Oct/Nov 2024

In this question Q stands for a halogen atom. Magnesium and calcium both make a compound with chlorine and a compound with bromine. One of these compounds includes: • the Group 2 element with the greater first ionisation energy and • the Group 17 element with the greater Q-Q bond energy. What is the formula of this compound?

The Periodic Table: chemical periodicity

The three processes shown are listed below. 1. $\text{H}^+(\text{aq}) + \text{OH}^-(\text{aq}) \rightarrow \text{H}_2\text{O}(\text{l})$ 2. $\text{CH}_4(\text{g}) + 2\text{O}_2(\text{g}) \rightarrow \text{CO}_2(\text{g}) + 2\text{H}_2\text{O}(\text{l})$ 3. $\text{NH}_3(\text{g}) \rightarrow \text{NH}_3(\text{l})$ Which one of the following statements is correct?

Chemical energetics

In alkaline solution, $\text{MnO}_4^-$ ions oxidise $\text{SO}_3^{2-}$ ions to form $\text{SO}_4^{2-}$ ions. At the same time, the $\text{MnO}_4^-$ ions are reduced to $\text{MnO}_2$. What is the ratio of the two ions in the balanced chemical equation for this reaction?

Electrochemistry

At room temperature, lithium combines with nitrogen to produce solid $\text{Li}_3\text{N}$. As shown, three vessels of the same volume are joined by taps 1 and 2. The vessel on the left has been evacuated, the centre vessel contains the equilibrium system $\text{N}_2(\text{g}) + 3\text{H}_2(\text{g}) \rightleftharpoons 2\text{NH}_3(\text{g})$, and the vessel on the right contains lithium alone. Which action would make the equilibrium mixture contain the largest amount of ammonia?

Equilibria

If $0.20\,\text{mol}$ of hydrogen gas and $0.15\,\text{mol}$ of iodine gas are heated to $723\,\text{K}$ and allowed to reach equilibrium, the equilibrium mixture includes $0.26\,\text{mol}$ of hydrogen iodide. The reaction is represented by the equation below. $\text{H}_2(\text{g}) + \text{I}_2(\text{g}) \rightleftharpoons 2\text{HI}(\text{g})$ What is the correct equilibrium constant expression for $K_c$?

Equilibria

Under acidic conditions, iodine undergoes a substitution reaction with propanone. $\text{CH}_3\text{COCH}_3(\text{aq}) + \text{I}_2(\text{aq}) \rightarrow \text{CH}_3\text{COCH}_2\text{I}(\text{aq}) + \text{HI}(\text{aq})$ The reaction kinetics are studied with a colorimeter. As $\text{I}_2$ reacts, the yellow/brown colour of $\text{I}_2(\text{aq})$ disappears to give a colourless solution, so the absorbance of the solution changes. A calibration curve graph is first made using known concentrations of $\text{I}_2(\text{aq})$, and the absorbance is then recorded as the reaction continues. What is the reaction rate at $20\,\text{s}$?

Reaction kinetics

The diagram depicts a Boltzmann distribution curve, and the axes have no labels. X and Y are points on the vertical axis. What do X and Y both represent?

Reaction kinetics

What is the acid-base character and structure of $\text{SO}_2$?

Chemical bonding

Elements X and Y both belong to Period 3 of the Periodic Table. Element X is either phosphorus or sulfur. Element Y is either sodium or magnesium. The oxide of element X reacts with water to form a solution that contains the aqueous anion $\text{XO}_4^{2-}$. One mole of element Y combines with one mole of chlorine molecules. By the end of the reaction, every particle of element Y and every chlorine molecule has been completely consumed. Which elements are X and Y?

Atoms, molecules and stoichiometry

Q is a semiconductor. When the chloride of Q reacts with water, white fumes and an acidic solution are formed. Which Period 3 element is Q?

The Periodic Table: chemical periodicity

V and W are two compounds. Each contains a different Group 2 element. A separate sample of each solid is placed in water, the mixture is shaken, and the pH of the solution formed is measured. The pH readings are: V = $13.6$, W = $9.4$. Which row could be used to identify V and W?

Group 2

Compound X is formed from the two elements Y and Z. Element Y lies in Period 2 of the Periodic Table. For a single atom of Y, the p sub-shell contains electrons in all three orbitals; however, only one of those three orbitals is completely filled. Element Z lies in Period 3 of the Periodic Table. For a single atom of Z, only two orbitals in the p sub-shell contain electrons. What is the formula of compound X?

The Periodic Table: chemical periodicity

When L is heated, it breaks down. One product formed is gas M. M then reacts with unburned hydrocarbons and produces peroxyacetyl nitrate, PAN. What might the formula of L be?

Nitrogen and sulfur

In reaction 1, concentrated sulfuric acid is added to potassium chloride, and the gas given off is passed through aqueous potassium iodide solution. In reaction 2, potassium chloride is dissolved in aqueous ammonia and the resulting solution is then mixed with aqueous silver nitrate. What are the observations for reactions 1 and 2?

Group 17

The table is about the hydrogen halides. Which row is correct?

Group 17

On the surface of the catalytic converter in a car exhaust system, $7.5\,\text{g}$ of nitrogen monoxide reacts with $7.0\,\text{g}$ of carbon monoxide. What total volume do the product gases occupy at room conditions?

Atoms, molecules and stoichiometry

Three statements concerning ammonia molecules and ammonium ions are listed below. Which of these statements are correct?

Chemical bonding

Ethene is combined with steam in the presence of sulfuric acid. $\text{C}_2\text{H}_4 + \text{H}_2\text{O} \rightarrow \text{CH}_3\text{CH}_2\text{OH}$ What type of reaction is shown here?

Chemical bonding

Compound Z has the molecular formula $\text{C}_4\text{H}_8\text{O}_2$. In the presence of concentrated $\text{H}_2\text{SO}_4$, compound Z reacts with propan-1-ol. The diagram presents the skeletal formulae for three compounds, S, T and U. Which skeletal formulae could be formed as the products of the reaction between compound Z and propan-1-ol?

Carboxylic acids and derivatives

Geraniol and nerol are isomers of one another. What kind of isomerism is being shown?

Atoms, molecules and stoichiometry

Which compound possesses the largest number of stereoisomers?

Hydrocarbons

Vitamin A includes retinol. If the conditions are suitable, acidified $\text{KMnO}_4(aq)$ can be used to cleave $\text{C}=\text{C}$ bonds. Once these bonds have been cleaved, the resulting fragments may undergo additional oxidation. In what conditions is acidified $\text{KMnO}_4(aq)$ used, and what are the final oxidation products likely to contain?

Electrochemistry

Glauber’s salt is made up of crystals of hydrated sodium sulfate, $\text{Na}_2\text{SO}_4 \cdot x\text{H}_2\text{O}$, and it is used in the production of detergents. A sample of Glauber’s salt was heated, and $1.91\,\text{g}$ of water was driven off, leaving $1.51\,\text{g}$ of anhydrous $\text{Na}_2\text{SO}_4$. What is the value of $x$ in $\text{Na}_2\text{SO}_4 \cdot x\text{H}_2\text{O}$?

Atoms, molecules and stoichiometry

The displayed structure of limonene is given. How many moles of carbon dioxide and water are formed when a sample of limonene is completely combusted in oxygen?

Atoms, molecules and stoichiometry

The reaction between chlorine and methane takes place in the presence of light. What role does the light play?

Reaction kinetics

If X is combined with NaOH(aq) and heated under reflux, pentan-2-ol is produced. Which organic product is formed when X is heated with a solution of KCN dissolved in ethanol?

Halogen compounds

1-chlorobutane and 1-iodobutane each undergo reaction with aqueous sodium hydroxide through a nucleophilic substitution mechanism. Under identical conditions, which reaction occurs at the highest rate, and what mechanism is used by that reaction?

Halogen compounds

Compound Y undergoes reaction with alkaline $\text{I}_2$(aq). If the reaction mixture is then acidified, a dicarboxylic acid is formed. The formula of this dicarboxylic acid is $\text{HOOC-R-COOH}$, where R is made up of one or more $\text{CH}_2$ groups. Which compound is Y?

Carbonyl compounds

When warmed with dilute acidified potassium dichromate(VI), which alcohol can form just one oxidation product?

Hydroxy compounds

Which compound, when it reacts with hydrogen cyanide, forms a compound containing a chiral centre?

Carbonyl compounds

The diagram illustrates three reactions involving ethanal. For each reaction, ethanal is present in excess. After each of the three reactions, observations are recorded. What colours are solution 1 and solids 2 and 3?

Carbonyl compounds

$(\text{CH}_3)_3\text{CCN}$ is converted into alcohol Y through the reaction pathway below. $(\text{CH}_3)_3\text{CCN} \xrightarrow[\text{reaction 1}]{\text{H}^+(\text{aq})} X \xrightarrow[\text{reaction 2}]{\text{LiAlH}_4} \text{alcohol Y}$ Which row gives the name of molecule X and the class of alcohol Y?

Chemical bonding

The diagram illustrates part of an addition polymer. This polymer is formed from two different monomers. What are the names of the two monomers required to make this polymer?

Chemical bonding

Which contains the largest number of the named particles?

Atoms, molecules and stoichiometry

The diagram illustrates the mass spectrum of a chlorine sample. Peaks V, W, X, Y and Z are marked. Which of the following statements about this spectrum are correct?

Atomic structure

Phosphorus combines with hydrogen to produce phosphine, $\text{PH}_3$. This substance can react with a hydrogen ion, $\text{H}^+$. What kind of interaction takes place between $\text{PH}_3$ and $\text{H}^+$?

Chemical bonding

The graphs illustrate patterns in four physical properties of the elements in Period 3, apart from argon. Which graph shows electronegativity on the $y$-axis?

The Periodic Table: chemical periodicity

Tin occurs in two forms: grey tin and white tin. The properties of grey tin and white tin are listed below. Grey tin: boiling point $2543\,\text{K}$, no electrical conductivity in solid or liquid, brittle. White tin: boiling point $2533\,\text{K}$, good electrical conductivity in solid and liquid, malleable. Which structural change could occur as grey tin is converted into white tin?

Chemical bonding

Which solid is arranged in a simple molecular lattice?

States of matter

The standard enthalpy change of combustion of carbon is $-394\,\text{kJ mol}^{-1}$. The standard enthalpy change of combustion of hydrogen is $-286\,\text{kJ mol}^{-1}$. The standard enthalpy change of formation of butane is $-129\,\text{kJ mol}^{-1}$. Determine the standard enthalpy change of combustion of butane.

Chemical energetics

Which species has a different electron count from the other three?

Atomic structure

The following standard enthalpy change of formation values are supplied. $\Delta H_f^\circ[\text{VCl}_2] = -452\,\text{kJ mol}^{-1}$ and $\Delta H_f^\circ[\text{VCl}_3] = -573\,\text{kJ mol}^{-1}$. What is the enthalpy change for the reaction $3\text{VCl}_2 \rightarrow 2\text{VCl}_3 + \text{V}$?

Chemical energetics

Some equations for reactions of hydrogen peroxide are shown. (1) $2\text{Fe}^{2+} + \text{H}_2\text{O}_2 + 2\text{H}^+ \rightarrow 2\text{Fe}^{3+} + 2\text{H}_2\text{O}$. (2) $2\text{MnO}_4^- + 5\text{H}_2\text{O}_2 + 6\text{H}^+ \rightarrow 2\text{Mn}^{2+} + 8\text{H}_2\text{O} + 5\text{O}_2$. (3) $2\text{Fe}^{3+} + \text{H}_2\text{O}_2 + 2\text{OH}^- \rightarrow 2\text{Fe}^{2+} + \text{O}_2 + 2\text{H}_2\text{O}$. In which reaction is hydrogen peroxide acting as a reducing agent?

Electrochemistry

The reaction equation for aqueous thiosulfate ions, $\text{S}_2\text{O}_3^{2-}$, reacting with aqueous dioxo-vanadium ions, $\text{VO}_2^+$, is given below. $2\text{S}_2\text{O}_3^{2-} + x\text{VO}_2^+ + y\text{H}^+ \rightarrow \text{S}_4\text{O}_6^{2-} + z\text{VO}^{2+} + 2\text{H}_2\text{O}$. Which row gives two statements that are both correct for this reaction equation?

Electrochemistry

When a small quantity of solid $\text{Ca}_5(\text{PO}_4)_3\text{OH}$ is put into a beaker of water, an equilibrium is established. $\text{Ca}_5(\text{PO}_4)_3\text{OH}(s) \rightleftharpoons 5\text{Ca}^{2+}(aq) + 3\text{PO}_4^{3-}(aq) + \text{OH}^-(aq)$. Which compound, if added to this equilibrium mixture, causes the quantity of $\text{Ca}_5(\text{PO}_4)_3\text{OH}(s)$ present to increase?

Equilibria

Gaseous hydrogen reacts with gaseous iodine to produce gaseous hydrogen iodide. $\text{H}_2\text{(g)} + \text{I}_2\text{(g)} \rightleftharpoons 2\text{HI}\text{(g)}$ For an experiment, $2.0\,\text{mol}$ of hydrogen and $2.0\,\text{mol}$ of iodine are introduced into a sealed container with a volume of $1.0\,\text{dm}^3$. The $K_c$ for this reaction at the stated conditions is $9.0$. What number of moles of hydrogen iodide is present when equilibrium is reached?

Equilibria

What causes the rate of a gaseous reaction to rise when the pressure is increased while the temperature stays constant?

Reaction kinetics

The Boltzmann distribution for a gas mixture that can react is shown. The two curves give the gas mixture at $25\,^{\circ}\text{C}$ and at $35\,^{\circ}\text{C}$. The activation energies for the catalysed reaction and the uncatalysed reaction are shown. Which row is the correct one?

Reaction kinetics

Which oxide does not dissolve in aqueous sodium hydroxide?

The Periodic Table: chemical periodicity

Sodium and sulfur are each burned on their own in oxygen. Each reaction produces a flame of a different colour. Which row is correct?

The Periodic Table: chemical periodicity

X and Y are elements of Period 3 in the Periodic Table. Y has a higher atomic number than X. The stable ion produced by Y has a larger radius than the stable ion produced by X. The stable ion produced by Y contains $18$ electrons. Which row is the correct one?

The Periodic Table: chemical periodicity

Which factor makes helium have a higher first ionisation energy than hydrogen?

The Periodic Table: chemical periodicity

X is a Group 2 element that lies in either Period 3 or Period 5. $X(\text{OH})_2$ has a lower solubility in water than $\text{Ca(OH)}_2$. If $X(\text{NO}_3)_2$ is heated, it breaks down. Which row is the correct one?

Group 2

Which statement about magnesium and barium, or about their compounds, is correct?

Group 2

The colours shown by the silver halides $\text{AgCl}$, $\text{AgBr}$ and $\text{AgI}$ are different. Their solubilities in aqueous ammonia are also not the same. Which row is correct?

Group 17

The term ‘chlorate’ describes an anion containing only chlorine and oxygen. In a molecule of $\text{ICl}$, the iodine atom has oxidation number $x$ and the chlorine atom has oxidation number $y$. When $\text{ICl}$ is mixed with $\text{H}_2\text{O}$, the iodine is reduced. $4\text{ICl} + 2\text{H}_2\text{O} \rightarrow 4\text{HCl} + \text{O}_2 + 2\text{I}_2$ Which statement correctly gives the value of $x$ or $y$?

Electrochemistry

Which statement is right?

Atoms, molecules and stoichiometry

The diagram illustrates the structural formula of hydrocarbon molecule Q. How many of the carbon atoms in molecule Q are $sp^2$ hybridised?

Chemical bonding

Compound X occurs in the cell walls of certain bacteria. Its structural formula is given. compound X $\text{CH}_3(\text{CH}_2)_{17}\text{CH}=\text{CH}(\text{CH}_2)_{17}\text{CH(OH)CH(CH}_3)\text{CO}_2\text{H}$ How many stereoisomers can exist for this structural formula?

An introduction to AS Level organic chemistry

Only structural isomerism should be taken into account when answering this question. How many straight-chain isomers have molecular formula $\text{C}_4\text{H}_8\text{Cl}_2$?

Atoms, molecules and stoichiometry

Which statement applies to all nucleophiles?

An introduction to AS Level organic chemistry

The figure outlines a synthetic pathway for making 1-methylcyclohexanol. $\text{(methylcyclohexene)} \xrightarrow{\text{HBr}} \text{product X} \xrightarrow[\text{heat}]{\text{reagent Y}} \text{1-methylcyclohexanol}$ What is the identity of reagent Y?

Organic synthesis

A $0.216\,\text{g}$ portion of aluminium carbide is allowed to react with an excess of water, forming methane gas. No other carbon-containing product is produced in this reaction. The methane gas is then burned completely in $\text{O}_2$, giving only $\text{H}_2\text{O}$ and $\text{CO}_2$. The volume of $\text{CO}_2$ generated at room temperature and pressure is $108\,\text{cm}^3$. What is the formula of aluminium carbide?

Atoms, molecules and stoichiometry

X and Y are the reagents needed to change 1-bromopropane into butanoic acid. $\text{CH}_3\text{CH}_2\text{CH}_2\text{Br} \xrightarrow{X} \text{CH}_3\text{CH}_2\text{CH}_2\text{CN} \xrightarrow{Y} \text{CH}_3\text{CH}_2\text{CH}_2\text{CO}_2\text{H}$ What are the correct identities of reagents X and Y?

Organic synthesis

The table presents three different combinations of reagents and reaction conditions. 1. $\text{CH}_2\text{C(CH}_3)\text{CH}_3$ together with $\text{HCl(g)}$ at room temperature 2. $\text{CH}_3\text{C(CH}_3)(\text{OH})\text{CH}_3$ together with $\text{SOCl}_2$ at room temperature 3. $\text{CH}_3\text{CH(CH}_3)\text{CH}_3$ together with $\text{Cl}_2$ in the presence of ultraviolet light Which of these combinations could be used to make 2-chloro-2-methylpropane as one of the organic products?

Halogen compounds

Which structures are the only products formed when butan-2-ol is heated with concentrated $\text{H}_2\text{SO}_4$?

Hydroxy compounds

The compound ‘leaf alcohol’ is one cause of the aroma of newly cut grass. leaf alcohol $\text{CH}_3\text{CH}_2\text{CH=CHCH}_2\text{CH}_2\text{OH}$ What compound will be formed when ‘leaf alcohol’ is oxidised with an excess of hot acidified $\text{K}_2\text{Cr}_2\text{O}_7\text{(aq)}$?

Hydroxy compounds

Compound X: - shows no reaction with Tollens’ reagent - gives a yellow precipitate with alkaline $\text{I}_2\text{(aq)}$ - shows no reaction with sodium. What could be the identity of X?

Carbonyl compounds

Which compound is able to undergo nucleophilic addition?

Carbonyl compounds

$\text{C}_2\text{H}_5\text{COOCH}_3$ is hydrolysed with aqueous acid. The resulting products are then treated with $\text{LiAlH}_4$ to give two molecules Y and Z. What are the identities of molecules Y and Z?

Carboxylic acids and derivatives

A portion of propanoic acid with a mass of $3.70\,\text{g}$ is reacted with excess magnesium. Another portion of propanoic acid with a mass of $3.70\,\text{g}$ is reacted with excess sodium. In each case, the reaction goes to completion and a gas is produced. Which row is correct?

Atoms, molecules and stoichiometry

Which of the following statements about $\text{H}_2\text{C}=\text{C}(\text{CH}_3)\text{CH}_2\text{CO}_2\text{CH}_3$ is correct?

Carboxylic acids and derivatives

Synthetic resins may be formed through polymerisation of a range of monomers, including prop-2-en-1-ol, $\text{CH}_2=\text{CHCH}_2\text{OH}$. Which structure shows the repeat unit of the polymer poly(prop-2-en-1-ol)?

Chemical bonding

On the surface of the catalytic converter in a petrol-engined car, a reaction occurs between two gases. In this reaction, four reactant molecules form three product molecules. Which two reactant gases could be involved in this reaction?

Atoms, molecules and stoichiometry

The structure of vitamin C is shown below. In the mass spectrum of vitamin C, the molecular ion peak has an $m/\!e$ value of $176$ and a relative abundance of $7.0\%$. Determine the abundance of the $\text{M}+1$ peak.

Analytical techniques

An ion is composed of $1$ nitrogen atom and $2$ hydrogen atoms. It has an $\text{H-N-H}$ bond angle of about $105^\circ$. Which row is correct?

Chemical bonding

What causes $\text{ICl}$ to have a higher boiling point than $\text{Br}_2$?

States of matter

For this question, you may take nitrogen to be an ideal gas. One atmosphere pressure $=101\,\text{kPa}$. What volume is occupied by $1.0\,\text{g}$ of nitrogen at $50^\circ\text{C}$ and a pressure of $2.0$ atmospheres?

States of matter

Which statement correctly describes the properties linked to the different types of bonding involved?

Chemical bonding

Which reaction has an enthalpy change that is an enthalpy change of formation?

Chemical energetics

For this question, Q stands for a halogen atom. Magnesium and calcium each make one compound with chlorine and one compound with bromine. One of the compounds has: • the Group 2 element with the greater first ionisation energy and • the Group 17 element with the larger Q-Q bond energy. What formula does this compound have?

Group 2

The following three processes are given. 1. $\text{H}^+(\text{aq}) + \text{OH}^-(\text{aq}) \rightarrow \text{H}_2\text{O}(\ell)$ 2. $\text{CH}_4(\text{g}) + 2\text{O}_2(\text{g}) \rightarrow \text{CO}_2(\text{g}) + 2\text{H}_2\text{O}(\ell)$ 3. $\text{NH}_3(\text{g}) \rightarrow \text{NH}_3(\ell)$ Which statement is right?

Chemical energetics

In alkaline solution, $\text{MnO}_4^- $ ions oxidise $\text{SO}_3^{2-}$ ions into $\text{SO}_4^{2-}$ ions, and the $\text{MnO}_4^-$ ions are reduced to $\text{MnO}_2$. What ratio of these two ions is present in the balanced chemical equation for this reaction?

Electrochemistry

When lithium is exposed to nitrogen at room temperature, solid $\text{Li}_3\text{N}$ is produced. As shown, three vessels with the same volume are joined by taps 1 and 2. In the central vessel, the equilibrium reaction is $\text{N}_2(\text{g}) + 3\text{H}_2(\text{g}) \rightleftharpoons 2\text{NH}_3(\text{g})$. Initially, taps 1 and 2 are shut, the left-hand vessel has been evacuated, the middle vessel contains the reaction mixture at equilibrium and the right-hand vessel contains lithium only. Which action would cause the equilibrium mixture to contain the maximum amount of ammonia?

Equilibria

A mixture is made by heating $0.20$ mol of hydrogen gas with $0.15$ mol of iodine gas at $723\,\text{K}$ until equilibrium is reached; the equilibrium mixture then has $0.26$ mol of hydrogen iodide. The equation for the reaction is $\text{H}_2(\text{g}) + \text{I}_2(\text{g}) \rightleftharpoons 2\text{HI}(\text{g})$. Which is the correct equilibrium constant expression for $K_c$?

Equilibria

Under acidic conditions, iodine undergoes a substitution reaction with propanone. $\text{CH}_3\text{COCH}_3(\text{aq}) + \text{I}_2(\text{aq}) \rightarrow \text{CH}_3\text{COCH}_2\text{I}(\text{aq}) + \text{HI}(\text{aq})$ The rate of this reaction is studied with a colorimeter. As the $\text{I}_2$ is consumed, the yellow/brown colour of the $\text{I}_2(\text{aq})$ solution becomes colourless, so the absorbance of the mixture changes. A calibration curve graph is produced from solutions of known $\text{I}_2(\text{aq})$ concentrations, and the absorbance is recorded while the reaction continues. What is the rate of reaction at $20\,\text{s}$?

Reaction kinetics

The diagram illustrates a Boltzmann distribution curve. The axes have not been labelled. X and Y are points on the vertical axis. What is shown by both X and Y?

Reaction kinetics

How would you describe the acid-base properties and structure of $\text{SO}_2$?

Nitrogen and sulfur

Elements X and Y both belong to Period 3 of the Periodic Table. X is either phosphorus or sulfur, and Y is either sodium or magnesium. An oxide of X reacts with water to produce a solution that contains the aqueous anion $\text{XO}_4^{2-}$. 1 mole of element Y reacts with 1 mole of chlorine molecules. By the end of the reaction, every particle of element Y and every chlorine molecule has been completely used. What are elements X and Y?

The Periodic Table: chemical periodicity

Q is a semiconductor. Its chloride reacts with water, producing white fumes and an acidic solution. Which Period 3 element is Q?

The Periodic Table: chemical periodicity

V and W are two compounds, and each contains a different Group 2 element. A sample of each solid is put into water, then shaken, and the pH of the solution formed is measured. The results are shown: V has pH $13.6$ and W has pH $9.4$. Which row could be used to identify V and W?

Group 2

Compound X is formed from the two elements Y and Z. Y is an element in Period 2 of the Periodic Table. In a single atom of Y, every orbital in the p sub-shell is occupied, and just one of those three orbitals is fully occupied. Z is an element in Period 3 of the Periodic Table. In a single atom of Z, only two orbitals in the p sub-shell are occupied. What is the formula of compound X?

The Periodic Table: chemical periodicity

Compound L breaks down upon heating. One of the substances produced is gas M. M reacts with unburned hydrocarbons to produce peroxyacetyl nitrate, PAN. What could be the formula of L?

Nitrogen and sulfur

For reaction 1, concentrated sulfuric acid is mixed with potassium chloride, and the gases formed are passed through aqueous potassium iodide solution. For reaction 2, potassium chloride is first dissolved in aqueous ammonia and the resulting solution is then added to aqueous silver nitrate. What observations would be made in reactions 1 and 2?

Group 17

The table is about the hydrogen halides. Which row is correct?

Group 17

$7.5\,\text{g}$ of nitrogen monoxide is reacted with $7.0\,\text{g}$ of carbon monoxide on the surface of the catalytic converter in a car exhaust system. What total volume do the product gases occupy at room conditions?

Atoms, molecules and stoichiometry

Three statements concerning ammonia molecules and ammonium ions are listed. Which of the statements are correct?

Chemical bonding

Ethene combines with steam in the presence of sulfuric acid. $\text{C}_2\text{H}_4 + \text{H}_2\text{O} \rightarrow \text{CH}_3\text{CH}_2\text{OH}$ What kind of reaction is this?

Hydrocarbons

Compound Z has the molecular formula $\text{C}_4\text{H}_8\text{O}_2$. In the presence of concentrated $\text{H}_2\text{SO}_4$, compound Z reacts with propan-1-ol. The skeletal formulae of three compounds, S, T and U, are shown in the diagram. What skeletal formulae could represent the products formed when compound Z reacts with propan-1-ol?

Carboxylic acids and derivatives

Geraniol and nerol are isomers of one another. What kind of isomerism is shown here?

An introduction to AS Level organic chemistry

Which compound has the highest number of stereoisomers?

Chemical bonding

Retinol is a constituent of Vitamin A. When the conditions are suitable, acidified $\text{KMnO}_4\text{(aq)}$ may be used to cleave $\text{C=C}$ bonds. Once these bonds have been cleaved, the fragments may undergo further oxidation. In what conditions is acidified $\text{KMnO}_4\text{(aq)}$ used, and what are the final oxidation products made up of?

Electrochemistry

Glauber’s salt is made up of crystals of hydrated sodium sulfate, $\text{Na}_2\text{SO}_4 \cdot x\text{H}_2\text{O}$, and it can be used in detergent manufacture. A sample of Glauber’s salt was heated, and $1.91\,\text{g}$ of water was driven off, leaving $1.51\,\text{g}$ of anhydrous $\text{Na}_2\text{SO}_4$. What is the value of $x$ in $\text{Na}_2\text{SO}_4 \cdot x\text{H}_2\text{O}$?

Atoms, molecules and stoichiometry

The displayed diagram shows the structure of limonene. What number of moles of carbon dioxide and water are formed when a sample of limonene is completely combusted in oxygen?

Atoms, molecules and stoichiometry

The reaction between chlorine and methane takes place in the presence of light. What is the purpose of the light?

Reaction kinetics

When X is treated with $\text{NaOH(aq)}$ and heated under reflux, pentan-2-ol is produced. Which organic product is formed when X is heated with a solution of $\text{KCN}$ dissolved in ethanol?

Halogen compounds

1-chlorobutane and 1-iodobutane each undergo reaction with aqueous sodium hydroxide via a nucleophilic substitution mechanism. Under identical conditions, which reaction has the highest rate, and which mechanism is used in this reaction?

Halogen compounds

Compound Y undergoes reaction with alkaline $\text{I}_2\text{(aq)}$. If the resulting mixture is then acidified, a dicarboxylic acid is formed. This dicarboxylic acid has formula $\text{HOOC-R-COOH}$, with R made up of one or more $\text{CH}_2$ groups. Which compound is Y?

Carbonyl compounds

Which alcohol produces only one possible oxidation product when it is warmed with dilute acidified potassium dichromate(VI)?

Hydroxy compounds

Which compound forms a product with a chiral centre when it reacts with hydrogen cyanide?

Chemical bonding

The diagram illustrates three reactions of ethanal. In every case, ethanal is used in excess. Ethanal $\text{CH}_3\text{CHO}$ reacts: - with acidified $\text{K}_2\text{Cr}_2\text{O}_7$ (heat) to produce solution 1, - with alkaline $\text{I}_2\text{(aq)}$ (heat) to produce solid 2, - with Fehling’s solution (boil) to produce solid 3. After each of the three reactions, observations are recorded. What colours are observed for solution 1 and for solids 2 and 3?

Carbonyl compounds

$(\text{CH}_3)_3\text{CCN}$ is converted into alcohol Y by the reaction pathway shown below. $(\text{CH}_3)_3\text{CCN} \xrightarrow{\text{H}^+\text{(aq)}} X \xrightarrow{\text{LiAlH}_4}$ alcohol Y Which row gives the name of molecule X and the type of alcohol Y?

Carboxylic acids and derivatives

The diagram illustrates one part of an addition polymer. This polymer is produced from two different monomers. What are the names of the two monomers required to produce this polymer?

Chemical bonding

Which contains the largest number of the named particles?

Atoms, molecules and stoichiometry

The diagram presents the mass spectrum of a chlorine sample. The peaks are labelled V, W, X, Y and Z. Which of the following statements about this spectrum are correct?

Analytical techniques

Phosphorus combines with hydrogen to produce phosphine, $\text{PH}_3$. This substance is able to react with a hydrogen ion, $\text{H}^+$. What kind of interaction takes place between $\text{PH}_3$ and $\text{H}^+$?

Chemical bonding

The graphs illustrate patterns in four physical properties of the Period 3 elements, not including argon. Which graph places electronegativity on the $y$-axis?

The Periodic Table: chemical periodicity

The element tin occurs in two forms: grey tin and white tin. Some properties of grey tin and white tin are listed below. Boiling point / K: grey tin $2543$, white tin $2533$ Electrical conductivity: grey tin none in solid or liquid, white tin good in solid and liquid Malleability: grey tin brittle, white tin malleable What structural change might happen when grey tin changes to white tin?

Chemical bonding

Which solid is arranged in a simple molecular lattice structure?

States of matter

The standard enthalpy change of combustion of carbon is $-394\,\text{kJ mol}^{-1}$. The standard enthalpy change of combustion of hydrogen is $-286\,\text{kJ mol}^{-1}$. The standard enthalpy change of formation of butane is $-129\,\text{kJ mol}^{-1}$. Calculate the standard enthalpy change of combustion of butane?

Chemical energetics