A Level Chemistry 9701 Paper 22, May/June 2025

Diamond and graphite are both crystalline solids made from carbon atoms. Graphite conducts electricity. Diamond does not conduct electricity. Name the type of lattice structure present in the crystalline solids diamond and graphite.

Explain how graphite conducts electricity.

Explain why diamond does not conduct electricity.

Separate samples of phosphorus(V) chloride and silicon(IV) chloride are each added to an excess of cold water. Write an equation for each reaction.

Describe the appearance of phosphorus(V) chloride and silicon(IV) chloride at room temperature. phosphorus(V) chloride ..................................................................................................... silicon(IV) chloride ............................................................................................................

Compare the appearance of the mixtures produced when each reaction is complete.

Some oxides are amphoteric. Describe what is meant by amphoteric.

Identify the formula of a Period 3 oxide that is amphoteric.

The melting points of different oxides are shown in Table 1.1. Table 1.1

Complete Table 1.1 by identifying the strongest force of attraction in each oxide that is broken during melting. Use the abbreviations below. i.d. = instantaneous dipole–induced dipole p.d. = permanent dipole–permanent dipole H = hydrogen bond C = covalent bond I = ionic bond

A student suggests the following hypothesis. The stronger the covalent bond between atoms in non-metal oxides, the higher the melting point. Use Table 1.1 to deduce if this hypothesis is true or false or if there is not enough information to make a conclusion. Explain your answer.

Define relative atomic mass.

Table 2.1 shows the abundances of two of the isotopes present in the sample of iron. Table 2.1

Use Table 2.1 to calculate the relative isotopic mass of the third isotope of iron in the sample. Show your working. relative isotopic mass = ..............................

Deduce the number of pairs of electrons in the 3d sub-shell in an iron(II) ion.

Sketch the shape of the lowest energy orbital in the shell with principal quantum number $n=2$.

Complete Table 2.2 to show information about particles in one ion of ${}^{56}{\text{Fe}}^{3+}$. Table 2.2

The atomic radius of iron is $1.26\times {10}^{-10}\text{m}$. Suggest the change to the radius, if any, after an iron atom reacts to produce an ${\text{Fe}}^{3+}$ ion. Explain your answer.

${\text{C}}_3{\text{H}}_6$ reacts with $\text{HBr}(\text{g})$ in an addition reaction. Define addition reaction.

Complete Fig. 3.1 to show the mechanism for the addition reaction between ${\text{C}}_3{\text{H}}_6$ and $\text{HBr}$ to produce 2-bromopropane. Include charges, dipoles, lone pairs of electrons and curly arrows, as appropriate. Fig. 3.1

Explain why the major product of this reaction is 2-bromopropane rather than 1-bromopropane.

${\text{H}}_2(\text{g})$ and nickel are added to alkene $\mathbf{X}$. Fig. 3.2 shows how the concentration of $\mathbf{X}$ changes with time. Fig. 3.2 Use Fig. 3.2 to identify the limiting reagent in this reaction. Explain your answer.

Use Fig. 3.2 to describe how the gradient changes as the reaction proceeds. State what this shows about the rate during this reaction.

Hydrocarbon $\mathbf{Y}$ contains two $\text{C=C}$ groups. There are no other functional groups present. $\mathbf{Y}$ reacts with an excess of ${\text{H}}_2(\text{g})$ to produce hexane, ${\text{C}}_6{\text{H}}_{14}$. Table 3.1

Use Table 3.1 to calculate the enthalpy change per mole of ${\text{C}}_6{\text{H}}_{14}$ produced in this reaction. enthalpy change = .............................. $\text{kJ}{\text{mol}}^{-1}$

Hydrocarbon $\mathbf{Y}$ reacts with ${\text{H}}_2(\text{g})$. Fig. 3.3 shows the distribution of energies of ${\text{H}}_2(\text{g})$ at temperature $T$. Area A represents the number of molecules with energy greater than or equal to the activation energy, $E_{\text{A}}$, at temperature $T$. Fig. 3.3 Annotate Fig. 3.3 to show the effect of adding nickel to $\mathbf{Y}$ and ${\text{H}}_2(\text{g})$ at temperature $T$.

Area B (not labelled on Fig. 3.3) represents the number of molecules with energy greater than or equal to the activation energy when nickel is added at temperature $T$. State the difference, if any, between areas A and B. Explain the significance of your answer on the rate of hydrogenation of $\mathbf{Y}$. Give your answer in terms of collisions.

Alkene $\mathbf{Z}$ contains two $\text{C=C}$ bonds. $\mathbf{Z}$ reacts with an excess of hot concentrated acidified ${\text{KMnO}}_4$ to produce only ${\text{CH}}_3{\text{COCH}}_3$, ${\text{HOOCCH}}_2\text{COOH}$, ${\text{CO}}_2$ and ${\text{H}}_2\text{O}$. Suggest the structure of $\mathbf{Z}$.

Propanoic acid, ${\text{CH}}_3{\text{CH}}_2\text{COOH}$, reacts with reducing agent $\mathbf{Q}$ to produce propan-1-ol, ${\text{CH}}_3{\text{CH}}_2{\text{CH}}_2\text{OH}$. Suggest the formula of reducing agent $\mathbf{Q}$.

Complete the equation to show the reduction of propanoic acid to propan-1-ol. Use [H] to represent one atom of hydrogen from $\mathbf{Q}$. ......${\text{CH}}_3{\text{CH}}_2\text{COOH}$ + ......[H] $\to$ ...................................................................................

Propan-1-ol is converted to compound $\mathbf{T}$ in a three-step synthesis. In step 1, ${\text{SOCl}}_2$ is added to propan-1-ol to produce compound $\mathbf{E}$. In step 2, $\mathbf{E}$ reacts with a suitable reagent to produce butanenitrile. In step 3, butanenitrile is heated with $\text{NaOH}(\text{aq})$. Name the type of reaction that occurs in step 1.

Identify the reagent and conditions required in step 2.

Construct an equation to describe the reaction of butanenitrile with $\text{NaOH}(\text{aq})$ in step 3.

Name the type of reaction that occurs in step 3.

Compounds $\mathbf{A}$, $\mathbf{B}$ and $\mathbf{C}$ belong to the alcohol homologous series. Each molecule of $\mathbf{A}$, $\mathbf{B}$ and $\mathbf{C}$ contains four saturated carbon atoms. Identify the type of hybridisation shown in the saturated carbon atoms of all alcohols.

Identify the gas produced when $\text{Na}(\text{s})$ is added to separate samples of each alcohol.

Describe the role of $\text{Na}(\text{s})$ when it reacts with alcohols.

Table 4.1 shows the results of two tests on separate samples of $\mathbf{A}$, $\mathbf{B}$ and $\mathbf{C}$. Table 4.1

Deduce the structure of $\mathbf{A}$.

Deduce a possible name for $\mathbf{B}$.

Deduce the identity of $\mathbf{C}$.

Deduce the empirical formula of vitamin C.

The mass of vitamin C present in $150.0\text{g}$ of lemon is found in an experiment. stage 1 All the vitamin C in $150.0\text{g}$ of lemon is extracted and dissolved in water to make $100.0{\text{cm}}^3$ of solution $\mathbf{L}$. stage 2 A $25.0{\text{cm}}^3$ sample of solution $\mathbf{L}$ is titrated with $5.00\times {10}^{-3}\text{mol}{\text{dm}}^{-3}{\text{I}}_2(\text{aq})$. Fig. 5.2 Exactly $36.65{\text{cm}}^3$ of ${\text{I}}_2(\text{aq})$ reacts with the $25.0{\text{cm}}^3$ sample of solution $\mathbf{L}$. [$M_{\text{r}}$: vitamin C, 176] Calculate the amount, in mol, of ${\text{I}}_2(\text{aq})$ added in the titration. amount of ${\text{I}}_2(\text{aq})$ = .............................. mol

Use your answer to (b)(i) to calculate the percentage by mass of vitamin C present in $150.0\text{g}$ of lemon. (If you were unable to calculate a value for the amount of ${\text{I}}_2(\text{aq})$ in (b)(i), use the value $7.65\times {10}^{-4}\text{mol}$. This is not the correct value.) percentage by mass = ..............................%

The progress of the reaction of vitamin C with ${\text{I}}_2(\text{aq})$ to produce $\mathbf{M}$ is monitored using infrared spectroscopy. Table 5.1 indicates the presence of some absorptions in the infrared spectrum of vitamin C. Complete Table 5.1 to predict which of these absorptions, if any, are present in the infrared spectrum of $\mathbf{M}$. Table 5.1

Table 5.2