3 H H +C +C CH3 CH(CH3)CH2CH3

Question

In the question paper above.

Question

When 0.010 mol of a hydrocarbon X reacts with 720 cm3 of hydrogen at room conditions, an alkane is formed. What is hydrocarbon X? A B C D

Question

An alkene reacts with hot concentrated acidified KMnO4 to produce a single organic product as shown. hot concentrated O O acidified KMnO4(aq) alkene OH What is the structure of the alkene? A B C D

Question

Testosterone is an optically active organic molecule. testosterone OH O How many chiral centres are there in one molecule of testosterone? A 5 B 6 C 7 D 8

Question

Quinone is an unsaturated molecule. quinone O O Which statement about quinone is correct? A Quinone is non-planar and has an overall dipole moment. B Quinone is non-planar and does not have an overall dipole moment. C Quinone is planar and has an overall dipole moment. D Quinone is planar and does not have an overall dipole moment.

Question

Which reagent would react with 1-bromopropane to give the highest yield of propene? A ammonia B aqueous potassium hydroxide C potassium cyanide D ethanolic sodium hydroxide

Question

Acidified potassium dichromate(VI), K2Cr2O7, is added to propan-1-ol and the mixture is immediately distilled. The distillate is treated with HCN in the presence of KCN. What is the organic product? A CH3C(CN)(OH)CH3 B CH3CH2CH2CO2H C CH3CH2CH(OH)CN D CH3CH2CH2CN

Question

Compound Q gives positive results when tested separately with alkaline I2(aq) and with Tollens’ reagent. What is compound Q? A CHOCH2CH2CHO B CH3CH2COCHO C CH3COCH2CHO D CH3COCOCH3

Question

Structural isomerism and stereoisomerism should be considered when answering this question. How many isomeric esters of methanoic acid can be made with the molecular formula C5H10O2? A 2 B 3 C 4 D 5

Question

The juice of one lemon reacts completely with 120 cm3 of 0.50 mol dm–3 sodium carbonate solution. The formula of citric acid is HOOCCH2C(OH)(COOH)CH2COOH. No sodium carbonate is left unreacted. What is the amount of citric acid in one lemon assuming that it is the only acid in the sample? A 0.02 mol B 0.04 mol C 0.06 mol D 0.09 mol

Question

Separate samples of 1-bromopropane are used in two different reactions. reaction 1 1-bromopropane is converted into compound X by heating it under pressure with ammonia in ethanol. reaction 2 1-bromopropane is converted into compound Y. Compound Y undergoes hydrolysis to form butanoic acid. Which row identifies compound X and describes the reagents used in reaction 2 to make compound Y? identity of compound X reagents for reaction 2 A CH3CH2CH2NH2 HCN(aq) B CH3CH2CH2NH2 KCN dissolved in ethanol C CH3CH2CH2OH HCN(aq) D CH3CH2CH2OH KCN dissolved in ethanol

Question

The diagram shows part of a polymer chain. H H CN H H H CN H C C C C C C C C CN H H H CN H H H Which monomer would form this polymer? A B C D H H H CN H CN H H H CN H C C C C C C C C C C C C H CN CN H H CN H CN H

Question

The mass spectrum of element Z is shown. 100 relative 50 intensity 0 30 35 40 45 50 55 60 65 70 75 80 m/e What is element Z? A arsenic B chlorine C gallium D tungsten 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 20 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 – – – – – – – – – – –