A Level Chemistry 9701 Paper 12, May/June 2025

Consider the following statements. 1 Silicon dioxide has a higher melting point than sulfur dioxide. 2 Ammonia has a higher boiling point than phosphine, $\mathrm{P}{\mathrm{H}}_3$. 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

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

The diagram shows a Boltzmann distribution of molecular energies for a gaseous reaction at two different temperatures and two different activation energies. [Diagram showing Boltzmann distribution curves at temperatures $T_1$ and $T_2$ with activation energies $E_{\mathrm{A}(1)}$ and $E_{\mathrm{A}(2)}$] Which combination of temperature and activation energy will give the highest reaction rate? A $T_1$ and $E_{\mathrm{A}(1)}$ B $T_1$ and $E_{\mathrm{A}(2)}$ C $T_2$ and $E_{\mathrm{A}(2)}$ D $T_2$ and $E_{\mathrm{A}(1)}$

The reaction between sulfur dioxide and oxygen has the equation shown. $$2\mathrm{S}{\mathrm{O}}_2(\mathrm{g})+{\mathrm{O}}_2(\mathrm{g})\rightleftharpoons 2\mathrm{S}{\mathrm{O}}_3(\mathrm{g})\mathrm{\Delta }H=-197{\text{ kJ mol}}^{-1}$$ $1.0\text{ mol}$ of $\mathrm{S}{\mathrm{O}}_2$ and $1.0\text{ mol}$ of ${\mathrm{O}}_2$ are placed in a closed container and heated to a constant temperature. At this temperature, $0.8\text{ mol}$ of $\mathrm{S}{\mathrm{O}}_3$ are present in the equilibrium mixture. Which statement is correct? A The equilibrium partial pressure of $\mathrm{S}{\mathrm{O}}_2$ is greater than the equilibrium partial pressure of ${\mathrm{O}}_2$. B $K_p$ has units of $\mathrm{m}\mathrm{o}\mathrm{l}\mathrm{d}{\mathrm{m}}^{-3}$. C At a lower temperature, the equilibrium amount of $\mathrm{S}{\mathrm{O}}_3$ is lower than $0.8\text{ mol}$. D The mole fraction of $\mathrm{S}{\mathrm{O}}_3$ is less than 0.8.

‘Red lead’ is a red pigment with the formula $\mathrm{P}{\mathrm{b}}_3{\mathrm{O}}_4$. 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

Some standard enthalpy of combustion data are given.

Using these data, what is the enthalpy change of formation of methanol? A $-240{\text{ kJ mol}}^{-1}$ B $-46{\text{ kJ mol}}^{-1}$ C $46{\text{ kJ mol}}^{-1}$ D $240{\text{ kJ mol}}^{-1}$

Which row is correct?

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?

Aqueous hydrogen peroxide, ${\mathrm{H}}_2{\mathrm{O}}_2$, decomposes into water and oxygen in the presence of a suitable catalyst. $50{\text{ cm}}^3$ of a $0.50{\text{ mol dm}}^{-3}$ solution of hydrogen peroxide produced $120{\text{ cm}}^3$ of oxygen in $2.0\text{ minutes}$. The volume of gas was measured at room conditions. What is the average rate of decomposition of hydrogen peroxide during this $2.0\text{ minute}$ period? A $0.000083{\text{ mol dm}}^{-3}{\text{ s}}^{-1}$ B $0.00083{\text{ mol dm}}^{-3}{\text{ s}}^{-1}$ C $0.0017{\text{ mol dm}}^{-3}{\text{ s}}^{-1}$ D $0.10{\text{ mol dm}}^{-3}{\text{ s}}^{-1}$

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. $${\mathrm{H}}_2\mathrm{O}(\mathrm{l})\rightleftharpoons {\mathrm{H}}_2\mathrm{O}(\mathrm{g})\mathrm{\Delta }{H}_{\mathrm{b}}$$ $${\mathrm{H}}_2\mathrm{O}(\mathrm{s})\rightleftharpoons {\mathrm{H}}_2\mathrm{O}(\mathrm{l})\mathrm{\Delta }{H}_{\mathrm{m}}$$ Which statements are correct? 1 $\mathrm{\Delta }{H}_{\mathrm{b}}$ and $\mathrm{\Delta }{H}_{\mathrm{m}}$ are both negative. 2 $\mathrm{\Delta }{H}_{\mathrm{b}}$ is greater than $\mathrm{\Delta }{H}_{\mathrm{m}}$. 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

An experiment is carried out to determine the value of $x$ in hydrated lithium hydroxide, $\mathrm{L}\mathrm{i}\mathrm{O}\mathrm{H}\cdot x{\mathrm{H}}_2\mathrm{O}$. A sample of the solid is heated in a crucible over a Bunsen flame. Complete dehydration takes place; decomposition does not occur. $$\begin{array}{rl}{\displaystyle \text{mass of empty crucible / g}}& {\displaystyle =Q}\\ {\displaystyle \text{mass of crucible with }\mathrm{L}\mathrm{i}\mathrm{O}\mathrm{H}\cdot x{\mathrm{H}}_2\mathrm{O}\text{ / g}}& {\displaystyle =R}\\ {\displaystyle \text{mass of crucible and residue after heating / g}}& {\displaystyle =S}\end{array}$$ Which equation gives the correct value of $x$? A $\frac{S-R}{18}$ B $\frac{R-S}{18}$ C $\frac{23.9(R-S)}{18(S-Q)}$ D $\frac{23.9(S-R)}{18(S-Q)}$

A sample of an ideal gas occupies $240{\text{ cm}}^3$ at $37{}^{\circ }\mathrm{C}$ and $100\text{ kPa}$. How many moles of gas are present in the sample? A $9.32\times {10}^{-6}$ B $9.32\times {10}^{-3}$ C $0.0781$ D $78.1$

Under certain conditions, $\mathrm{C}\mathrm{C}{\mathrm{l}}_4$ and ${\mathrm{H}}_2\mathrm{O}$ react as shown. The activation energy for the reaction is $+62{\text{ kJ mol}}^{-1}$. $$\mathrm{C}\mathrm{C}{\mathrm{l}}_4+2{\mathrm{H}}_2\mathrm{O}\to \mathrm{C}{\mathrm{O}}_2+4\mathrm{H}\mathrm{C}\mathrm{l}\mathrm{\Delta }H=-61.5{\text{ kJ mol}}^{-1}$$ Which enthalpy profile diagram best fits this reaction? [Diagrams A, B, C, and D showing enthalpy profile curves of reaction path vs enthalpy for $\mathrm{C}\mathrm{C}{\mathrm{l}}_4+2{\mathrm{H}}_2\mathrm{O}\to \mathrm{C}{\mathrm{O}}_2+4\mathrm{H}\mathrm{C}\mathrm{l}$]

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? [Diagram showing electric field with deflected paths labelled 1, 2, 3, 4, 5]

The skeletal formulae of arginine and lysine are shown. [Skeletal formulae of arginine and lysine] Which row is correct?

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 $\mathrm{A}\mathrm{l}$ B $\mathrm{C}\mathrm{a}$ C $\mathrm{N}\mathrm{a}$ D $\mathrm{P}$

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.

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.

What is compound M? A aluminium chloride B magnesium chloride C phosphorus pentachloride D sodium chloride

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.

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?

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

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 $\mathrm{M}\mathrm{g}\mathrm{C}{\mathrm{l}}_2$ B $\mathrm{M}\mathrm{g}\mathrm{S}$ C $\mathrm{N}{\mathrm{a}}_2\mathrm{S}$ D $\mathrm{P}\mathrm{C}{\mathrm{l}}_3$

$1.0\text{ g}$ 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

Sulfur dioxide in the atmosphere can form acid rain. This occurs in two steps. 1 oxidation of $\mathrm{S}{\mathrm{O}}_2$ to $\mathrm{S}{\mathrm{O}}_3$ 2 formation of dilute ${\mathrm{H}}_2\mathrm{S}{\mathrm{O}}_4$ Which row identifies the atmospheric catalyst for step 1 and the reagent for step 2?

Which statement about the mechanism of an ${\mathrm{S}}_{\mathrm{N}}1$ 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.

The repeat unit of a polymer is shown. [Diagram showing polymer repeat unit: $-[\mathrm{C}{\mathrm{H}}_2-\mathrm{C}\mathrm{H}\mathrm{C}\mathrm{l}-\mathrm{C}{\mathrm{H}}_2-\mathrm{C}\mathrm{H}(\mathrm{O}\mathrm{H}){]}_n-$] 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

Methanoic acid, $\mathrm{H}\mathrm{C}{\mathrm{O}}_2\mathrm{H}$, 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 $\mathrm{H}\mathrm{C}{\mathrm{O}}_2\mathrm{H}$ and $\mathrm{C}{\mathrm{H}}_3\mathrm{C}{\mathrm{O}}_2\mathrm{H}$ B $\mathrm{H}\mathrm{C}{\mathrm{O}}_2\mathrm{H}$ and $\mathrm{C}{\mathrm{H}}_3\mathrm{C}{\mathrm{O}}_2\mathrm{C}{\mathrm{H}}_3$ C $\mathrm{H}\mathrm{C}{\mathrm{O}}_2\mathrm{H}$ and $\mathrm{C}{\mathrm{H}}_3\mathrm{C}{\mathrm{H}}_2\mathrm{C}\mathrm{O}\mathrm{C}{\mathrm{H}}_3$ D $\mathrm{H}\mathrm{C}{\mathrm{O}}_2\mathrm{H}$ and $\mathrm{C}{\mathrm{H}}_3\mathrm{C}{\mathrm{H}}_2\mathrm{C}\mathrm{H}\mathrm{O}$

Which row gives pentanenitrile as one product?

An ester, ${\mathrm{R}}^{\mathrm{\prime }}\mathrm{C}{\mathrm{O}}_2{\mathrm{R}}^{\mathrm{\prime }\mathrm{\prime }}$, is hydrolysed in alkaline conditions. ${\mathrm{R}}^{\mathrm{\prime }}$ and ${\mathrm{R}}^{\mathrm{\prime }\mathrm{\prime }}$ are different alkyl groups. Which row identifies the two products formed?

Which compound cannot be oxidised by acidified potassium dichromate(VI) solution but does react with sodium metal? A $(\mathrm{C}{\mathrm{H}}_3{)}_3\mathrm{C}\mathrm{O}\mathrm{H}$ B $\mathrm{C}{\mathrm{H}}_3\mathrm{C}\mathrm{O}\mathrm{C}{\mathrm{H}}_2\mathrm{C}{\mathrm{H}}_3$ C $\mathrm{C}{\mathrm{H}}_3\mathrm{C}{\mathrm{H}}_2\mathrm{C}{\mathrm{H}}_2\mathrm{C}{\mathrm{H}}_2\mathrm{O}\mathrm{H}$ D $\mathrm{C}{\mathrm{H}}_3\mathrm{C}{\mathrm{H}}_2\mathrm{C}\mathrm{H}(\mathrm{O}\mathrm{H})\mathrm{C}{\mathrm{H}}_3$

Butan-2-one reacts with alkaline ${\mathrm{I}}_2(\mathrm{a}\mathrm{q})$. 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

Four reagents are listed. 1 aqueous $\mathrm{K}\mathrm{C}\mathrm{l}$ 2 dilute $\mathrm{H}\mathrm{C}\mathrm{l}$ 3 liquid $\mathrm{S}\mathrm{O}\mathrm{C}{\mathrm{l}}_2$ 4 solid $\mathrm{P}\mathrm{C}{\mathrm{l}}_5$ 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

Four drops of 1-chlorobutane, 1-bromobutane and 1-iodobutane are put separately into three test-tubes containing $1.0{\text{ cm}}^3$ of aqueous silver nitrate at $60{}^{\circ }\mathrm{C}$. In each case, a hydrolysis reaction occurs. $${\mathrm{H}}_2\mathrm{O}(\mathrm{l})+\mathrm{R}-\mathrm{X}(\mathrm{l})+\mathrm{A}{\mathrm{g}}^{+}(\mathrm{a}\mathrm{q})\to \mathrm{R}-\mathrm{O}\mathrm{H}(\mathrm{a}\mathrm{q})+\mathrm{A}\mathrm{g}\mathrm{X}(\mathrm{s})+{\mathrm{H}}^{+}(\mathrm{a}\mathrm{q})$$ $\mathrm{R}$ represents ${\mathrm{C}}_4{\mathrm{H}}_9$ and $\mathrm{X}$ represents the halogen atom. The rate of formation of cloudiness in the test-tubes is in the order $\mathrm{R}\mathrm{C}\mathrm{l}<\mathrm{R}\mathrm{B}\mathrm{r}<\mathrm{R}\mathrm{I}$. Why is this? A The bond energy of $\mathrm{R}-\mathrm{X}$ decreases from $\mathrm{R}\mathrm{C}\mathrm{l}$ to $\mathrm{R}\mathrm{I}$. B The first ionisation energy of the halogen decreases from $\mathrm{C}\mathrm{l}$ to $\mathrm{I}$. C The solubility of $\mathrm{A}\mathrm{g}\mathrm{X}(\mathrm{s})$ decreases from $\mathrm{A}\mathrm{g}\mathrm{C}\mathrm{l}$ to $\mathrm{A}\mathrm{g}\mathrm{I}$. D The $\mathrm{R}-\mathrm{X}$ bond polarity decreases from $\mathrm{R}\mathrm{C}\mathrm{l}$ to $\mathrm{R}\mathrm{I}$.

Propanoic acid reacts with $\mathrm{L}\mathrm{i}\mathrm{A}\mathrm{l}{\mathrm{H}}_4$ 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?

Samples of the gases $\mathrm{C}{\mathrm{H}}_3\mathrm{C}\mathrm{l}$ and $\mathrm{C}{\mathrm{l}}_2$ are mixed together and irradiated with ultraviolet light. Which compound is produced by a termination step in the reaction? A $\mathrm{H}\mathrm{C}\mathrm{l}$ B $\mathrm{C}{\mathrm{H}}_2=\mathrm{C}{\mathrm{H}}_2$ C $\mathrm{C}{\mathrm{H}}_2\mathrm{C}\mathrm{l}\mathrm{C}{\mathrm{H}}_2\mathrm{C}\mathrm{l}$ D ${\mathrm{H}}_2$

Propan-1-ol, ${\mathrm{C}}_3{\mathrm{H}}_7\mathrm{O}\mathrm{H}$, 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? [Structures A: 1-bromopropane, B: 2-bromopropane, C: 1,1-dibromopropane, D: 1,2-dibromopropane]

Alkane S has molecular formula ${\mathrm{C}}_4{\mathrm{H}}_{10}$. S reacts with $\mathrm{C}{\mathrm{l}}_2(\mathrm{g})$ in the presence of sunlight to produce only two different monochloroalkanes, ${\mathrm{C}}_4{\mathrm{H}}_9\mathrm{C}\mathrm{l}$. Both of these monochloroalkanes are treated with hot ethanolic $\mathrm{K}\mathrm{O}\mathrm{H}$. They both produce the same alkene T, and no other organic products. What is produced when T is treated with hot concentrated acidified $\mathrm{K}\mathrm{M}\mathrm{n}{\mathrm{O}}_4$? A $\mathrm{C}{\mathrm{O}}_2$ and $\mathrm{C}{\mathrm{H}}_3\mathrm{C}{\mathrm{H}}_2\mathrm{C}{\mathrm{O}}_2\mathrm{H}$ B $\mathrm{C}{\mathrm{O}}_2$ and $\mathrm{C}{\mathrm{H}}_3\mathrm{C}\mathrm{O}\mathrm{C}{\mathrm{H}}_3$ C $\mathrm{H}\mathrm{C}{\mathrm{O}}_2\mathrm{H}$ and $\mathrm{C}{\mathrm{H}}_3\mathrm{C}\mathrm{O}\mathrm{C}{\mathrm{H}}_3$ D $\mathrm{C}{\mathrm{H}}_3\mathrm{C}{\mathrm{O}}_2\mathrm{H}$ only

Including structural isomers and stereoisomers, how many isomers are there of ${\mathrm{C}}_2{\mathrm{H}}_2\mathrm{B}{\mathrm{r}}_2$? A 2 B 3 C 4 D 5

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

The mass spectrum of $\mathrm{C}{\mathrm{H}}_3\mathrm{C}\mathrm{l}$ shows a molecular ion peak, ${\mathrm{M}}^{+}$, at the $m\mathrm{/}e$ value of 50 with a relative abundance of $18.0\mathrm{\%}$. Other peaks are present in the mass spectrum. What is seen in the mass spectrum at the $m\mathrm{/}e$ value of 52? A a peak with relative abundance of $4.5\mathrm{\%}$ B a peak with relative abundance of $6.0\mathrm{\%}$ C a peak with relative abundance of $18.0\mathrm{\%}$ D a peak with relative abundance of $54.0\mathrm{\%}$