A Level Chemistry 9701 Paper 12, May/June 2023

When chlorine gas is analysed in a mass spectrometer ${}^{35}{\text{Cl}}^{+}$ ions are detected. Which row is correct?

Which species is a free radical? A $\text{He}$ B ${\text{Be}}^{-}$ C ${\text{O}}^{2-}$ D $\text{Zn}$

Which statement is correct? A The first ionisation energy of chlorine is more than the first ionisation energy of argon. B The second ionisation energy of calcium is more than the second ionisation energy of magnesium. C The second ionisation energy of sulfur is equal to the first ionisation energy of phosphorus. D The eighth ionisation energy of chlorine is more than the first ionisation energy of neon.

If 1 mole of hexane combusts in an excess of oxygen, how many moles of products are formed? A 11 B 12 C 13 D 14

Separate samples, each of mass $1.0\text{ g}$, of the compounds listed are treated with an excess of dilute acid. Which compound releases the largest amount of ${\text{CO}}_2$? A $1.0\text{ g }{\text{CaCO}}_3$ B $1.0\text{ g }{\text{Li}}_2{\text{CO}}_3$ C $1.0\text{ g }{\text{MgCO}}_3$ D $1.0\text{ g }{\text{Na}}_2{\text{CO}}_3$

Which statement about the $\text{Cl}-\text{N}=\text{O}$ molecule is correct? A Each molecule contains one $\sigma$ and two $\pi$ bonds. B It is a non-polar molecule. C It is a linear molecule. D The nitrogen atom is ${\text{sp}}^2$ hybridised.

Which row is correct?

The volume of a vessel is $1.20\times {10}^{-3}{\text{ m}}^3$. It contains pure argon at a pressure of $1.00\times {10}^5\text{ Pa}$, and at a temperature of $25.0{}^{\circ }\text{C}$. Under these conditions it can be assumed that argon behaves as an ideal gas. Which mass of argon does it contain? A $0.0485\text{ g}$ B $1.93\text{ g}$ C $10.4\text{ g}$ D $23.0\text{ g}$

A student mixed $25.0{\text{ cm}}^3$ of $4.00{\text{ mol dm}}^{-3}$ hydrochloric acid with an equal volume of $4.00{\text{ mol dm}}^{-3}$ sodium hydroxide. The initial temperature of both solutions was $15.0{}^{\circ }\text{C}$. The maximum temperature recorded was $30.0{}^{\circ }\text{C}$. The heat capacity of the final solution can be assumed to be $4.18{\text{ J K}}^{-1}{\text{ g}}^{-1}$ and the density of this solution can be assumed to be $1.00{\text{ g cm}}^{-3}$. Using these results, what is the enthalpy change of neutralisation of hydrochloric acid? A $-62.7{\text{ kJ mol}}^{-1}$ B $-31.4{\text{ kJ mol}}^{-1}$ C $-15.7{\text{ kJ mol}}^{-1}$ D $-3.14{\text{ kJ mol}}^{-1}$

Nitrogen monoxide is rapidly oxidised to nitrogen dioxide. $$2\text{NO}(\text{g})+{\text{O}}_2(\text{g})\to 2{\text{NO}}_2(\text{g})$$ Nitrogen dioxide can then dimerise to form dinitrogen tetroxide. $$2{\text{NO}}_2(\text{g})\to {\text{N}}_2{\text{O}}_4(\text{g})\mathrm{\Delta }{H}^{\ominus }=-58{\text{ kJ mol}}^{-1}$$ $$\mathrm{\Delta }{H}_{\text{f}}^{\ominus }\text{NO}=+91{\text{ kJ mol}}^{-1}\text{ and }\mathrm{\Delta }{H}_{\text{f}}^{\ominus }{\text{NO}}_2=+34{\text{ kJ mol}}^{-1}$$ What is the value of the standard enthalpy change for the reaction shown? $$2\text{NO}(\text{g})+{\text{O}}_2(\text{g})\to {\text{N}}_2{\text{O}}_4(\text{g})$$ A $+56{\text{ kJ mol}}^{-1}$ B $-1{\text{ kJ mol}}^{-1}$ C $-115{\text{ kJ mol}}^{-1}$ D $-172{\text{ kJ mol}}^{-1}$

${\text{LiAlH}}_4$ contains ${\text{AlH}}_4^{-}$ ions in which aluminium has an oxidation state of $+3$. ${\text{LiAlH}}_4$ reacts with water, as shown. $${\text{LiAlH}}_4+4{\text{H}}_2\text{O}\to 4{\text{H}}_2+\text{LiOH}+{\text{Al(OH)}}_3$$ In this reaction, each of the four water molecules produces one hydroxide ion. It does this by losing one ${\text{H}}^{+}$ ion, which reacts with the ${\text{LiAlH}}_4$. Which changes in oxidation number occur in this reaction? A $\text{Al}$ increases by 1 and $\text{H}$ decreases by 1. B $\text{H}$ decreases by 2 and also increases by 1. C $\text{H}$ increases by 1 and also decreases by 1. D $\text{O}$ decreases by 1 and $\text{H}$ increases by 1.

The vanadium salt, ${\text{VOSO}}_4$, is soluble in water and reacts readily with powdered manganese in dilute sulfuric acid. The equation for the reaction is shown. $$\text{Mn(s)}+2{\text{VOSO}}_4(\text{aq})+2{\text{H}}_2{\text{SO}}_4(\text{aq})\to {\text{V}}_2({\text{SO}}_4{)}_3(\text{aq})+{\text{MnSO}}_4(\text{aq})+2{\text{H}}_2\text{O(l)}$$ Which statement about this reaction is correct? A Hydrogen is oxidised in the reaction. B Manganese is the reducing agent in this reaction. C Sulfuric acid is the oxidising agent in this reaction. D The oxidation state of the vanadium changes from $+5$ to $+3$.

In which equilibrium will an increase in pressure at constant temperature increase the yield of the products on the right-hand side of the equation? A ${\text{CaCO}}_3(\text{s})\rightleftharpoons \text{CaO(s)}+{\text{CO}}_2(\text{g})$ B $4\text{HCl(g)}+{\text{O}}_2(\text{g})\rightleftharpoons 2{\text{H}}_2\text{O(g)}+2{\text{Cl}}_2(\text{g})$ C $2\text{HI(g)}\rightleftharpoons {\text{H}}_2(\text{g})+{\text{I}}_2(\text{g})$ D $3\text{Fe(s)}+4{\text{H}}_2\text{O(g)}\rightleftharpoons {\text{Fe}}_3{\text{O}}_4(\text{s})+4{\text{H}}_2(\text{g})$

Hydrogen iodide is added to an evacuated reaction vessel. The vessel is sealed and warmed. A decomposition reaction occurs. Hydrogen and iodine are formed. Some hydrogen iodide remains. When equilibrium is established, the total pressure is $1.20\times {10}^5\text{ Pa}$. The partial pressure of hydrogen is $4.00\times {10}^3\text{ Pa}$. Hydrogen iodide, hydrogen and iodine are all gaseous under the conditions used. What is the value of $K_p$ for the equilibrium at this temperature, assuming the decomposition is the forward reaction? A $1.19\times {10}^{-3}$ B $1.28\times {10}^{-3}$ C $1.38\times {10}^{-3}$ D $1.43\times {10}^{-3}$

The equations for two reactions are shown. $$\text{reaction X}2\text{NOBr}\to 2\text{NO}+{\text{Br}}_2$$ $$\text{reaction Y}2\text{NOCl}\to 2\text{NO}+{\text{Cl}}_2$$ The two reactions have similar reaction mechanisms. The initial rate of reaction X is greater than that of reaction Y when measured under identical conditions of temperature, pressure and reactant concentration. Which statements explain this difference? 1 The activation energy for reaction X is less than that of reaction Y. 2 The $\text{Br}-\text{Br}$ bond is weaker than the $\text{Cl}-\text{Cl}$ bond. 3 A higher frequency of collisions between molecules of $\text{NOBr}$ occur than between molecules of $\text{NOCl}$. A 1 and 2 B 2 and 3 C 1 only D 3 only

The diagram shows the Boltzmann distribution of energies in a gas. The gas can take part in a reaction with an activation energy, $E_{\text{a}}$. The gas is maintained at a constant temperature. Which statement is correct? A If a catalyst is added, peak P will be lower and $E_{\text{a}}$ will move to the left. B If a catalyst is added, peak P will be lower and $E_{\text{a}}$ will move to the right. C If a catalyst is added, peak P will be the same and $E_{\text{a}}$ will move to the left. D If a catalyst is added, peak P will be the same and $E_{\text{a}}$ will move to the right.

L, M and N are three different elements from Period 3 of the Periodic Table. L is the element whose atoms have three unpaired electrons in its 3p sub-shell. M is the element with the highest electrical conductivity in the period. N is the element with the highest melting point in the period. Which statement about element L is correct? A L has a higher atomic number than M and a lower atomic number than N. B L has a lower atomic number than M and a higher atomic number than N. C L has a lower atomic number than both M and N. D L has a higher atomic number than both M and N.

In reactions 1 and 2, X represents an element in Period 3. In each reaction, X is forming a product where X is in its highest oxidation state. $$\text{reaction 1}\text{chlorine}+\text{element X}\to {\text{X}}_y{\text{Cl}}_z$$ $$\text{reaction 2}\text{oxygen}+\text{element X}\to {\text{X}}_p{\text{O}}_q$$ Which ratios show a steady increase from sodium to phosphorus? A neither $z:y$ nor $q:p$ B $z:y$ only C $q:p$ only D both $z:y$ and $q:p$

Sodium, magnesium, aluminium, silicon and phosphorus are all elements in Period 3 of the Periodic Table. Three statements about the oxides and chlorides of these elements are given. 1 The ionically bonded oxides all react with dilute hydrochloric acid. 2 All metal chlorides produce neutral solutions when added to water. 3 The two most electronegative elements both form covalently bonded chlorides. Which statements are correct? A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only

The table compares calcium with barium and calcium carbonate with barium carbonate. Which row is correct?

Solutions P and Q each contain a different Group 2 ion at the same concentration. One contains ${\text{Mg}}^{2+}$ and the other contains ${\text{Ba}}^{2+}$. Tests are carried out on separate $5{\text{ cm}}^3$ samples of P and Q. test 1: add $1{\text{ cm}}^3$ of $0.1{\text{ mol dm}}^{-3}{\text{ Na}}_2{\text{SO}}_4(\text{aq})$ test 2: add $1{\text{ cm}}^3$ of $0.1{\text{ mol dm}}^{-3}\text{ NaOH}(\text{aq})$ What are the results of these tests?

J dissolves in water to give an aqueous solution K. K gives a dense white precipitate when aqueous silver nitrate is added. When heated with aqueous potassium hydroxide, K gives off a gas that turns moist universal indicator paper blue. What is J? A ammonium chloride B ammonium sulfate C sodium chloride D sodium hydroxide

Ammonium sulfate, $({\text{NH}}_4{)}_2{\text{SO}}_4$, and ammonium nitrate, ${\text{NH}}_4{\text{NO}}_3$, are used as fertilisers. These salts have different percentages by mass of nitrogen. They have the same effect as each other on the pH of wet neutral soil. Which row is correct?

The equation shows a reaction that occurs between carbon monoxide and nitrogen monoxide in a catalytic converter. $$2\text{CO(g)}+2\text{NO(g)}\to 2{\text{CO}}_2(\text{g})+{\text{N}}_2(\text{g})$$ Which statement is correct? A The catalyst used is finely divided iron. B The reaction prevents greenhouse gas emissions into the atmosphere. C The reaction reduces the possibility of the formation of photochemical smog. D The reaction results in increased ozone depletion.

Which compound has the molecular formula ${\text{C}}_6{\text{H}}_{10}\text{O}$?

The general formula for a non-cyclic alcohol is ${\text{C}}_n{\text{H}}_{2n+1}\text{OH}$. How many different structural isomers are there for $n=3$ and $n=4$?

Compound X, ${\text{C}}_5{\text{H}}_{10}{\text{O}}_3$, has one chiral carbon atom per molecule. Compound X produces bubbles with $\text{Na}$ but not with ${\text{Na}}_2{\text{CO}}_3$. Which formula could represent compound X? A $({\text{CH}}_3{)}_2{\text{C(OH)CO}}_2{\text{CH}}_3$ B ${\text{HOCH}}_2{\text{CH(CH}}_3){\text{CO}}_2{\text{CH}}_3$ C ${\text{CH}}_3{\text{CH}}_2{\text{C(CH}}_3)(\text{OH}){\text{CO}}_2\text{H}$ D ${\text{CH}}_3{\text{CH(OH)CH(CH}}_3){\text{CO}}_2\text{H}$

Ethane reacts with an excess of chlorine in the presence of ultraviolet light to form a mixture of products. How many of these products contain two carbon atoms and one or more chlorine atoms? A 6 B 7 C 8 D 9

When bromoethane reacts with hot ethanolic sodium hydroxide a colourless gas is formed. This gas decolourises aqueous bromine. What is the colourless gas? A 1,2-dibromoethane B ethanol C ethene D hydrogen bromide

Alkynes are hydrocarbons that contain one triple $\text{C}\equiv \text{C}$ bond. Like alkenes, alkynes take part in addition reactions. A saturated compound can be formed. For example, ethyne, $\text{H}-\text{C}\equiv \text{C}-\text{H}$, reacts with an excess of hydrogen to form ethane. Propyne, ${\text{C}}_3{\text{H}}_4$, undergoes an addition reaction with an excess of hydrogen bromide in two stages. Markovnikov's rule applies to the addition of $\text{HBr}$ at each stage. What is the main product obtained when propyne reacts with an excess of hydrogen bromide? A ${\text{CH}}_2{\text{BrCH}}_2{\text{CH}}_2\text{Br}$ B ${\text{CH}}_3{\text{CH}}_2{\text{CHBr}}_2$ C ${\text{CH}}_3{\text{CHBrCH}}_2\text{Br}$ D ${\text{CH}}_3{\text{CBr}}_2{\text{CH}}_3$

Bromine reacts with alkenes by an electrophilic addition mechanism in which a cation is formed as an intermediate. Which mixture will produce the most stable intermediate cation? A 3,3-dimethylpent-1-ene + bromine B ethene + bromine C methylpropene + bromine D propene + bromine

Halogenoalkanes react with hot ethanolic potassium cyanide. The reaction mechanism is either ${\text{S}}_{\text{N}}1$ or ${\text{S}}_{\text{N}}2$. Which statement is correct? A All secondary halogenoalkanes react by the ${\text{S}}_{\text{N}}2$ mechanism only. B Both the halogenoalkane and the cyanide ion are involved in the initial step of the ${\text{S}}_{\text{N}}1$ mechanism. C Chloroethane reacts with cyanide ions by the ${\text{S}}_{\text{N}}1$ mechanism only. D The ${\text{S}}_{\text{N}}2$ mechanism involves a short-lived negatively charged transition state.

X, Y and Z are three isomeric alcohols.

Separate samples of each alcohol are warmed with a mild oxidising agent and the results noted. One of these alcohols, when dehydrated, will give a pair of cis-trans isomers with molecular formula ${\text{C}}_5{\text{H}}_{10}$. Which row is correct?

Compound G gives a pale yellow precipitate with alkaline ${\text{I}}_2(\text{aq})$. What could be compound G? A pentan-1-ol B pentan-2-ol C pentan-3-ol D 2-methylpentan-2-ol

The mechanism for the reaction between ethanal and hydrogen cyanide starts with the step shown. What is the correct structure of the intermediate ion formed, and what is the next step in this mechanism?

Which compound reacts with 2,4-dinitrophenylhydrazine reagent but does not react with Tollens' reagent? A ${\text{CH}}_3{\text{COCO}}_2\text{H}$ B ${\text{CH}}_3\text{CH(OH)CHO}$ C ${\text{CH}}_3\text{COCHO}$ D ${\text{CH}}_3{\text{CH(OH)CH}}_3$

Compound X has stereoisomers and forms a precipitate when warmed with Fehling's reagent. What could be the structure of compound X?

Which reaction will form propanoic acid? A acidic hydrolysis of propyl ethanoate B alkaline hydrolysis of ethyl propanoate C acidic hydrolysis of propanenitrile D acidic hydrolysis of ethanenitrile

Lactide is an intermediate in the manufacture of a synthetic fibre. Which compound, on heating with an acid catalyst, can produce lactide? A hydroxyethanoic acid B 2-hydroxybutanoic acid C 2-hydroxypropanoic acid D 3-hydroxypropanoic acid

The diagram shows the relative abundance of different isotopes of lead in a sample of lead ore. The abundance of 208 is half that of 206. The abundances of 208 and 209 are equal. What is the relative atomic mass of the lead in the sample? A 207.00 B 207.25 C 207.50 D 207.67