Oct/Nov 2019

The concentration of aqueous sodium carbonate can be determined by its reaction with hydrochloric acid of known concentration. The indicator methyl orange is used. Which items of apparatus are needed?

Acid–base titrations

Determine the ratio between the number of molecules in $71\,\text{g}$ of gaseous chlorine and the number of molecules in $2\,\text{g}$ of gaseous hydrogen.

The mole and the Avogadro constant

The diagram illustrates an electrolysis experiment with inert electrodes. Which row indicates how the concentration of the electrolyte changes in L and in M as electrolysis continues?

Electrolysis

Molten sodium chloride is electrolysed. Which equation shows the reaction taking place at the cathode correctly?

Electrolysis

The diagram shows an energy profile. What does arrow R on the diagram indicate?

Exothermic and endothermic reactions

Which statement is correct about exothermic and endothermic reactions?

Exothermic and endothermic reactions

Gas P breaks down to produce gas Q. $x\text{P} \rightarrow y\text{Q}$ Two experiments are done to study the rate of reaction. All conditions are kept the same apart from the use of two different temperatures, $T_1$ and $T_2$. The outcomes are shown on graphs, each drawn using the same scale. Which row is correct?

Rate of reaction

In which reaction is the underlined substance undergoing reduction?

Redox

An industrial process is represented by the equation below. $\text{C}(s) + \text{H}_2\text{O}(g) \rightarrow \text{CO}(g) + \text{H}_2(g) \qquad \Delta H = +131\,\text{kJ mol}^{-1}$ Which row is the correct one?

Exothermic and endothermic reactions

Sodium hydroxide is introduced into a solution in order to change its pH. A neutral solution is produced. Which statement is correct?

The characteristic properties of acids and bases

Sodium chloride is dissolved in distilled water. Universal indicator is then added to the solution. What colour does the universal indicator show?

The characteristic properties of acids and bases

Which separation process is used in each of the following? 1 collecting copper(II) sulfate crystals from aqueous copper(II) sulfate 2 collecting ethanol from the fermentation of glucose 3 collecting nitrogen from liquid air

Separation and purification

Which statement concerning ammonia is correct?

The characteristic properties of acids and bases

Which statement explains why ammonium sulfate can be used as a fertiliser?

Fertilisers

Sulfuric acid is produced by the contact process. The equations for the reactions in the process are given. reaction 1: $\text{2SO}_2(g) + \text{O}_2(g) \rightleftharpoons \text{2SO}_3(g) \quad \Delta H = -198\,\text{kJ mol}^{-1}$ reaction 2: $\text{SO}_3(g) + \text{H}_2\text{O}(l) \rightarrow \text{H}_2\text{SO}_4(aq)$ Which of the statements below are true?

Reversible reactions and equilibrium

Three statements about the elements carbon, nitrogen and sulfur are given. Which of the statements are correct?

Elements, compounds and mixtures

What characteristic do halogens have?

Group VII properties

A section of the Periodic Table indicates where four elements are located. The symbols shown are not the elements’ true symbols. Which element has a high melting point and a variable oxidation state?

Transition elements

Brass is produced from copper and zinc. It has many uses. Brass is ............ and is made using these two elements. Brass is used in electrical plugs because it is an electrical ............ . Which pair of words fills gaps 1 and 2 correctly?

Alloys and their properties

Metal carbonates break down when heated. Which carbonate has the greatest thermal stability?

Reactivity series

Tin is a metal that lies in the reactivity series between iron and lead. Which method is used to extract tin from its ores?

Extraction of metals

Aluminium is obtained from aluminium oxide using electrolysis. Which statement about this electrolysis is correct?

Extraction of metals

In which reaction is a white precipitate present once the reaction has finished?

Identification of ions and gases

Methane and sulfur dioxide are two air pollutants present in the Earth’s atmosphere. Which row correctly gives one source of each gas?

Air quality and climate

The water supply is purified by filtration and chlorination. After these treatments, which substance is still present in the water supply?

Water

Which of the following statements are true about homologous series?

Formulae, functional groups and terminology

Alkanes are saturated compounds that contain only carbon and hydrogen. Structures 1, 2, 3 and 4 are saturated hydrocarbons. Among structures 1, 2, 3 and 4, which pair of structures are isomers?

Alkanes

When butene reacts with bromine, which compound could be produced?

Alkenes

Of the structural isomers with the formula $\text{C}_4\text{H}_{10}\text{O}$, how many are alcohols?

Formulae, functional groups and terminology

Which of these statements about the alcohol $\text{CH}_3\text{CH}_2\text{CH}_2\text{OH}$ are correct?

Alcohols

When propanoic acid reacts with calcium carbonate, the substances formed are calcium propanoate, carbon dioxide and water. What is the equation for this reaction?

Preparation of salts

When an acid reacts with an alcohol, an ester and water are formed. $\text{CH}_3\text{CH}_2\text{COOH} + \text{CH}_3\text{CH}_2\text{OH} \rightarrow \text{CH}_3\text{CH}_2\text{COOCH}_2\text{CH}_3 + \text{H}_2\text{O}$ State the name of the ester produced in this reaction?

Naming organic compounds

A segment of a polymer chain is shown. Which monomer was used to form this polymer?

Polymers

Which three elements are found as diatomic molecules at room temperature?

Elements, compounds and mixtures

Which of the following statements about polymers is correct?

Polymers

Sulfur dioxide is produced by warming sodium sulfite with hydrochloric acid. It is an acidic gas, and sulfur dioxide is denser than air. Which arrangement of apparatus would be appropriate for making and collecting a dry sample of sulfur dioxide?

Experimental design

Which diagram most accurately shows the structure of a solid metal?

Metallic bonding

Hydrogen sulfide reacts with an excess of oxygen as represented by the equation below. $2\text{H}_2\text{S}(g) + 3\text{O}_2(g) \rightarrow 2\text{H}_2\text{O}(g) + 2\text{SO}_2(g)$ A volume of $48\,\text{dm}^3$ of hydrogen sulfide is burned. What volume of sulfur dioxide will be produced at room temperature and pressure? [All volumes are measured under the same temperature and pressure conditions.]

The mole and the Avogadro constant

Which row correctly shows the different formulae for ethene and for its homologous series?

Alkenes

The Haber process is used to manufacture ammonia from nitrogen and hydrogen. $\text{N}_2(g) + 3\text{H}_2(g) \rightleftharpoons 2\text{NH}_3(g)$ What percentage yield is obtained when $60\,\text{kg}$ of ammonia is produced from $60\,\text{kg}$ of hydrogen?

The mole and the Avogadro constant

The concentration of aqueous sodium carbonate can be determined by reacting it with hydrochloric acid of known concentration. Methyl orange is the indicator used. Which items of equipment are required?

Acid–base titrations

What ratio compares the number of molecules present in 71 g of gaseous chlorine with the number of molecules present in 2 g of gaseous hydrogen?

The mole and the Avogadro constant

The diagram illustrates the apparatus used in an electrolysis experiment. From the apparatus shown, which electrolyte would produce colourless gases at both electrodes?

Electrolysis

Which metal is most likely to be obtained from its molten chloride through electrolysis?

Extraction of metals

Two energy profile diagrams are displayed. Both diagrams use the same scale on the y-axis. Which statement is correct?

Exothermic and endothermic reactions

Ammonium nitrate is dissolved in water. $\text{NH}_4\text{NO}_3(s) \xrightarrow{\text{H}_2\text{O}} \text{NH}_4\text{NO}_3(aq)$ $\Delta H = +25\,\text{kJ mol}^{-1}$ Which statements are correct?

Exothermic and endothermic reactions

Which of the following statements about photosynthesis is correct?

Exothermic and endothermic reactions

In which reaction does the underlined substance undergo reduction?

Redox

Catalysts can change how fast chemical reactions occur. Which statements correctly describe what happens when a catalyst is added to a reaction?

Rate of reaction

Solution T shows the following behaviour. 1 It reacts with magnesium to produce a gas. 2 It reacts with calcium carbonate to produce a gas. Which statement about solution T is correct?

The characteristic properties of acids and bases

Which substance has the property of being soluble in water?

Separation and purification

The diagrams illustrate three stages, 1, 2 and 3, in the making of a salt. Which row gives the correct solubilities of both the reactants and the salt produced in this preparation?

Preparation of salts

Which of the following statements about ammonia is correct?

The characteristic properties of acids and bases

A section of the Periodic Table is shown containing four elements, W, X, Y and Z. These are not the elements’ true symbols. Some of these pairs of elements may react to produce compounds. Which formulae are correct?

Formulae

The elements in Group I exhibit similar chemical properties. Which statement accounts for this?

Group I properties

Helium and xenon are both noble gases. Which statement is correct for both elements?

Noble gases

Metal X ions are mixed with aqueous potassium iodide. $2X^{2+}(aq) + 4I^{-}(aq) \rightarrow 2XI(s) + I_2(aq)$ (coloured) Using this information, it can be concluded that X is probably a .....1..... metal and the $X^{2+}(aq)$ ions are .....2..... . Which words best fill gaps 1 and 2?

Transition elements

Which of the substances is a metal?

Properties of metals

Which metal can be extracted from its oxide using either carbon or hydrogen?

Extraction of metals

Metal carbonates break down on heating. Which carbonate has the greatest thermal stability?

Arrangement of elements

Iron is obtained from its ore in a blast furnace. Coke and limestone are also put into the blast furnace. What is the role of the limestone?

Extraction of metals

Aluminium is obtained from aluminium oxide using electrolysis. Which of the following statements about this electrolysis is correct?

Extraction of metals

An atom’s nucleon number is usually larger than its proton number. The gap between these two values shows the number of ......1...... in the atom. Atoms with the same proton number but different nucleon numbers are known as ......2...... . Which words would correctly fill gaps 1 and 2?

Isotopes

Steel is made by passing oxygen through molten iron that contains impurities. A student gives two possible explanations for why this is done. 1. Some of the carbon in the impure iron is removed by the oxygen. 2. Iron(II) ions are oxidised to iron(III) ions by the oxygen. Which of these explanations are correct?

Extraction of metals

Z is a pollutant gas produced in internal combustion engines. When Z is dissolved in water, the resulting solution is acidic. In a catalytic converter, Z is removed from exhaust gases by reduction. What is the identity of Z?

Air quality and climate

A student carries out an investigation into the properties of a colourless organic liquid. Which observation indicates that the liquid is unsaturated?

Alkenes

Alkanes are saturated compounds that contain only carbon and hydrogen. Structures 1, 2, 3 and 4 are saturated hydrocarbons. Identify the pair of structures that are isomers.

Alkanes

When butene reacts with bromine, which compound might be formed?

Alkenes

Which statement concerning propene is correct?

Alkenes

Which term is used to describe the structure of Terylene?

Polymers

Which process is used to produce ethanol from ethene?

Alkenes

Which compound should be identified as an alcohol?

Alcohols

Which two compounds combine to produce $\text{CH}_3\text{CH}_2\text{COOCH}_3$?

Carboxylic acids

Which three elements are present as diatomic molecules at room temperature?

Elements, compounds and mixtures

Which compound could be suitable for flavouring a soft drink?

Formulae, functional groups and terminology

Which option is a pure compound?

Elements, compounds and mixtures

Which diagram most accurately shows the structure of a solid metal?

Metallic bonding

Hydrogen sulfide is burned in an excess of oxygen, as represented by the equation below. $2\text{H}_2\text{S}(g) + 3\text{O}_2(g) \rightarrow 2\text{H}_2\text{O}(g) + 2\text{SO}_2(g)$ $48\,\text{dm}^3$ of hydrogen sulfide is burned. What volume of sulfur dioxide will be produced at room temperature and pressure? [All volumes are measured at the same temperature and pressure.]

The mole and the Avogadro constant

Which statement about electrical conductivity is accurate?

Properties of metals

Ammonia is made from nitrogen and hydrogen using the Haber process. $\text{N}_2(g) + 3\text{H}_2(g) \rightleftharpoons 2\text{NH}_3(g)$ What percentage yield is obtained when $60\,\text{kg}$ of ammonia is produced from $60\,\text{kg}$ of hydrogen?

The mole and the Avogadro constant

The figure shows a section of the Periodic Table. It includes the element symbols Mg, V, Fe, Cu, Zn, B, C, Al, Si and P. Use only the elements displayed in the figure to answer the questions. Each element may be chosen once, more than once, or not used.

Arrangement of elements

Sodium is classed as a metal.

Properties of metals

Water may be separated from aqueous copper(II) sulfate by using distillation.

Separation and purification

This question concerns chlorine-containing compounds.

Acid–base titrations

The table presents some properties of four Group VII elements.

Group VII properties

Ethanoic acid, $\text{CH}_3\text{COOH}$, is classified as a weak acid.

The characteristic properties of acids and bases

Hydrogen may be formed when steam and carbon monoxide are passed over a catalyst. $\text{H}_2\text{O(g)} + \text{CO(g)} \rightleftharpoons \text{CO}_2\text{(g)} + \text{H}_2\text{(g)} \quad \Delta H = -41\,\text{kJ mol}^{-1}$

Reversible reactions and equilibrium

Silicon belongs to Group IV of the Periodic Table.

Giant covalent structures

This question concerns polymers.

Polymers

The diagram shows a section of the Periodic Table. The elements included are: B, C, N, O, F, He Al, Si, P, S, Cl, Ne Ga, Ge, As, Se, Br, Ar I, Xe Use only the elements displayed in the diagram to answer the questions. Each element can be chosen once, more than once, or not used at all.

Arrangement of elements

Magnesium is classed as a metal.

Ion and ionic bonds

Petroleum (crude oil) is a blend of hydrocarbons.

Fuels

This equation represents the reaction between calcium carbonate and hydrochloric acid. $\text{CaCO}_3(s) + 2\text{HCl}(aq) \rightarrow \text{CaCl}_2(aq) + \text{CO}_2(g) + \text{H}_2\text{O}(l)$

Rate of reaction

The table lists several properties for four Group I elements.

Group I properties

Butanoic acid, $\text{C}_3\text{H}_7\text{COOH}$, belongs to the carboxylic acid family.

Carboxylic acids

The Contact process is used to produce sulfuric acid. $2\text{SO}_2(g) + \text{O}_2(g) \rightleftharpoons 2\text{SO}_3(g) \quad \Delta H = -197\,\text{kJ mol}^{-1}$

Reversible reactions and equilibrium

Phosphorus is one of the elements in Group V of the Periodic Table.

Isotopes

Proteins are examples of natural polymers.

Polymers

A student carries out electrolysis on three solutions using the apparatus shown.

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 examines how the rate of this reaction changes at three different temperatures using the apparatus shown. In each trial, the student adds dilute hydrochloric acid to an excess of calcium carbonate. The volume of carbon dioxide in B is measured every 30 seconds.

Rate of reaction

Carbon and copper(II) oxide are each black solids. Copper(II) oxide reacts with dilute sulfuric acid to give an aqueous solution, whereas carbon neither reacts with nor dissolves in dilute sulfuric acid. In addition, neither carbon nor copper(II) oxide dissolve in water. The mixture contains only carbon and copper(II) oxide.

Separation and purification

A student is given three aqueous solutions: aqueous zinc sulfate, aqueous copper(II) sulfate and aqueous calcium nitrate. The student carries out tests on the three aqueous samples by adding each reagent shown in the table. Record the observations in the table. Write ‘no reaction’ where appropriate.

Identification of ions and gases

J is bleach. The student carries out an experiment to find the concentration of sodium chlorate(I), NaClO, in J.

Acid–base titrations

When zinc is placed into aqueous iron(II) sulfate, the temperature of the mixture rises. $\text{Zn}(s) + \text{FeSO}_4(aq) \rightarrow \text{ZnSO}_4(aq) + \text{Fe}(s)$

Exothermic and endothermic reactions

The properties of three gases, A, B and C, are given below. Diagrams of three apparatus arrangements, X, Y and Z, for collecting gases are also shown.

Solids, liquids and gases

Calcium carbonate reacts with dilute hydrochloric acid. $\text{CaCO}_3(s) + 2\text{HCl}(aq) \rightarrow \text{CaCl}_2(aq) + \text{CO}_2(g) + \text{H}_2\text{O}(l)$ Vigorous bubbling is observed. A student studies the rate of this reaction with three calcium carbonate samples, each having a different particle size. For every experiment the student adds all of the calcium carbonate, in excess, to dilute hydrochloric acid in apparatus E. The weighing bottle is put back on the balance. The mass is noted every 30 seconds. In experiment 1 the student uses large lumps of calcium carbonate.

Rate of reaction

One unlabelled bottle contains solid sodium carbonate, $\text{Na}_2\text{CO}_3$. A different unlabelled bottle contains solid sodium hydrogencarbonate, $\text{NaHCO}_3$. The reaction of sodium carbonate with dilute hydrochloric acid is exothermic. The reaction of sodium hydrogencarbonate with dilute hydrochloric acid is endothermic. Plan experiments based on the reaction of each solid with dilute hydrochloric acid: • to work out which solid is which • to decide which reaction gives the greater energy change per gram of solid. You may use any apparatus normally available in a chemistry laboratory, but no other chemicals. You should include every measurement you would take. Chemical equations are not needed.

Exothermic and endothermic reactions

A student is given solutions of: • aqueous chromium(III) nitrate • aqueous iron(II) chloride • aqueous iron(III) chloride The student carries out tests on the three aqueous solutions by adding each reagent listed in the table. Record the observations in the table. Write ‘no reaction’ where appropriate.

Identification of ions and gases

A student carries out an experiment to work out the percentage by mass of potassium iodate(V), $\text{KIO}_3$, in a specimen of impure potassium iodate(V). The impure potassium iodate(V) sample is put into a container that has already been weighed, and the container is weighed again. mass of container + impure potassium iodate(V) = $8.20\,\text{g}$ mass of empty container = $5.28\,\text{g}$

Acid–base titrations

A student sends an electric current through aqueous copper(II) sulfate electrolyte, using an inert anode and a copper cathode.

Electrolysis