Chemistry 9701/13 May/June 2025: question paper and mark scheme

Question

Which isolated gaseous atom has a total of five electrons occupying spherically shaped orbitals? A sodium B fluorine C boron D potassium

Question

Diagram 1 shows the reaction pathway for a reaction. Diagram 2 shows a graph of concentration of reactant against time for the same reaction. diagram 1 diagram 2 EA enthalpy reactants concentration products reaction progress time Which diagrams, drawn to the same scale, show the effect of increased temperature on this reaction? EA A enthalpy reactants concentration products reaction progress time EA B enthalpy reactants concentration products reaction progress time EA C enthalpy reactants concentration products reaction progress time EA D enthalpy reactants concentration products reaction progress time

Question

The equation shows the overall reaction between an amine and an acid chloride. 2CH3CH2NH2 + CH3CH2COCl → CH3CH2CONHCH2CH3 + CH3CH2NH3Cl The four steps in the mechanism are as follows. H H2NCH2CH3 H N+ CH2CH3 1 CH3CH2C Cl o CH3CH2C Cl O – O H H H N+ CH2CH3 2 o CH3CH2C N+ CH2CH3 + Cl – CH3CH2C Cl O H – O H Cl – CH3CH2C N CH2CH3 + HCl 3 CH3CH2C N+ CH2CH3 o O H O H H Cl 4 CH3CH2NH2 o CH3CH2NH3Cl Which steps are Brønsted–Lowry acid–base reactions? A 1 and 3 B 3 and 4 C 3 only D 4 only

Question

Chromium is present in compound X. ● Two moles of compound X react with exactly 3 moles of silicon. ● The only products of this reaction are 4 moles of chromium and 3 moles of a silicon compound in which the oxidation state of the silicon is +4. ● Chromium and silicon are the only elements that change their oxidation states in this reaction. What could be the identity of compound X? A Cr2O3 B Cr2H6 C Cr2H4 D Cr2O4

Question

The reversible reaction shown is in equilibrium at a temperature of 450 °C. H2 + I2 2HI ΔH = –9.5 kJ mol–1 The table shows the equilibrium concentrations in the reaction mixture. H2 I2 HI 1.02 mol dm–3 0.02 mol dm–3 0.98 mol dm–3 The temperature of the reaction mixture is increased at constant volume. The concentration of one of the components falls to 0.80 mol dm–3 at equilibrium under these conditions. What is the concentration of H2 in the new equilibrium mixture? A 0.80 mol dm–3 B 0.93 mol dm–3 C 1.11 mol dm–3 D 1.20 mol dm–3

Question

The first stage in the industrial production of nitric acid from ammonia can be represented by the following equation. 4NH3(g) + 5O2(g) 4NO(g) + 6H2O(g) Using the following standard enthalpy change of formation data, what is the value of the standard enthalpy change, ΔH o, for this reaction? compound NH3(g) –46.1 NO(g) +90.3 H2O(g) –241.8 A +905.2 kJ mol–1 B –105.4 kJ mol–1 C –905.2 kJ mol–1 D –1274.0 kJ mol–1

Question

The gaseous compound Z decomposes on heating. In the diagram, Boltzmann distributions for Z at two different temperatures, P and Q, are shown. The lines X and Y indicate activation energies for the decomposition of Z with and without a catalyst. P X Y number of molecules Q 0 0 molecular energy Which curve and which line describe the decomposition of Z at a higher temperature and with a catalyst present? higher catalyst temperature present A P X B P Y C Q X D Q Y

Question

The structure of a molecule found in food is shown. CH2OH O OH OH OH OH Four statements about the molecule are listed. 1 This molecule contains only σ bonds. 2 This molecule contains both σ and π bonds. 3 The six-membered ring is planar. 4 The six-membered ring is non-planar. Which two statements are correct? A 1 and 3 B 1 and 4 C 2 and 3 D 2 and 4

Question

In which substance are covalent bonds broken as it melts? A silicon(IV) oxide B ice C iodine D ethanol

Question

Why is the second ionisation energy of sodium larger than the second ionisation energy of magnesium? A The attraction between the nucleus and the outer electron is greater in Na+ than in Mg+. B The nuclear charge of Na+ is greater than that of Mg+. C The outer electron of Na+ is more shielded than the outer electron of Mg+. D The outer electron of Na is in the same orbital as the outer electron of Mg.

Question

BF3 reacts with NH3 to form a single compound with a simple molecular structure. BF3 + NH3 → F3B–NH3 Which row describes how the bond angles change during the reaction? F–B–F bond angle H–N–H bond angle A decreases decreases B decreases increases C increases decreases D increases increases

Question

The equation for the reaction of nitrogen with hydrogen is shown. N2(g) + 3H2(g) 2NH3(g) = –92.2 kJ mol–1 Which statement is correct? A is measured at 298 °C. B is measured at 101 kPa. C represents the standard enthalpy change for the formation of ammonia gas. D represents the enthalpy change when 1.0 mol of N2(g) reacts with 1.0 mol of H2(g).

Question

Hydrogen peroxide, H2O2, decomposes into water and oxygen when a suitable catalyst is added. 20.0 cm3 of aqueous hydrogen peroxide decomposes to produce 600 cm3 of oxygen at room conditions. What is the concentration of the aqueous hydrogen peroxide? A 5.00 mol dm–3 B 2.50 mol dm–3 C 1.25 mol dm–3 D 0.625 mol dm–3

Question

When 0.15 g of an organic compound is vaporised, it occupies a volume of 65.0 cm3 at 405 K and 1.00 × 105 Pa. Using the expression pV = nRT, which expression should be used to calculate the relative molecular mass, Mr, of the compound? 0.15 u 65 u 10–6 u 1 u 105 A 8.31 u 405 0.15 u 8.31 u 405 B 1 u 105 u 65 u 10–3 0.15 u 65 u 10–3 u 1 u 105 C 8.31 u 405 0.15 u 8.31 u 405 D 1 u 105 u 65 u 10–6

Question

A washing powder contains sodium hydrogencarbonate, NaHCO3, as one of the ingredients. In a titration, a solution containing 1.00 g of this washing powder requires 7.15 cm3 of 0.100 mol dm–3 sulfuric acid for complete reaction. The sodium hydrogencarbonate is the only ingredient that reacts with the acid. What is the percentage by mass of sodium hydrogencarbonate in the washing powder? A 3.0% B 6.0% C 12.0% D 24.0%

Question

The flow chart shows some reactions of nitrogen compounds. acid alkali gas 1 salt 1 salt 2 + other products Which row identifies gas 1 and salt 2? gas 1 salt 2 A ammonia ammonium nitrate B ammonia sodium nitrate C nitrogen dioxide ammonium nitrate D nitrogen dioxide sodium nitrate

Question

Mixing aqueous silver nitrate and aqueous sodium chloride produces a precipitate. Addition of which reagent to the mixture gives a colourless solution? A aqueous ammonia B aqueous potassium iodide C dilute hydrochloric acid D dilute nitric acid

Question

Which statement is correct? A Barium oxide reacts with water at room temperature to form barium hydroxide and hydrogen. B Calcium oxide does not react with water at room temperature. C Magnesium hydroxide reacts with steam to form magnesium oxide and hydrogen. D Strontium oxide reacts with water at room temperature to form strontium hydroxide only.

Question

Which statement about the properties of halogens and hydrogen halides is correct? A A chloride ion is a stronger reducing agent than an iodide ion. B Chlorine is more volatile than bromine because chlorine has stronger intermolecular forces. C Hydrogen bromide is more thermally stable than hydrogen iodide because it has a stronger covalent bond. D Iodine is less reactive than bromine because iodine has weaker covalent bonds.

Question

Three statements about the chemical periodicity of Period 3 oxides are listed. 1 The maximum oxidation state of the Period 3 elements in their oxides increases from sodium to phosphorus, then decreases from phosphorus to sulfur. 2 The oxides from sodium to aluminium dissolve in water without hydrolysis; from silicon to sulfur they are hydrolysed by water. 3 The structure and bonding changes from giant ionic to giant covalent to simple molecular. Which statements are correct? A 1, 2 and 3 B 1 only C 2 and 3 only D 3 only

Question

Which dot-and-cross diagrams represent molecules that can react with unburned hydrocarbons to form peroxyacetyl nitrate, PAN, a component of photochemical smog? 1 2 3 4 A 1 and 3 B 1 and 4 C 2 and 3 D 2 and 4

Question

Which set of three elements contains a single element that has both the highest melting point and the lowest electrical conductivity of the three elements in the set? A magnesium, aluminium and silicon B aluminium, silicon and phosphorus C sodium, magnesium and aluminium D silicon, phosphorus and chlorine

Question

In which row do the particles increase in size? smallest largest A N O F B N3– O2– F– C Na+ Mg2+ Al 3+ D Na+ Ne F–

Question

W, X, Y and Z are Group 2 elements barium, calcium, magnesium and strontium but not in that order. W reacts faster with dilute hydrochloric acid than Y. The hydroxide of X is less soluble in water than the hydroxide of W. The sulfate of Y is the most soluble of the sulfates of W, X, Y and Z. The carbonate of Z decomposes more slowly than the carbonate of W at the same temperature. What is the Mr of the nitrate of W? A 148.3 B 164.1 C 211.6 D 261.3

Question

Polymer J has repeat unit –[CH(C2H5)CH(CH3)]–. Polymer K has repeat unit –[CH(CH3)CH(CH3)]–. Which row is correct? monomer from monomer from which polymer J which polymer K is produced is produced A pent-1-ene but-1-ene B pent-1-ene but-2-ene C pent-2-ene but-1-ene D pent-2-ene but-2-ene 26 0.200 mol ethanenitrile reacts with an excess of dilute sodium hydroxide. The reaction produces organic compound S and ammonia gas only. The reaction has an 80.0% yield. Which mass of S is produced? A 9.60 g B 13.1 g C 15.4 g D 16.4 g

Question

In the question paper above.

Question

The structure of butenedioic acid is shown. butenedioic acid O HO OH O When an excess of NaOH(aq) is added to butenedioic acid, which organic product is formed? A B O OH O – O HO O– OH O O C D OH O O – HO O OH OH O OH O

Question

Four organic compounds are shown. O O O O O O O O A mixture of these four compounds reacts with hot aqueous sodium hydroxide. The products of this reaction are acidified. Which organic acids are present in the products? A butanoic, ethanoic and propanoic acids B butanoic, ethanoic and methanoic acids C ethanoic, 3-methylbutanoic and propanoic acids D methanoic, 3-methylbutanoic and propanoic acids

Question

Ethanal reacts with KCN dissolved in liquid HCN. This reaction involves the formation of an intermediate. Which statement is correct? A HCN does not have any lone pairs of electrons and so CN– is the catalyst. B The Oδ– of C=O attacks K+ in a nucleophilic attack. C A proton from HCN is transferred to the intermediate. D The reaction is a nucleophilic substitution.

Question

What is formed when propanone is heated under reflux with a solution of NaBH4? A propan-2-ol B propan-1-ol C propanal D propane

Question

The compounds shown are all produced by plants. Each compound is warmed with acidified K2Cr2O7. Which compound will give a different observation to the other three? A B C D OH OH OH OH

Question

Structural and stereoisomerism should be considered when answering this question. How many alcohols with the molecular formula C5H12O give a yellow precipitate with alkaline I2(aq)? A 2 B 3 C 4 D 5

Question

An amine is produced in the following reaction. C2H5I + 2NH3 → C2H5NH2 + NH4I What is the mechanism? A electrophilic addition B free-radical substitution C nucleophilic addition D nucleophilic substitution

Question

The reaction shown can be used to lengthen a carbon chain. CH3CH2CH2Br + CN– → CH3CH2CH2CN + Br– Which row shows the correct reagent and conditions for this reaction? reagent conditions A KCN heat under reflux in dilute sulfuric acid B KCN heat under reflux in ethanol C HCN heat under reflux in dilute sulfuric acid D HCN heat under reflux in ethanol

Question

Which row shows the products formed when cyclohexene reacts with acidified KMnO4 under different conditions? product formed on reaction with product formed on reaction with cold, dilute acidified KMnO4 hot, concentrated acidified KMnO4 OH O HO A OH OH O O OH HO B OH OH O O O H C H O O O O H D H O O

Question

Two steps in the free-radical substitution reaction between methane and chlorine are shown. step 1 CH3• + Cl 2 → CH3Cl + Cl • step 2 CH3Cl + Cl • → CH2Cl • + HCl Which statement is correct? A Step 1 is initiation and step 2 is propagation. B Step 1 is propagation and step 2 is termination. C Step 1 is initiation and step 2 is termination. D Both steps are propagation.

Question

Compound P displays cis/trans isomerism and gives a red-brown precipitate with Fehling’s solution. What is P? A B C D H CH2CHO H COCH3 H CH3 CH3 H C C C C C C C C H CH3 CH3 H H CHO H CHO

Question

Fructose is a sugar with more than one chiral centre. The fructose molecule is shown with X, Y and Z indicating three carbon atoms. fructose OH H C H X C O HO C H H C OH Y H C OH H C H Z OH Which carbon atoms are chiral centres? A X, Y and Z B X and Y only C X only D Y only

Question

An organic compound, T, contains only one functional group. Compound T has the empirical formula C2H4O. Some functional groups are listed. 1 alcohol 2 aldehyde 3 ester 4 ketone Which functional groups are possible for compound T? A 1 and 3 B 1 and 4 C 2 and 3 D 2 and 4

Question

The mass spectrum of an organic compound has the following features. ● The molecular ion peak is at m / e = 60. This peak has a relative intensity = 100. ● There is a peak at m / e = 61, which has a relative intensity = 2.2. ● There is no fragment peak at m / e = 17. ● There is a fragment peak at m / e = 31. What could be the identity of the organic compound? A methyl methanoate, HCOOCH3 B methoxyethane, CH3OC2H5 C ethanoic acid, CH3COOH D propan-2-ol, CH3CH(OH)CH3 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 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 – – – – – – – – – – –