A Level Chemistry 9701 Paper 22, Oct/Nov 2025

Mn is usually found as a single isotope, manganese-55. Determine the number of protons, neutrons and electrons in an atom of manganese-55. number of protons .......................... neutrons .......................... electrons ..........................

Define isotopes.

A sample of manganese from the Moon is found to contain manganese-53 in addition to manganese-55. State the two pieces of information needed to determine the relative atomic mass, $A_r$, of manganese in this sample. 1 ........................................................................................................................................ 2 ........................................................................................................................................

The shorthand electronic configuration of manganese is $[extAr]ext{3d}^{5}ext{4s}^2$. Complete the full electronic configuration of manganese. ......................................................................... ${\text{3d}}^5{\text{ 4s}}^2$

Deduce the total number of unpaired electrons in an atom of manganese.

Manganese(IV) oxide reacts with methanal, ${\text{CH}}_2\text{O}$, in acidic conditions to produce carbon dioxide. The movement of electrons to or from relevant species is shown in the following half-equations. half-equation 1 ${\text{CH}}_2\text{O}+{\text{H}}_2\text{O}\to {\text{CO}}_2+4{\text{H}}^{+}+4{\text{e}}^{-}$ half-equation 2 ${\text{MnO}}_2+4{\text{H}}^{+}+2{\text{e}}^{-}\to {\text{Mn}}^{2+}+2{\text{H}}_2\text{O}$ Identify the species that is reduced in half-equation 2. Explain your answer.

The oxidation state of carbon in methanal is 0. Calculate the oxidation state of carbon in carbon dioxide.

Construct the ionic equation for the reaction of manganese(IV) oxide with methanal in acidic conditions.

Explain why the elements Na to Al are good electrical conductors.

Explain why the elements P, S and Cl do not conduct electricity.

Fig. 2.1 shows the variation in melting point of the Period 3 elements Si to Cl. The Period 3 elements Si to Cl are all non-metals. Explain why there is a large difference between the melting point of Si and the melting points of P, S and Cl.

Table 2.1 gives some information about some Period 3 chlorides. Row B refers to the pH of the solution that forms when the Period 3 chloride is added to water. Table 2.1 Complete Table 2.1. You may use the following abbreviations. I = ionic, C = covalent, M = metallic G = giant, S = simple

Write an equation for the formation of ${\text{AlCl}}_3$ from its elements.

Write an equation for the formation of ${\text{H}}_3{\text{PO}}_4$ from ${\text{PCl}}_5$.

${\text{S}}_2{\text{Cl}}_2(\text{l})$ reacts with ${\text{Cl}}_2(\text{g})$ in a reversible reaction to form ${\text{SCl}}_2(\text{l})$. Under certain conditions, a dynamic equilibrium is established. $${\text{S}}_2{\text{Cl}}_2(\text{l})+{\text{Cl}}_2(\text{g})\rightleftharpoons 2{\text{SCl}}_2(\text{l})\mathrm{\Delta }H=-41{\text{ kJ mol}}^{-1}$$ State what is meant by dynamic equilibrium.

Identify the condition necessary to establish dynamic equilibrium.

${\text{S}}_2{\text{Cl}}_2(\text{l})$ is yellow and ${\text{SCl}}_2(\text{l})$ is red. $${\text{S}}_2{\text{Cl}}_2(\text{l})+{\text{Cl}}_2(\text{g})\rightleftharpoons 2{\text{SCl}}_2(\text{l})\mathrm{\Delta }H=-41{\text{ kJ mol}}^{-1}$$ State what is observed when the following changes are made to an equilibrium mixture of ${\text{S}}_2{\text{Cl}}_2(\text{l})$ and ${\text{SCl}}_2(\text{l})$. Explain your answers. • The equilibrium mixture is warmed gently. observation ................................................................................................................ explanation ................................................................................................................ .................................................................................................................................... .................................................................................................................................... • The overall pressure of the equilibrium mixture is increased. observation ................................................................................................................ explanation ................................................................................................................ .................................................................................................................................... ....................................................................................................................................

Aqueous ${\text{MgCl}}_2$ reacts with aqueous ${\text{Na}}_2{\text{CO}}_3$ to form a white precipitate. Upon heating, the white precipitate undergoes thermal decomposition. Construct an equation to show the reaction of aqueous ${\text{MgCl}}_2$ with aqueous ${\text{Na}}_2{\text{CO}}_3$. Use state symbols in your equation.

Identify the products of the thermal decomposition of the white precipitate.

State the trend in thermal stability of the Group 2 carbonates down the group.

Define homologous series.

Give two reasons to explain the general unreactivity of alkanes. 1 ................................................................................................................................................ 2 ................................................................................................................................................

Alkanes with low relative molecular mass, $M_r$, are more useful than those found in heavier crude oil fractions. Name the process that is used to obtain alkanes with low $M_r$ from heavier crude oil fractions.

Hexane, ${\text{C}}_6{\text{H}}_{14}$, has four structural isomers. Fig. 3.1 shows hexane and two of its structural isomers. Complete Fig. 3.1 by drawing structures for C and D, the other two structural isomers of hexane.

A, B and hexane have different boiling points. Arrange A, B and hexane in order of increasing boiling point. Explain your answer. lowest .................................... < .................................... < .................................... highest ........................................................................................................................................... ........................................................................................................................................... ...........................................................................................................................................

Hexane can be converted into compounds E and F at high temperature and pressure. Fig. 3.2 shows the reaction scheme involving hexane, E and F. Identify a suitable reagent for reaction 3.

Use the data in Fig. 3.2 and in Table 3.1 to calculate the enthalpy change of reaction 2, $\mathrm{\Delta }{H}_2$. Table 3.1 $\mathrm{\Delta }{H}_2={\text{........................................... kJ mol}}^{-1}$

Write an equation for the complete combustion of hexane.

Reaction 1 in Fig. 4.1 takes place in the presence of sunlight. $${\text{C}}_3{\text{H}}_8+{\text{Cl}}_2\to {\text{CH}}_3{\text{CH}}_2{\text{CH}}_2\text{Cl}+\text{HCl}$$ The reaction takes place via initiation, propagation and termination steps. Name the mechanism shown by reaction 1.

Complete the mechanism for reaction 1. Construct equations to describe the steps of the mechanism. initiation ${\text{Cl}}_2\to 2{\text{Cl}}^{\bullet }$ propagation 1 .................................................................................................................... propagation 2 .................................................................................................................... termination ............................................................................................ $\to {\text{CH}}_3{\text{CH}}_2{\text{CH}}_2\text{Cl}$

Reaction 1 is initiated by the bond fission of ${\text{Cl}}_2$. State the type of bond fission shown in the initiation step.

Compound Q is a by-product of reaction 1. Name Q.

The molecular formula of Q is ${\text{C}}_3{\text{H}}_6{\text{Cl}}_2$. Identify the types of structural isomerism and stereoisomerism that a molecule with molecular formula ${\text{C}}_3{\text{H}}_6{\text{Cl}}_2$ can show. type of structural isomerism .............................................................................................. type of stereoisomerism ....................................................................................................

State the reagent and solvent required for reaction 2.

Reaction 3 takes place when ${\text{CH}}_3{\text{CH}}_2{\text{CH}}_2\text{OH}$ is heated under reflux with acidified potassium dichromate(VI) solution. State the colour change that takes place in the reaction mixture.

Construct an equation to represent reaction 3. Use [O] to represent an atom of oxygen from the oxidising agent.

${\text{CH}}_3{\text{CH}}_2\text{COOH}$ reacts with an unsaturated alcohol R to form unsaturated ester S. State the type of reaction that forms S.

The infrared spectrum of S is shown in Fig. 4.2. Three absorptions in the infrared spectrum in Fig. 4.2 confirm that S is an ester and is unsaturated. • Write 1, 2 or 3 on Fig. 4.2 against each of these three absorptions. • Complete Table 4.1 to show which bond is responsible for each absorption that you have identified in Fig. 4.2. Table 4.1

The mass spectrum of S shows the following peaks. Table 4.3 Use Table 4.3 to calculate the number of carbon atoms in S. number of carbon atoms in S = ...................................................................................