Oct/Nov 2022

Which row gives the apparatus that is most suitable for the measurement stated?

Experimental design

Elements X and Y combine to make compound XY. Element Y has a greater number of electrons in its outer shell than element X. In the molten state, compound XY allows electricity to pass through it. Which row correctly gives the electron transfer that takes place during the reaction and the bonding type in compound XY?

Ion and ionic bonds

Which compound contains the greatest number of single bonds in a single molecule?

Simple molecules and covalent bonds

The formula for ammonium metavanadate is $\text{NH}_4\text{VO}_3$. It is made up of $\text{NH}_4$ ions and $\text{VO}_3$ ions. What charges do these ions have?

Ion and ionic bonds

What mass of oxygen gas is needed to react completely with exactly $16\,\text{g}$ of sulfur to produce sulfur dioxide, $\text{SO}_2$?

Relative masses of atoms and molecules

Ruthenium has atomic number $44$. One oxide of ruthenium is the black solid, X. A sample of X with mass $5.79\,\text{g}$ contains $1.39\,\text{g}$ of oxygen. Determine the empirical formula of X.

Formulae

A $250\,\text{cm}^3$ sample of $1.0\,\text{mol dm}^{-3}$ hydrochloric acid reacts with an excess of solid sodium carbonate. The equation is given below. $\text{2HCl(aq)} + \text{Na}_2\text{CO}_3\text{(s)} \rightarrow \text{2NaCl(aq)} + \text{CO}_2\text{(g)} + \text{H}_2\text{O(l)}$ What volume of carbon dioxide is formed when it is measured at room temperature and pressure?

The mole and the Avogadro constant

If excess aqueous barium chloride is added to $25.0\,\text{cm}^3$ of $1.00\,\text{mol dm}^{-3}$ sodium sulfate, a white precipitate of barium sulfate is produced. $\text{Na}_2\text{SO}_4\text{(aq)} + \text{BaCl}_2\text{(aq)} \rightarrow \text{BaSO}_4\text{(s)} + 2\text{NaCl(aq)}$ This precipitate is then filtered, washed, dried and weighed. A mass of $5.36\,\text{g}$ barium sulfate is obtained. Calculate the percentage yield of barium sulfate. $[M_r:\ \text{Na}_2\text{SO}_4,\ 142;\ \text{BaCl}_2,\ 208;\ \text{BaSO}_4,\ 233;\ \text{NaCl},\ 58.5]$

The mole and the Avogadro constant

An aqueous solution of copper(II) sulfate is electrolysed with inert electrodes. Which statement is correct?

Electrolysis

A concentrated aqueous solution of sodium chloride is electrolysed with inert electrodes. Which equation represents the reaction taking place at the anode?

Electrolysis

Which pair of equations correctly shows the reactions occurring at the anode and at the cathode during the electrolysis of molten silver bromide?

Electrolysis

A liquid, X, is separated by distillation from a mixture with the apparatus illustrated. While the distillation is taking place, the thermometer shows a temperature between $157\,^{\circ}\text{C}$ and $160\,^{\circ}\text{C}$. Which statement about liquid X is correct?

Separation and purification

Which pair of processes are both endothermic?

Exothermic and endothermic reactions

A sample of sulfuric acid is mixed with $10\,\text{g}$ of zinc granules. As the reaction takes place, a gas is formed. The reaction rate increases when a small quantity of copper is added. The copper remains unchanged at the end of the reaction. Which statement correctly describes this reaction?

Rate of reaction

The reaction rate between magnesium and dilute hydrochloric acid is being studied. The equation is shown. $\text{Mg(s)} + 2\text{HCl(aq)} \rightarrow \text{MgCl}_2\text{(aq)} + \text{H}_2\text{(g)}$ A measured mass of magnesium is placed into an excess of dilute hydrochloric acid. The hydrochloric acid concentration and the volume of hydrogen given off are recorded at regular time intervals. Which pair of graphs accurately represents the experimental results?

Rate of reaction

In which reaction is the substance that is underlined reduced?

Redox

Which change causes a decrease?

Redox

Thiosulfate ions, $\text{S}_2\text{O}_3^{2-}$, undergo reaction with iodine, $\text{I}_2$, in aqueous solution. $2\text{S}_2\text{O}_3^{2-}(aq) + \text{I}_2(aq) \rightarrow 2\text{I}^-(aq) + \text{S}_4\text{O}_6^{2-}(aq)$ During this reaction, the $\text{S}_2\text{O}_3^{2-}$ ions ........1........ electrons and are ........2........ . Which words best fill gaps 1 and 2?

Redox

The equation represents a reaction in the Contact process. $2\text{SO}_2(g) + \text{O}_2(g) \rightleftharpoons 2\text{SO}_3(g) \quad \Delta H = -196\,\text{kJ mol}^{-1}$ Which alteration would shift the equilibrium position to the left?

Reversible reactions and equilibrium

Some medicines include the magnesium salt of a fatty acid. Fatty acids are part of the homologous series of carboxylic acids and have one carboxylic acid group. State the carboxylic acid functional group and how many moles of a fatty acid react with 1 mole of magnesium?

Formulae, functional groups and terminology

Sodium sulfate, $\text{Na}_2\text{SO}_4$, and sodium hydrogensulfate, $\text{NaHSO}_4$, may each be made from aqueous sodium hydroxide and sulfuric acid. $2\text{NaOH}(aq) + \text{H}_2\text{SO}_4(aq) \rightarrow \text{Na}_2\text{SO}_4(aq) + 2\text{H}_2\text{O}(l)$ $\text{NaOH}(aq) + \text{H}_2\text{SO}_4(aq) \rightarrow \text{NaHSO}_4(aq) + \text{H}_2\text{O}(l)$ $50\,\text{cm}^3$ of $1\,\text{mol dm}^{-3}$ sodium hydroxide is used each time. Which row gives the correct volumes of $1\,\text{mol dm}^{-3}$ sulfuric acid needed to make a sample of sodium sulfate and a sample of sodium hydrogensulfate?

The mole and the Avogadro constant

Which substance is made to react with dilute sulfuric acid during the preparation of a pure sample of lead(II) sulfate?

Preparation of salts

An aqueous solution contains a salt, Y. When an aqueous solution X is added, a precipitate forms, and it dissolves again if more X is added. Which solution X and salt Y could this be?

Identification of ions and gases

Which of the following statements about sulfuric acid is correct?

The characteristic properties of acids and bases

There are two statements.

Elements, compounds and mixtures

In a reversible reaction, a solid reacts with hydrogen. Which metal, aluminium or iron, would catalyse this reaction, and how would it affect the equilibrium position?

Rate of reaction

Iron is produced in the blast furnace from the ore haematite. Which of the following statements is correct?

Extraction of metals

Three statements concerning the carbon cycle are provided.

Air quality and climate

Carbon is used to purify the water supply. Why is it used?

Water

Octane is an alkane that has eight carbon atoms in each molecule. What is the molecular formula for octane, and how does its boiling point compare with that of butane?

Alkanes

Which equation correctly shows the reaction between propane and chlorine?

Alkanes

Propanoic acid reacts with calcium carbonate, producing calcium propanoate, carbon dioxide and water. What is the equation for this reaction?

Preparation of salts

The monomer, $\text{CH}_3\text{CH}=\text{CHCH}_3$, can be used to form an addition polymer. In this addition polymer, the carbon atoms are linked together in a chain by C-C single bonds. Each carbon atom in the chain is also attached to at least one further atom or group of atoms. These are known as side groups. Which statement correctly describes the carbon atoms in the polymer chain formed from $\text{CH}_3\text{CH}=\text{CHCH}_3$?

Polymers

At the same pressure, which gas has the highest diffusion rate?

Diffusion

Which row correctly shows the arrangement of a polymer and the monomers that form it?

Polymers

The diagram displays the outer-shell electrons of the atoms of two elements, Q and R. The sulfate of Q does not dissolve in water. Element R is a gas at room temperature and pressure. Which row might be correct?

Atomic structure and the Periodic Table

Which of the following statements about iodine atoms and iodide ions is correct?

Ion and ionic bonds

The element chlorine has two isotopes, $^{35}_{17}\text{Cl}$ and $^{37}_{17}\text{Cl}$. In the Periodic Table, chlorine is shown as $^{35.5}_{17}\text{Cl}$. Which row gives the correct percentage of each isotope in a sample of chlorine found in nature?

Isotopes

What is the nucleon number for the uranium isotope, $^{235}_{92}\text{U}$?

Isotopes

Silicon dioxide has a giant structure. Every silicon atom is covalently bonded to four oxygen atoms. A section of the structure is shown. Which property would silicon dioxide be expected to have?

Giant covalent structures

Which item of apparatus would be most appropriate for measuring exactly $37.00\ \text{cm}^3$ of aqueous ammonia?

Experimental design

Which two pairs of atoms are joined by an equal number of bonds?

Simple molecules and covalent bonds

Boron trifluoride, $\text{BF}_3$, is a simple molecule. Each $\text{BF}_3$ molecule contains three covalent bonds. Every one of these bonds is formed by the sharing of one electron from the boron atom and one electron from a fluorine atom. What is unusual about the bonding in boron trifluoride?

Simple molecules and covalent bonds

Which equation correctly represents the reaction of carbon dioxide with magnesium hydroxide?

The characteristic properties of acids and bases

What mass of oxygen gas is needed to react completely with exactly $16\,\text{g}$ of sulfur to produce sulfur dioxide, $\text{SO}_2$?

The mole and the Avogadro constant

Which compound has an empirical formula that differs from its molecular formula?

Formulae

$4.0\,\text{g}$ of sodium hydroxide, $\text{NaOH}$, is added to $250\,\text{cm}^3$ of water in a graduated flask. A $25\,\text{cm}^3$ portion of this solution is then titrated using $0.50\,\text{mol dm}^{-3}$ hydrochloric acid. What volume of hydrochloric acid is needed to neutralise the alkali exactly?

Acid–base titrations

Dilute aqueous solutions of potassium chloride and magnesium chloride are combined. An aliquot of the resulting mixture is electrolysed with inert electrodes. What products may be formed at each electrode?

Electrolysis

The table presents several statements about electrolysis together with the explanation for why each statement is correct. Which row contains a correct statement and the correct explanation for why it is correct?

Electrolysis

Students suggested four cells for generating electricity in a school laboratory. Which cell would give the greatest voltage while still being safe to use?

Hydrogen–oxygen fuel cells

Nitrogen oxides can be produced in the atmosphere when lightning occurs. $\text{N}_2 + \text{O}_2 \rightarrow 2\text{NO}$ This reaction is endothermic. Which energy profile diagram is the correct one for this reaction?

Exothermic and endothermic reactions

When iron is allowed to react with dilute hydrochloric acid, hydrogen is produced. Because the iron contains impurities, some hydrogen sulfide gas is produced as well. Hydrogen sulfide gas dissolves in water. A mixture of gases can be dried by passing it through concentrated sulfuric acid. Which diagram shows apparatus that is suitable for preparing a pure, dry sample of hydrogen?

Separation and purification

Which pair of processes are both endothermic?

Exothermic and endothermic reactions

Magnesium reacts with dilute sulfuric acid. $\text{Mg}(s) + \text{H}_2\text{SO}_4(aq) \rightarrow \text{MgSO}_4(aq) + \text{H}_2(g)$ Which alterations to the conditions would give the slowest rate of hydrogen production?

Rate of reaction

Carbonates react with dilute acids to form carbon dioxide. A student uses excess carbonate and $100\,\text{cm}^3$ of $0.1\,\text{mol dm}^{-3}$ acid, then records the volume of gas produced at equal time intervals. These results are shown by line X on the graph. The student then repeats the experiment with $50\,\text{cm}^3$ of $0.2\,\text{mol dm}^{-3}$ acid while keeping all other conditions unchanged. Which line represents the results for the second experiment?

Rate of reaction

During the Contact process, sulfur is changed into sulfuric acid. A catalyst is included in the reaction mixture represented by the equation. $2\text{SO}_2 + \text{O}_2 \rightleftharpoons 2\text{SO}_3$ What is the purpose of the catalyst?

Reversible reactions and equilibrium

Which change results in a reduction?

Redox

When the conditions are right, iron reacts with chlorine to produce iron(III) chloride. $2\text{Fe} + 3\text{Cl}_2 \rightarrow 2\text{FeCl}_3$ Which of the following statements about this reaction is correct?

Redox

The equation represents a reaction in the Contact process. $2\text{SO}_2(g) + \text{O}_2(g) \rightleftharpoons 2\text{SO}_3(g) \quad \Delta H = -196\,\text{kJ mol}^{-1}$ Which change would shift the equilibrium position to the left?

Reversible reactions and equilibrium

The table gives the pH values for several substances that humans can eat or drink. Substances and pH values: $P: 6.6$, $Q: 3.1$, $R: 10.4$, $S: 7.8$ Which statement about these substances is true?

The characteristic properties of acids and bases

Solution X is introduced to a solid salt, so that gas Y is given off. Gas Y dissolves in water, forming a solution with a pH below $7$. What could X and Y be?

The characteristic properties of acids and bases

Which substance is used in the preparation of a pure sample of lead(II) sulfate and reacts with dilute sulfuric acid?

Preparation of salts

A sample of green crystals is tested using the procedures below. First, the crystals are dissolved in water, and the solution obtained is split into two parts. • Aqueous sodium hydroxide is added to the first part. A green precipitate, which dissolves in excess aqueous sodium hydroxide, is produced. The solution formed is warmed, and a gas is given off that turns litmus paper blue. • Dilute nitric acid is added to the second part, then aqueous barium nitrate is added. A white precipitate is produced. Which three ions are present in the green crystals?

Identification of ions and gases

A pure sample of a salt is produced by filtering the mixture and then evaporating the filtrate. Which pair of reagents would form the salt?

Preparation of salts

Which combination of conditions is used in the Contact process?

Preparation of salts

A section of the Periodic Table is shown. Which substance is a gas in the atmosphere that does not react easily?

Noble gases

Iron is extracted in a blast furnace from the ore haematite. Which statement is correct?

Extraction of metals

Pollution can be produced by oxides of carbon, nitrogen and sulfur. Which elements are capable of forming more than one oxide?

Oxides

A river flows through land used for cotton growing. The cotton farmers applied a large quantity of fertiliser to their fields. This led to eutrophication in the river water. Which option is correct?

Fertilisers

Which compound can be classified as an alkane?

Alkanes

This equation represents the reaction when butanol burns completely in air. $\text{C}_4\text{H}_9\text{OH}(l) + x\text{O}_2(g) \rightarrow y\text{CO}_2(g) + z\text{H}_2\text{O}(g)$ Determine the values of $x$, $y$ and $z$?

Formulae

Propanoic acid reacts with calcium carbonate, producing calcium propanoate, carbon dioxide and water. What equation represents this reaction?

Preparation of salts

Which row lists every element found in the polymers below? • nylon • poly(ethene) • Terylene

Polymers

State changes take place among solids, liquids and gases. gas $\xrightleftharpoons[P]{R}$ liquid $\xrightleftharpoons[Q]{S}$ solid What changes are happening at P, Q, R and S?

Solids, liquids and gases

A partial structure of a polyamide is shown. Which monomers could be used to make this polymer?

Polymers

The table gives details about certain oxides. structure: simple molecular effect of water: dissolves and forms an acid For which of nitrogen, phosphorus, sulfur and silicon could this description of their oxides be correct?

Oxides

Which statement concerning iodine atoms and iodide ions is correct?

Ion and ionic bonds

The table shows data for four substances. Which substance is an ionic compound?

Ion and ionic bonds

For the uranium isotope, $^{235}_{92}\text{U}$, what is its nucleon number?

Isotopes

An ionic compound is represented by the formula $\text{Al}_2\text{O}_3$. What charges do the ions carry?

Ion and ionic bonds

The figure shows a section of the Periodic Table. The following element symbols appear in approximately correct positions: Na, K, Ca, Sr, Ba, Cr, Fe, Ni, Zn, Ag, Al, Si, N, O, Cl. Use only the symbols of the elements shown in the diagram to answer the questions below. Each symbol may be used once, more than once or not at all. State the symbol of the element that:

Arrangement of elements

Carbon dioxide is a gas at room temperature.

Simple molecules and covalent bonds

Alkenes form a homologous series of hydrocarbons.

Alkenes

This question concerns ammonia and ammonium salts.

Fertilisers

This question concerns metals and metal compounds.

Extraction of metals

This question concerns compounds formed from nitrogen.

Reversible reactions and equilibrium

This question focuses on alcohols and polymers.

Polymers

This question deals with metals and metal compounds.

Alloys and their properties

Zinc powder is reacted with dilute hydrochloric acid. $\text{Zn} + 2\text{HCl} \rightarrow \text{ZnCl}_2 + \text{H}_2$ If $20.0\,\text{cm}^3$ of dilute hydrochloric acid is added to excess zinc, the volume of hydrogen gas obtained at room temperature and pressure is $60.0\,\text{cm}^3$. Calculate the concentration, in $\text{mol dm}^{-3}$, of the dilute hydrochloric acid.

The mole and the Avogadro constant

The diagram presents part of the Periodic Table. Use only the element symbols shown in the diagram to answer the questions below. Each symbol can be selected once, more than once, or not used at all. Give the symbol of the element that:

Arrangement of elements

This question concerns halogens and compounds of the halogens.

Group VII properties

The alkanes belong to a homologous series of hydrocarbons.

Alkanes

This item concerns ammonium sulfate, $(\text{NH}_4)_2\text{SO}_4$.

Fertilisers

This question concerns metals and metal compounds.

Extraction of metals

This question concerns nitrogen and oxides of nitrogen.

Reversible reactions and equilibrium

This question concerns carboxylic acids and polymers.

Polymers

This question concerns metals and metal compounds.

Metallic bonding

Magnesium carbonate is added to dilute hydrochloric acid. $\text{MgCO}_3 + 2\text{HCl} \rightarrow \text{MgCl}_2 + \text{CO}_2 + \text{H}_2\text{O}$ If $25.0\,\text{cm}^3$ of dilute hydrochloric acid is mixed with excess magnesium carbonate, the carbon dioxide obtained at room temperature and pressure has a volume of $120\,\text{cm}^3$. Calculate the concentration, in $\text{mol dm}^{-3}$, of the dilute hydrochloric acid.

The mole and the Avogadro constant

Two gases, A and B, are shown with their properties. Several apparatus arrangements, P, Q and R, for gas collection are also illustrated.

Solids, liquids and gases

A student carries out electrolysis on two aqueous solutions with the apparatus illustrated.

Electrolysis

Calcium carbonate reacts with dilute hydrochloric acid. $\text{CaCO}_3(s) + 2\text{HCl}(aq) \rightarrow \text{CaCl}_2(aq) + \text{CO}_2(g) + \text{H}_2\text{O}(l)$. A student studies how the rate of this reaction changes using three different hydrochloric acid concentrations.

Rate of reaction

A student receives two bottles marked A and B, together with dilute hydrochloric acid. One bottle holds $1.00\,\text{g}$ of solid potassium carbonate, $\text{K}_2\text{CO}_3$. The other bottle contains $1.00\,\text{g}$ of solid potassium hydrogencarbonate, $\text{KHCO}_3$.

Experimental design

Solution K is an aqueous sodium hydroxide, $\text{NaOH}$, solution. A student finds the concentration of solution K by titration.

Acid–base titrations

A student is supplied with aqueous copper(II) sulfate, aqueous aluminium sulfate and an aqueous solution labelled X.

Identification of ions and gases

A student sends electric current through an aqueous zinc sulfate solution with an inert anode and a zinc cathode whose mass is known.

Electrolysis

Three colourless gases A, B and C are given with the following properties: Gas A: denser than air, soluble in water. Gas B: denser than air, insoluble in water. Gas C: less dense than air, soluble in water. Three collections of apparatus, P, Q and R, for collecting gases are shown.

Solids, liquids and gases

A student carries out electrolysis on two aqueous solutions using the apparatus illustrated.

Electrolysis

The reaction of magnesium with dilute hydrochloric acid is represented by the equation below. $\text{Mg}(s) + 2\text{HCl}(aq) \rightarrow \text{MgCl}_2(aq) + \text{H}_2(g)$ A student examines how the rate of this reaction changes at three different temperatures.

Rate of reaction

A student is given two bottles, A and B, together with some water. One bottle contains $1.00\,\text{g}$ of solid potassium chloride, $\text{KCl}$. The other bottle contains $1.00\,\text{g}$ of solid calcium chloride, $\text{CaCl}_2$. Dissolving potassium chloride in water is endothermic. Dissolving calcium chloride in water is exothermic. Devise experiments, using the dissolving of the solids in water, to determine which compound is in each bottle and which compound gives the larger heat change per gram of solid.

Experimental design

Solution K is dilute sulfuric acid, $\text{H}_2\text{SO}_4$. A student uses titration to find the concentration of solution K.

Acid–base titrations

A student receives aqueous copper(II) chloride, aqueous zinc sulfate, and an aqueous sample labelled X. The student then examines the three solutions.

Identification of ions and gases

When alcohols are burned, heat is given out. A student is investigating how much heat is released as different alcohols burn.

Fuels