May/June 2024

The boiling point of sodium is $890\,^{\circ}\text{C}$. What occurs to sodium atoms as the temperature of a sodium sample falls from $950\,^{\circ}\text{C}$ to $900\,^{\circ}\text{C}$?

Solids, liquids and gases

Dilute sulfuric acid and lead(II) bromide are electrolysed separately. Which statements are right?

Electrolysis

Which statements about a hydrogen-oxygen fuel cell are correct?

Hydrogen–oxygen fuel cells

Which row shows what occurs in an endothermic reaction?

Exothermic and endothermic reactions

Which diagram indicates a chemical change?

Physical and chemical changes

The diagram shows a way to study how the rate of reaction between calcium carbonate and dilute hydrochloric acid changes under different conditions. • Put $50\,\text{cm}^3$ of dilute hydrochloric acid into a conical flask. • Pour a measured volume of water into the conical flask. • Warm the conical flask to the stated temperature. • Add $1.0\,\text{g}$ of calcium carbonate to the conical flask. • Record how long the reaction takes to complete. Which volume of water and which temperature result in the shortest time for the reaction to finish?

Rate of reaction

The reaction rate for magnesium reacting with hydrochloric acid is being investigated. The overall volume of hydrogen produced is recorded at various times. A graph showing the results is displayed. Which conclusions are correct?

Rate of reaction

Water is mixed with anhydrous copper(II) sulfate. Which row shows the direction of energy change and the colour change of the mixture as the reaction takes place?

Exothermic and endothermic reactions

Which chemical equation represents an oxidation reaction?

Redox

A farmer applies calcium hydroxide to a field in order to reduce its acidity. If ammonium nitrate fertiliser is then added to the field straight away after the calcium hydroxide, the two substances react. Why does this reaction reduce the fertiliser’s effectiveness?

The characteristic properties of acids and bases

Which statement concerning sodium oxide or nitrogen dioxide is correct?

Oxides

Which row shows the conditions under which gas particles collide most often?

Solids, liquids and gases

A titration method is used to make a pure soluble sulfate salt from dilute sulfuric acid. What other reagent is needed?

Preparation of salts

Which row concerning elements in the Periodic Table is correct?

Arrangement of elements

The table shows some data about three elements in Group I of the Periodic Table. Which row gives the melting point and density of rubidium?

Group I properties

Which statement gives the description of a transition element?

Transition elements

The electronic configurations of helium, neon and argon are displayed. Which row identifies these gases?

Noble gases

X is a lustrous, silver-coloured solid under room temperature and pressure conditions. X also conducts heat and electricity well in the solid state. Which statement about X is correct?

Properties of metals

Which elements can be joined to form an alloy?

Alloys and their properties

Three metals, L, M and N, are each added on their own to dilute hydrochloric acid and cold water. The outcomes are shown. What is the reactivity order of the metals?

Reactivity series

Which chemical reaction generates carbon dioxide?

Preparation of salts

An air sample made up of only four gases is analysed. Which row gives the percentage composition of the air sample?

Air quality and climate

The diagram illustrates several properties of particles in an atom. Which labelled part of the diagram do electrons belong to?

Atomic structure and the Periodic Table

Which substance contains two of the elements present in NPK fertilisers?

Elements, compounds and mixtures

Which statement concerning sulfur is correct?

Elements, compounds and mixtures

Name two harmful impacts of particulates in the air.

Air quality and climate

Which formula shows a compound belonging to the homologous series of alkanes?

Alkanes

Which of the following statements about ethane is correct?

Alkanes

What raw material is used to produce ethanol by fermentation?

Alcohols

Which statement regarding ethanoic acid is correct?

Carboxylic acids

Which statement gives the reason that disposing of plastic waste causes environmental problems?

Polymers

Substance X together with four known substances, P, Q, R and S, is tested using chromatography. The chromatogram obtained is shown. Which statement about X is correct?

Chromatography

Copper does not dissolve in water. Copper(II) oxide is a solid that will not dissolve in water, but it does react with dilute hydrochloric acid. Which method is used to separate copper from a mixture containing copper and copper(II) oxide?

Separation and purification

Certain properties of substances W, X, Y and Z are displayed. Which of these substances are ionic?

Ions and ionic bonds

A salt, S, is added to water and the resulting solution is tested in three ways. What is the identity of S?

Identification of ions and gases

An atom may become an ion by either losing electrons or gaining electrons. Which row is correct?

Ions and ionic bonds

A covalent molecule, M, has four shared pairs of electrons. What is the identity of M?

Simple molecules and covalent bonds

Which substance is characterised by a giant covalent structure?

Giant covalent structures

Iron(III) oxide is reduced by carbon monoxide to form iron and carbon dioxide. What balanced equation represents this reaction?

Redox

The equation for the reaction of magnesium with dilute hydrochloric acid is shown here: $\text{Mg} + 2\text{HCl} \rightarrow \text{MgCl}_2 + \text{H}_2$. What mass of magnesium chloride is produced when $48.0\,\text{g}$ of magnesium reacts completely with excess dilute hydrochloric acid?

The mole and the Avogadro constant

Which statement about gases is true?

Solids, liquids and gases

Which row gives the correct formulae for lead(II) bromide and butane?

Formulae

Calcium phosphate is produced when solutions of calcium chloride and sodium phosphate are mixed together. $x\,\text{CaCl}_2 + y\,\text{Na}_3\text{PO}_4 \rightarrow 2\text{Ca}_3(\text{PO}_4)_2 + 12\text{NaCl}$. What are the values of $x$ and $y$ that balance the equation?

Formulae

What does relative molecular mass, $M_r$, mean?

Relative masses of atoms and molecules

During an experiment, electricity is used to decompose a molten compound. Which row gives the negative electrode and the general term for the molten compound undergoing decomposition?

Electrolysis

Hydrogen-oxygen fuel cells can be used to supply power for vehicles. What is generated by the fuel cells?

Hydrogen–oxygen fuel cells

Three reactions are given. Which of the reactions are endothermic?

Exothermic and endothermic reactions

Which process results in a physical change?

Physical and chemical changes

A fixed mass of gaseous ammonia and an excess of gaseous hydrogen chloride are allowed to react to form solid ammonium chloride. Line X shows how the total mass of ammonium chloride made changes with time. The reaction is carried out again at a higher pressure. Every other condition is unchanged. Line Y shows how the total mass of ammonium chloride made changes with time at the higher pressure. Which diagram is correct?

Rate of reaction

The reaction equation for the hydration of anhydrous copper(II) sulfate is given below. $\text{CuSO}_4 + 5\text{H}_2\text{O} \rightarrow \text{CuSO}_4\cdot5\text{H}_2\text{O}$ What colour change is seen in this reaction?

Elements, compounds and mixtures

In which of the reactions is the underlined substance reduced?

Redox

A sample of argon gas is warmed in a sealed container. Which row shows what happens to the pressure and the size of the argon atoms?

Solids, liquids and gases

Four separate solutions are each checked using blue litmus and methyl orange. It is already known that every solution is either acidic or alkaline. The outcomes are given below. Solution 1: blue litmus - red; methyl orange - red Solution 2: blue litmus - red; methyl orange - yellow Solution 3: blue litmus - blue; methyl orange - yellow Solution 4: blue litmus - blue; methyl orange - yellow Which statement is correct?

The characteristic properties of acids and bases

Which of the following statements about sulfur dioxide or calcium oxide is correct?

Oxides

What substances may be used to produce pure crystals of sodium sulfate?

Separation and purification

Which statements describe the changes that take place from left to right across a period of the Periodic Table?

Arrangement of elements

A section of the Periodic Table is displayed. Which element is the non-metal with the highest reactivity?

Group VII properties

An alloy is made up of aluminium, copper, magnesium, manganese, silver and zirconium. Which row states the number of transition elements present in the alloy and how the density of the transition elements compares with that of sodium?

Transition elements

Which statement concerning the halogens and their compounds is correct?

Group VII properties

Which row shows an element from Group VIII of the Periodic Table?

Arrangement of elements

Magnesium reacts with dilute hydrochloric acid. Which gas is released in this reaction?

The characteristic properties of acids and bases

Which of these statements about aluminium is correct?

Properties of metals

Which statement is accurate?

Elements, compounds and mixtures

Which statement indicates that a liquid is pure water?

Elements, compounds and mixtures

Which compound can be mixed with ammonium sulfate to produce an NPK fertiliser?

Fertilisers

Four gases present in air are listed below. Which of them cause global warming directly when their concentrations increase?

Air quality and climate

The structures for four organic compounds are given. Which of the compounds are members of the same homologous series?

Formulae, functional groups and terminology

Which statements about propene are correct?

Alkenes

Petroleum is a mixture. Which method is used to separate petroleum into its constituent substances?

Separation and purification

An equation for a reaction that makes ethanol is given: ethene + steam $\rightarrow$ ethanol. Which type of reaction does the equation represent?

Alkenes

Four statements concerning ethene or poly(ethene) are given. Which of the statements are correct?

Alkenes

Dissolved sodium chloride is present in sea water. Which method is used to obtain pure water from it?

Separation and purification

Which item of apparatus is used to measure out exactly $21.4\,\text{cm}^3$ of water?

Experimental design

Which row shows methods used to test the purity of a compound?

Separation and purification

An aqueous solution of compound M is examined. The observations are as follows: the flame test gives a lilac colour; adding acidified barium nitrate produces a white precipitate. What compound is M?

Identification of ions and gases

Which row gives the counts of protons, neutrons and electrons in the ion $^{{18}}_{{8}}\text{O}^{2-}$?

Isotopes

Isotopes of a single element have some characteristics that are alike and some that are unlike. Which row shows the characteristics that are alike and the ones that are unlike?

Isotopes

Shown are the electronic configurations of four atoms, W, X, Y and Z. Which one of these atoms produces an ion with a charge of $2-$ on reaction?

Ions and ionic bonds

Which of the following statements about bonding is correct?

Simple molecules and covalent bonds

Which statement about diamond is correct?

Giant covalent structures

Which two processes are needed to turn ice into steam?

Solids, liquids and gases

A compound, $\text{CH}_3\text{Cl}$, is given with three statements. Which of the statements are correct?

Simple molecules and covalent bonds

Iron water taps are often electroplated with a chromium coating. Which statements give reasons why iron water taps are electroplated?

Corrosion of metals

Molten caesium bromide is electrolysed with inert electrodes. Which row gives the product formed at each electrode?

Electrolysis

Which equation shows the overall reaction taking place in a hydrogen-oxygen fuel cell?

Hydrogen–oxygen fuel cells

Which statements about endothermic reactions are correct?

Exothermic and endothermic reactions

Which process counts as a physical change?

Physical and chemical changes

Magnesium reacts with dilute hydrochloric acid, $\text{HCl}$, to form hydrogen gas. Which row shows the reaction conditions that result in the fastest reaction rate?

Rate of reaction

Which reaction results in the formation of a white-coloured substance?

Identification of ions and gases

In a blast furnace, iron is obtained when iron(III) oxide reacts with carbon monoxide. The reaction is given below. $\text{Fe}_2\text{O}_3 + 3\text{CO} \rightarrow 2\text{Fe} + 3\text{CO}_2$ Which substance undergoes oxidation, and which substance undergoes reduction in this reaction?

Redox

Which row gives the colours of litmus and methyl orange in acidic or alkaline solutions?

The characteristic properties of acids and bases

Which row shows how a gas’s volume alters when the temperature rises, or when the pressure rises?

Solids, liquids and gases

Aqueous sodium hydroxide is allowed to react with excess dilute hydrochloric acid. Which ion is responsible for the acidity of the final mixture?

The characteristic properties of acids and bases

Universal indicator is added to an aqueous solution of oxide $X$. The indicator undergoes a colour change from green to red. What is $X$?

Oxides

Which rows show two aqueous salts that react together to form a precipitate?

Ions and ionic bonds

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

Arrangement of elements

Each of the four mixtures contains a halogen and an aqueous sodium halide. Which row shows what happens in the mixtures illustrated?

Group VII properties

Which row shows a transition element?

Transition elements

Which of the following statements about how metals are used is correct?

Uses of metals

Which statements show why stainless steel is chosen for cutlery?

Alloys and their properties

Four distinct metals are each reacted with the same volume of dilute hydrochloric acid. The table gives the effervescence rate for every metal. What is the reactivity order of the four metals, beginning with the most reactive?

Reactivity series

Which of the following statements about the rusting of iron is correct?

Corrosion of metals

A mixture includes four substances: calcium nitrate, iron(II) sulfate, oxygen, and water. Which statement best describes the mixture?

Elements, compounds and mixtures

Water is taken from a river to supply households with water. Some domestic-water treatments are listed below: chlorination; sedimentation and filtration; treatment with carbon. Which statement about these treatments is correct?

Water

A farmer is aware that his soil requires phosphorus and potassium. He can choose from four fertilisers: 1 $\text{NH}_4\text{NO}_3$; 2 $(\text{NH}_4)_3\text{PO}_4$; 3 $\text{KNO}_3$; 4 $(\text{NH}_2)_2\text{CO}$. Which fertilisers ought he to use?

Fertilisers

Which strategies help to reduce the formation of acid rain?

Air quality and climate

The structures of four organic compounds, W, X, Y and Z, are shown. Which of these compounds belong to the same homologous series?

Formulae, functional groups and terminology

Which molecular formula corresponds to an alkene?

Alkenes

Which row names the petroleum fractions used to cut down friction between metal parts in engines and to act as a fuel in cars?

Fuels

The following four fuels are given: 1 ethanol; 2 coal; 3 hydrogen; 4 natural gas. Which of these fuels are fossil fuels?

Fuels

Bromine water is placed into two test-tubes. Extra hexene is then put into the first test-tube. Extra hexane is then put into the second test-tube. Which row shows the observation for each test-tube?

Alkenes

The displayed structure of compound G is shown. G belongs to the same homologous series as ethanoic acid. Which row gives a description of an aqueous solution of G?

The characteristic properties of acids and bases

When zinc is added to dilute sulfuric acid, hydrogen gas is released. Which apparatus is required to examine how temperature changes affect the rate of this reaction? 1 thermometer 2 stop-watch 3 volumetric pipette 4 gas syringe

Rate of reaction

An ion is shown by the symbol $^{18}_{8}\text{O}^{2-}$. Which of the following statements about this ion are correct?

Atomic structure and the Periodic Table

Two tests are performed on substance Z. test 1 When a flame test is done, a red flame is seen. test 2 Substance Z is dissolved in water, then dilute nitric acid is added, followed by aqueous silver nitrate. A yellow precipitate is formed. What is substance Z?

Identification of ions and gases

What does the term nucleon number mean?

Atomic structure and the Periodic Table

Which row shows the electrical conductivity of covalent compounds and ionic compounds in the solid state and when molten?

Ions and ionic bonds

Which statement about the bonding in sodium chloride is correct?

Ions and ionic bonds

The diagram represents how carbon atoms are arranged in a giant covalent structure. Which row identifies the substance and states a use for it?

Giant covalent structures

Which statement gives the correct definition of molecular formula?

Formulae