Oct/Nov 2021

A student prepares aqueous copper(II) sulfate. The student pours copper(II) oxide powder into warm sulfuric acid in excess and mixes the contents by stirring. Which apparatus should be used to separate aqueous copper(II) sulfate from the extra copper(II) oxide?

Separation and purification

Which statement concerning the structure or bonding of metals is correct?

Metallic bonding

The relative atomic mass of chlorine is $35.5$. Determine the mass of $2.0\,\text{mol}$ of chlorine gas.

The mole and the Avogadro constant

Methane reacts with oxygen. $\text{CH}_4(\text{g}) + 2\text{O}_2(\text{g}) \rightarrow \text{CO}_2(\text{g}) + 2\text{H}_2\text{O}(\ell)$ $10\,\text{cm}^3$ of methane is mixed with $25\,\text{cm}^3$ of oxygen. What would be the total gas volume measured after the reaction? (Assume all volumes of gases are measured at room temperature and pressure.)

The mole and the Avogadro constant

An aqueous solution is prepared by dissolving $3.4\,\text{g}$ of sodium hydroxide, $\text{NaOH}$, and making the total volume up to $500\,\text{cm}^3$ of solution. What is the concentration, in $\text{mol dm}^{-3}$, of this sodium hydroxide solution?

The mole and the Avogadro constant

Which statement concerning electrolysis reactions is correct?

Electrolysis

The apparatus shown has been arranged to coat a steel key with copper by electroplating. No copper is deposited on the key. Which alteration is needed so that the key can be plated?

Electrolysis

Which process involves an endothermic change?

Exothermic and endothermic reactions

The reaction between hydrogen and chlorine that produces gaseous hydrogen chloride gives out heat. Which statement is correct?

Exothermic and endothermic reactions

The equation below represents the reaction used to produce ammonia. $\text{N}_2(\text{g}) + 3\text{H}_2(\text{g}) \rightleftharpoons 2\text{NH}_3(\text{g})$ Which change would reduce the activation energy for this reaction?

Rate of reaction

Which statements regarding oxidation and reduction are correct?

Redox

A student monitors the rate of reaction between marble chips, $\text{CaCO}_3$, and dilute hydrochloric acid. $\text{CaCO}_3 + 2\text{HCl} \rightarrow \text{CaCl}_2 + \text{CO}_2 + \text{H}_2\text{O}$ Which diagrams show the apparatus that is suitable for this experiment when used with a stopwatch?

Rate of reaction

Aqueous ammonium nitrite, $\text{NH}_4\text{NO}_2$, breaks down on heating. $\text{NH}_4\text{NO}_2(\text{aq}) \rightarrow \text{N}_2(\text{g}) + 2\text{H}_2\text{O}(\ell)$ For this salt, the anion is ......1...... . During the reaction, the nitrogen atoms in the ......2...... ion are oxidised. Which formulae correctly fill gaps 1 and 2?

Redox

The elements $X$ and $Y$ undergo a reversible reaction to produce $XY_2$. $X + 2Y \rightleftharpoons XY_2$ $1.0\,\text{mol}$ of $X$ is combined with $1.0\,\text{mol}$ of $Y$ and the mixture is allowed to react until equilibrium is established. Which of the following statements about this reaction are correct?

Reversible reactions and equilibrium

There are two solutions prepared. Solution P is $0.050\,\text{mol dm}^{-3}$ hydrochloric acid. Solution Q is $0.100\,\text{mol dm}^{-3}$ butanoic acid. A $2\,\text{cm}$ strip of magnesium ribbon is placed into $100\,\text{cm}^3$ of each solution. Effervescence is seen in both solutions, but it is quicker in solution P than it is in solution Q. Which statement best explains this observation?

The characteristic properties of acids and bases

Which compound can be prepared by precipitation?

Preparation of salts

In a neutralisation reaction, what particle change takes place?

The characteristic properties of acids and bases

To determine which nitrogenous fertiliser is superior, a student works out the percentage by mass of nitrogen in both ammonium sulfate and ammonium nitrate. Which row shows the correct answers?

Relative masses of atoms and molecules

The production of sulfuric acid using the Contact process requires three different raw materials. Of these raw materials, how many are elements, how many are compounds and how many are mixtures?

Elements, compounds and mixtures

The diagram illustrates a section of the Periodic Table. Which two letters show elements that are able to react with each other to make covalent compounds?

Simple molecules and covalent bonds

Which statement concerning elements in the Periodic Table is correct?

Arrangement of elements

Which statement concerning the properties of the elements in Group VIII of the Periodic Table, from helium to xenon, is correct?

Noble gases

A mixture containing three liquids is separated using fractional distillation. Which of the following statements are correct?

Separation and purification

Which two statements suggest that metal M may have a proton number between $21$ and $30$? 1 It is able to conduct electricity. 2 It does not react with water. 3 It produces two basic oxides with formulae $\text{MO}$ and $\text{M}_2\text{O}_3$. 4 It produces two coloured sulfates.

Transition elements

Different metals react with water in different ways. Which of the following statements is correct?

Reactivity series

Metal X is above zinc in the reactivity series but below sodium. Which method would be most suitable for extracting metal X from its ore?

Extraction of metals

Steel is frequently galvanised. Which of the following statements about galvanising are correct?

Corrosion of metals

During the extraction of aluminium from aluminium oxide, the three reactions below occur. 1 $\text{Al}^{3+} + 3e^- \rightarrow \text{Al}$ 2 $2\text{O}^{2-} \rightarrow \text{O}_2 + 4e^-$ 3 $\text{C} + \text{O}_2 \rightarrow \text{CO}_2$ Which reactions occur at the positive electrode?

Electrolysis

The carbon cycle controls how much carbon dioxide is present in the atmosphere. Combustion, photosynthesis and respiration all take part in this cycle. In what ways do these processes change the amount of carbon dioxide in the atmosphere?

Air quality and climate

Which statement concerning alkanes is correct?

Alkanes

The structure of compound X is displayed below. Four claims are given about compound X. 1 X burns in air, producing carbon dioxide and water. 2 X changes bromine water from colourless to brown. 3 X is propene. 4 Reacting X with hydrogen increases the number of $\text{C-C}$ single bonds. Which claims are correct?

Alkenes

What kind of reaction occurs when ethene reacts with steam to make ethanol?

Alkenes

Which compound could act as a flavouring agent in a non-alcoholic fruit drink?

Formulae, functional groups and terminology

A mixture containing four coloured dyes is examined using chromatography. The outcome is shown. Which alteration will make it possible to see the four dyes?

Chromatography

P is a polymer with these features: • each monomer used to make it contains six carbon atoms • it is not a polyester • it is produced by condensation polymerisation. What is the partial structure of P?

Polymers

When compound X is heated with an aqueous solution of compound Y, a gas is produced that turns red litmus blue. Which statements are correct?

Identification of ions and gases

Aqueous zinc chloride is examined by adding reagents. Which observation is correct?

Identification of ions and gases

The diffusion rates of carbon dioxide and methane are compared at two temperatures, one high and one low. Which row correctly identifies the gas that diffuses more quickly and the temperature at which diffusion occurs most rapidly?

Diffusion

Which statement concerning atoms and ions is correct?

Ion and ionic bonds

The bonding in a carbon dioxide molecule may be shown using a dot-and-cross diagram. Which diagram is the correct one?

Simple molecules and covalent bonds

During a titration, $25.0\,\text{cm}^3$ of aqueous sodium hydroxide is placed in a conical flask. Several drops of indicator are then introduced. Dilute hydrochloric acid is afterwards added to the flask until the end-point is reached. Which apparatus pieces are used to measure volume in this experiment?

Acid–base titrations

Which statement concerning the structure or bonding of metals is correct?

Metallic bonding

If chlorine has a relative atomic mass of $35.5$, what is the mass of $2.0\,\text{mol}$ of chlorine gas?

The mole and the Avogadro constant

During a reaction involving gases, the combined volume of the gaseous reactants can be different from the combined volume of the gaseous products. Which reaction gives the largest percentage change in gas volume? (Assume each reaction goes to completion.)

Solids, liquids and gases

Dilute hydrochloric acid reacts with sodium carbonate. $\text{Na}_2\text{CO}_3 + 2\text{HCl} \rightarrow 2\text{NaCl} + \text{H}_2\text{O} + \text{CO}_2$. A sample that contains $0.0800\,\text{mol}$ of sodium carbonate is placed into a solution that contains $0.100\,\text{mol}$ of hydrochloric acid. Which volume of carbon dioxide is formed, measured at room temperature and pressure?

The mole and the Avogadro constant

Which statement concerning the electrolysis of solutions is correct?

Electrolysis

The apparatus shown has been arranged to plate a steel key with copper, but the key does not become coated with copper. Which change is needed in order to plate the key?

Electrolysis

The equation represents the reaction between glucose and oxygen. $\text{C}_6\text{H}_{12}\text{O}_6 + 6\text{O}_2 \rightarrow 6\text{CO}_2 + 6\text{H}_2\text{O}$. Which statement regarding this reaction is correct?

Redox

The energy profile diagram for a chemical reaction is shown. Which statement is correct?

Exothermic and endothermic reactions

The equation represents the reaction used to make ammonia. $\text{N}_2(g) + 3\text{H}_2(g) \rightleftharpoons 2\text{NH}_3(g)$. Which change will reduce the activation energy of the reaction?

Rate of reaction

The apparatus is used to monitor the rate of reaction between magnesium carbonate, $\text{MgCO}_3$, and dilute nitric acid, $\text{HNO}_3$. $\text{MgCO}_3(s) + 2\text{HNO}_3(aq) \rightarrow \text{Mg(NO}_3)_2(aq) + \text{H}_2\text{O}(l) + \text{CO}_2(g)$ The graph plots the volume of gas collected against time. Three claims are given about the experiment. 1. The mass of the flask and its contents falls as time passes. 2. The reaction rate falls as time passes. 3. The reaction has ended after four minutes. Which statements are correct?

Rate of reaction

A student monitors the rate of the reaction between marble chips, $\text{CaCO}_3$, and dilute hydrochloric acid. $\text{CaCO}_3 + 2\text{HCl} \rightarrow \text{CaCl}_2 + \text{CO}_2 + \text{H}_2\text{O}$ Which diagrams show apparatus that, together with a stopwatch, are suitable for this experiment?

Rate of reaction

Aqueous bromine is mixed with aqueous sodium chloride. Which statement is correct?

Group VII properties

Which statement is true for every reversible reaction that has reached dynamic equilibrium?

Reversible reactions and equilibrium

Which of the following statements about acids and bases is correct?

The characteristic properties of acids and bases

Which compound can be produced by precipitation?

Preparation of salts

Which methods can be used to prepare a pure sample of copper(II) sulfate? 1. acid reacting with a metal carbonate 2. acid reacting with a metal oxide 3. acid reacting with a metal 4. precipitation method

Preparation of salts

Ammonia is produced through a reversible reaction. $\text{N}_2(g) + 3\text{H}_2(g) \rightleftharpoons 2\text{NH}_3(g)$\qquad $\Delta H = -92\,\text{kJ mol}^{-1}$ A chemist studies how the percentage of ammonia present at equilibrium varies as pressure changes. The investigation is done at both $250^\circ\text{C}$ and at $350^\circ\text{C}$. Which graph represents the chemist’s results?

Reversible reactions and equilibrium

Which of the following statements about sulfur dioxide, $\text{SO}_2$, is correct?

Oxides

The diagram illustrates a section of the Periodic Table. Which two letters show elements that can react with each other to make covalent compounds?

Simple molecules and covalent bonds

Which of the following statements about some elements in the Periodic Table is correct?

Arrangement of elements

The following statements concern the halogens. 1. Every halogen is a non-metallic, diatomic molecule. 2. Chlorine can displace both bromine and iodine from aqueous solutions of their salts. 3. As Group VII of the Periodic Table is descended, the halogens become more reactive. Which of these statements are correct?

Group VII properties

A large number of industries need pure oxygen. How is pure oxygen obtained in large quantities for these purposes?

Separation and purification

Which two statements show that metal M could have a proton number between 21 and 30? 1. It is able to conduct electricity. 2. It does not undergo reaction with water. 3. It produces two basic oxides with formulae $\text{MO}$ and $\text{M}_2\text{O}_3$. 4. It produces two coloured sulfates.

Transition elements

The table shows the properties of four metals, P, Q, R and S. Which statement is correct?

Properties of metals

Which of the following statements about extracting metals from their ores are correct?

Extraction of metals

Which statements concerning the corrosion of iron are correct?

Corrosion of metals

During the extraction of aluminium from aluminium oxide, these three reactions occur. 1 $\text{Al}^{3+} + 3e^- \rightarrow \text{Al}$ 2 $2\text{O}^{2-} \rightarrow \text{O}_2 + 4e^-$ 3 $\text{C} + \text{O}_2 \rightarrow \text{CO}_2$ Which of these reactions occur at the positive electrode?

Electrolysis

Which of the following statements are correct?

Elements, compounds and mixtures

The two isomers are shown below. Which statements about these isomers are true?

Formulae, functional groups and terminology

A hydrocarbon compound Q has the molecular formula $\text{C}_x\text{H}_y$. Q reacts with hydrogen to give one product whose molecular formula is $\text{C}_x\text{H}_{y+2}$. Which statement about Q is correct?

Alkenes

Which structural formula shows an alcohol?

Formulae, functional groups and terminology

Which statement concerning carboxylic acids is correct?

Carboxylic acids

An impure specimen of compound X has a melting point of $120\,^{\circ}\text{C}$. X is then purified, and its melting point is measured once more. Which row is the correct one?

Separation and purification

P is a polymer with the following properties: • each monomer used to make it contains six carbon atoms • it is not a polyester • it is produced by condensation polymerisation. State the partial structure of P.

Polymers

A red-brown precipitate appears when aqueous sodium hydroxide is mixed with aqueous compound X. A white precipitate appears when dilute nitric acid is added first, followed by aqueous barium nitrate, to aqueous compound X. What is the identity of X?

Identification of ions and gases

An aqueous solution containing zinc chloride is tested by adding reagents. Which observation is the correct one?

Identification of ions and gases

A gas sample is let out from a fixed location in a laboratory. A detector is positioned ten metres away from the release point. It measures and notes the time at which the gas concentration reaches ten molecules per million molecules of air. The investigation is done using two gases at different temperatures. In which experiment was the time shown by the detector the largest?

Diffusion

The table presents data for several particles. What are the values of W, X and Y?

Atomic structure and the Periodic Table

A covalent compound P has the empirical formula $\text{CH}_2\text{O}$. Which structure is P represented by?

Formulae, functional groups and terminology

Choose your answers from the oxides listed below. aluminium oxide calcium oxide iron(II) oxide magnesium oxide silicon dioxide sodium oxide sulfur dioxide Each oxide may be selected once, selected more than once, or not selected at all. State which oxide:

Oxides

The table gives some properties of the Group IV elements. Predict the density of tin.

Arrangement of elements

Dry air is made up of nitrogen, oxygen, noble gases and carbon dioxide.

Air quality and climate

A sample of iron powder undergoes reaction with dilute sulfuric acid. $\text{Fe}(s) + \text{H}_2\text{SO}_4(aq) \rightarrow \text{FeSO}_4(aq) + \text{H}_2(g)$

Rate of reaction

Alkenes belong to a homologous series of hydrocarbons.

Alkenes

Magnesium is oxidised when it reacts with aqueous silver nitrate. $\text{Mg} + 2\text{Ag}^+ \rightarrow \text{Mg}^{2+} + 2\text{Ag}$

Redox

Phosphorus reacts with chlorine to produce phosphorus(III) chloride. $3\text{Cl}_2 + 2\text{P} \rightarrow 2\text{PCl}_3$ This reaction gives out heat.

Group VII properties

Silver is a transition element. Potassium is a Group I metal in the Periodic Table. State two differences between the physical properties of silver and potassium.

Group I properties

The structural formula for angelic acid is displayed.

Carboxylic acids

State where the hydrogen and nitrogen used to manufacture ammonia by the Haber process come from.

Fertilisers

Select the answer to each question from the chlorides listed below. aluminium chloride ammonium chloride cobalt(II) chloride hydrogen chloride iron(III) chloride potassium chloride silver chloride sodium chloride You may use any chloride once, more than once, or not at all. State which chloride:

Ion and ionic bonds

This question concerns the elements in Group V of the Periodic Table.

Arrangement of elements

This question concerns pollutant gases.

Air quality and climate

Magnesium ribbon is made to react with dilute hydrochloric acid. $\text{Mg(s)} + 2\text{HCl(aq)} \rightarrow \text{MgCl}_2\text{(aq)} + \text{H}_2\text{(g)}$ The graph indicates the volume of hydrogen gas obtained at $20\degree\text{C}$ as the reaction continues. Magnesium is in excess. The experiment is carried out again with a lower concentration of hydrochloric acid. The volume of acid used and every other condition stay the same.

Rate of reaction

Alkanes form a homologous series of hydrocarbons. As the number of carbon atoms goes up, the boiling point, melting point and density of alkanes also rise.

Alkanes

Lithium is reacted with aqueous zinc iodide. $2\text{Li} + \text{ZnI}_2 \rightarrow 2\text{LiI} + \text{Zn}$

Group VII properties

Phosphorus reacts with hydrogen to make phosphine, $\text{PH}_3$. $2\text{P} + 3\text{H}_2 \rightarrow 2\text{PH}_3$ It is endothermic.

Exothermic and endothermic reactions

Sodium is a Group I metal in the Periodic Table. Diamond (carbon) is a non-metal and it conducts heat well.

Reversible reactions and equilibrium

The diagram shows the structure of organic compound T.

Alkenes

This question focuses on sulfuric acid and sulfates.

Preparation of salts

A student uses the apparatus to produce ethanoic acid from ethanol.

Experimental design

A student examines the reaction between calcium carbonate and hydrochloric acid. The reaction is represented by the equation: $\text{CaCO}_3(s) + 2\text{HCl}(aq) \rightarrow \text{CaCl}_2(aq) + \text{CO}_2(g) + \text{H}_2\text{O}(l)$. The student carries out an investigation to find how the rate of this reaction changes when the concentration of hydrochloric acid is altered. Method: The student measures $100\,\text{cm}^3$ of $1.0\,\text{mol dm}^{-3}$ hydrochloric acid and pours it into a beaker, adds a known mass of calcium carbonate, starts a clock immediately, stops the clock when all of the calcium carbonate has reacted and records the reaction time. The experiment is repeated using different concentrations of hydrochloric acid. Water is added so that the total volume is the same in every experiment. All other variables are kept constant.

Rate of reaction

The student is given three unlabelled bottles containing dilute sulfuric acid, aqueous calcium chloride and aqueous zinc chloride. In addition, the student has dilute nitric acid, aqueous barium nitrate and aqueous sodium hydroxide, with no other chemicals or indicators supplied.

Identification of ions and gases

A student works out the percentage by mass of iron present in a sample of impure iron.

Acid–base titrations

The solid R is composed of two cations and one anion.

Identification of ions and gases

The reaction of aqueous lead(II) nitrate with aqueous potassium iodide forms lead(II) iodide: $\text{Pb(NO}_3)_2(aq) + 2\text{KI}(aq) \rightarrow \text{PbI}_2(s) + 2\text{KNO}_3(aq)$. Solution G contains $1.0\,\text{mol dm}^{-3}$ KI(aq). Solution H is Pb(NO$_3$)$_2$(aq) with an unknown concentration.

The mole and the Avogadro constant

The apparatus is used by a student to separate a mixture containing three alkanes.

Alkanes

A student carries out an investigation into the reaction of zinc with dilute sulfuric acid. The reaction equation is: $\text{Zn(s)} + \text{H}_2\text{SO}_4\text{(aq)} \rightarrow \text{ZnSO}_4\text{(aq)} + \text{H}_2\text{(g)}$

Rate of reaction

A student has three unlabelled bottles, and each one contains a solution. The student is told that the bottles contain: • dilute hydrochloric acid • aqueous aluminium sulfate • aqueous zinc sulfate The student is given: • dilute nitric acid • aqueous silver nitrate • aqueous ammonia and no other chemicals or indicators.

Identification of ions and gases

The mixture is a solid made from iron(II) sulfate and sand. A student finds the percentage by mass of iron(II) sulfate in this mixture.

Acid–base titrations

A solid S has two cations and one anion. Complete the table. Name any gases produced in the tests.

Identification of ions and gases

When dilute sulfuric acid receives aqueous sodium hydroxide, the reaction takes place. $2\text{NaOH(aq)} + \text{H}_2\text{SO}_4\text{(aq)} \rightarrow \text{Na}_2\text{SO}_4\text{(aq)} + 2\text{H}_2\text{O(l)}$

Acid–base titrations