A Level Chemistry 9701 Paper 22, May/June 2026

State the total number of electrons that occupy the 2p sub-shell in an oxygen atom.

Name the orbital that contains the highest energy electron in an oxygen atom. Draw the shape of this orbital. name ................................................................................................................................. shape

Lithium reacts with oxygen to produce lithium oxide, $\mathrm{L}{\mathrm{i}}_2\mathrm{O}$. $\mathrm{L}{\mathrm{i}}_2\mathrm{O}$ is a white solid with a melting point over $1400{}^{\circ }\mathrm{C}$. Draw a dot-and-cross diagram to show the arrangement of all the electrons in $\mathrm{L}{\mathrm{i}}_2\mathrm{O}$.

$\mathrm{L}{\mathrm{i}}_2\mathrm{O}$ reacts with water to produce a solution with $\mathrm{p}\mathrm{H}$ greater than 10. State the name of a Period 3 oxide that behaves in the same way as $\mathrm{L}{\mathrm{i}}_2\mathrm{O}$ when added to water.

Construct an equation for the reaction of $\mathrm{L}{\mathrm{i}}_2\mathrm{O}$ with water.

Identify all the Period 3 chlorides that are solid at room temperature and that react with water to produce an acidic solution.

$\mathrm{L}\mathrm{i}\mathrm{N}{\mathrm{O}}_3$ decomposes on heating to produce $\mathrm{L}{\mathrm{i}}_2\mathrm{O}$, ${\mathrm{O}}_2$ and a brown gas. Identify the brown gas.

Ammonia is made in the Haber process. $${\mathrm{N}}_2(\mathrm{g})+3{\mathrm{H}}_2(\mathrm{g})\rightleftharpoons 2\mathrm{N}{\mathrm{H}}_3(\mathrm{g})\mathrm{\Delta }H=-92.4\mathrm{k}\mathrm{J}\mathrm{m}\mathrm{o}{\mathrm{l}}^{-1}$$ A temperature of $400\text{–}450{}^{\circ }\mathrm{C}$ is used in the Haber process. State two other conditions used in the Haber process. 1 ........................................................................................................................................ 2 ........................................................................................................................................

Describe how the initial rate of the forward reaction changes, if at all, when a temperature greater than $450{}^{\circ }\mathrm{C}$ is used. Explain your answer. Assume all other variables remain constant. change in initial rate .......................................................................................................... explanation ........................................................................................................................ ........................................................................................................................................... ...........................................................................................................................................

Protons, neutrons and electrons are released with the same velocity from a source. Figure 2.1 shows the movement of two of these types of particle when they travel between oppositely charged plates. Name each type of particle that produces the deflection shown by curves x and y. curve x = ............................................................... curve y = ...............................................................

Suggest why the particles producing curve y are deflected less than the particles producing curve x.

A student considers the information in Table 2.1 and proposes hypothesis 1. hypothesis 1 'Atoms with a higher nuclear charge are always larger.' Identify a pair of atoms from Table 2.1 that supports hypothesis 1.

Identify a pair of atoms from Table 2.1 that shows hypothesis 1 is false.

Explain why atom A is smaller than atom C.

Write an equation for reaction 1.

Explain why reaction 1 is described as a Brønsted–Lowry acid–base reaction.

Identify the formula of each species responsible for the observations in reaction 2. steamy fumes ............................................................... brown vapour ............................................................... pungent smelling gas ...............................................................

Explain why reaction 2 produces brown vapour.

Explain why a gas with a pungent smell is not produced in reaction 1 but is produced in reaction 2.

Figure 4.1 shows two reactions of compound D. D reacts with a single reagent, G, to produce compound E. Identify reagent G.

D is heated with $\mathrm{A}{\mathrm{l}}_2{\mathrm{O}}_3$ to produce organic compound F. Identify the role of $\mathrm{A}{\mathrm{l}}_2{\mathrm{O}}_3$ in this reaction.

Draw the structure of F in Figure 4.1.

The structure of compound X is shown in Figure 4.2. The molecular formula of X is ${\mathrm{C}}_5{\mathrm{H}}_{12}{\mathrm{O}}_4$. Complete oxidation of $0.255\mathrm{g}$ of X occurs when it reacts with exactly $10.0\mathrm{c}{\mathrm{m}}^3$ of $0.500\mathrm{m}\mathrm{o}\mathrm{l}\mathrm{d}{\mathrm{m}}^{-3}$ acidified ${\mathrm{K}}_2\mathrm{C}{\mathrm{r}}_2{\mathrm{O}}_7(\mathrm{a}\mathrm{q})$. Describe the colour change in this reaction. colour of mixture at start of the reaction ............................................................................ colour of mixture after the reaction ....................................................................................

Calculate the amount, in mol, of ${\mathrm{K}}_2\mathrm{C}{\mathrm{r}}_2{\mathrm{O}}_7(\mathrm{a}\mathrm{q})$ used in the reaction. amount = .................................................. mol

Calculate the amount, in mol, of X present in the $0.255\mathrm{g}$ sample. amount = .................................................. mol

Compounds X and W are a pair of structural isomers. $0.0012\mathrm{m}\mathrm{o}\mathrm{l}$ of W is completely oxidised when it is heated under reflux with exactly $0.0020\mathrm{m}\mathrm{o}\mathrm{l}$ of acidified ${\mathrm{K}}_2\mathrm{C}{\mathrm{r}}_2{\mathrm{O}}_7(\mathrm{a}\mathrm{q})$ to produce compound Z. Complete the equation for this reaction. $$3{\mathrm{C}}_5{\mathrm{H}}_{12}{\mathrm{O}}_4+\mathrm{.}\mathrm{.}\mathrm{.}\mathrm{.}\mathrm{.}\mathrm{C}{\mathrm{r}}_2{\mathrm{O}}_7^{2-}+\mathrm{.}\mathrm{.}\mathrm{.}\mathrm{.}\mathrm{.}{\mathrm{H}}^{+}\to 3{\mathrm{C}}_5{\mathrm{H}}_6{\mathrm{O}}_6+\mathrm{.}\mathrm{.}\mathrm{.}\mathrm{.}\mathrm{.}\mathrm{C}{\mathrm{r}}^{3+}+\mathrm{.}\mathrm{.}\mathrm{.}\mathrm{.}\mathrm{.}{\mathrm{H}}_2\mathrm{O}$$

Each molecule of W contains four hydroxyl groups. Only two of these are primary hydroxyl groups. Table 4.1 shows the observations when separate samples of Z are added to each reagent. Use the information in 4(c) to suggest the structure of W.

Complete Table 5.1.

The mechanism for the reaction of hexane with $\mathrm{C}{\mathrm{l}}_2(\mathrm{g})$ involves three stages. stage 1 initiation stage 2 propagation stage 3 termination In stage 1 and 2, free radicals are produced. Describe what is meant by free radical.

Name the type of bond breaking that occurs to produce the free radical $\bullet \mathrm{C}\mathrm{l}$ from $\mathrm{C}{\mathrm{l}}_2$.

Suggest a reaction sequence of two propagation reactions that result in $\mathrm{C}{\mathrm{H}}_3(\mathrm{C}{\mathrm{H}}_2{)}_4\mathrm{C}{\mathrm{H}}_3$ forming $\mathrm{C}{\mathrm{H}}_3(\mathrm{C}{\mathrm{H}}_2{)}_3\mathrm{C}\mathrm{H}\mathrm{C}\mathrm{l}\mathrm{C}{\mathrm{H}}_3$. propagation reaction 1 $\mathrm{C}{\mathrm{H}}_3(\mathrm{C}{\mathrm{H}}_2{)}_4\mathrm{C}{\mathrm{H}}_3$ ...................................... .................................................................. propagation reaction 2 ............................................................... $\mathrm{C}{\mathrm{H}}_3(\mathrm{C}{\mathrm{H}}_2{)}_3\mathrm{C}\mathrm{H}\mathrm{C}\mathrm{l}\mathrm{C}{\mathrm{H}}_3$ .................................

Suggest a reaction sequence of one propagation reaction followed by a termination reaction that results in $\mathrm{C}{\mathrm{H}}_3(\mathrm{C}{\mathrm{H}}_2{)}_4\mathrm{C}{\mathrm{H}}_3$ forming $\mathrm{C}{\mathrm{H}}_3(\mathrm{C}{\mathrm{H}}_2{)}_{10}\mathrm{C}{\mathrm{H}}_3$. propagation reaction $\mathrm{C}{\mathrm{H}}_3(\mathrm{C}{\mathrm{H}}_2{)}_4\mathrm{C}{\mathrm{H}}_3$ ...................................... .............................................................. termination reaction ................................................................................... $\mathrm{C}{\mathrm{H}}_3(\mathrm{C}{\mathrm{H}}_2{)}_{10}\mathrm{C}{\mathrm{H}}_3$

The proportion of each product varies depending on the type of free radical intermediate that is produced. Use Table 5.2 to suggest which factor determines the increased stability of free radicals from primary to secondary to tertiary.

Figure 6.1 shows the structure of compound P. Draw the structure of the stereoisomer of P.

Explain why P shows stereoisomerism.

P reacts to produce compound Q. Identify the reagent and conditions required to convert P to Q. reagent .............................................................................................................................. conditions ..........................................................................................................................

Complete Figure 6.3 to show the pair of stereoisomers of Q.

An unlabelled sample contains one of compounds P, R or S. The mass spectrum of the sample is shown in Figure 6.5. Identify the one peak on Figure 6.5 which confirms that the sample is P. Explain your reasoning.

Suggest the structural formulae of the fragments responsible for the peaks at $m\mathrm{/}e=45$ and $m\mathrm{/}e=99$. structural formula of fragment at $m\mathrm{/}e=45$ ....................................................................... structural formula of fragment at $m\mathrm{/}e=99$ .......................................................................

Suggest one reagent that is used to distinguish between samples of R and S. Include appropriate observations.