May/June 2023

The diagram illustrates what happens when a purple crystal is placed into water. Which processes occur in this experiment?

Diffusion

Which statement concerning hydrogen fuel cells is correct?

Hydrogen–oxygen fuel cells

A reaction pathway diagram is given. Which statement about this reaction is correct?

Exothermic and endothermic reactions

Pieces of calcium carbonate react with dilute hydrochloric acid, as shown. $\text{CaCO}_3 + 2\text{HCl} \rightarrow \text{CaCl}_2 + \text{H}_2\text{O} + \text{CO}_2$ Which change in the conditions would lower the rate of the reaction?

Rate of reaction

Solid copper(II) sulfate can be found in two forms, anhydrous and hydrated. One of these forms is blue, whereas the other is white. The change between the two forms can be reversed. blue form $\rightleftharpoons$ white form Which form is the blue form, and by what method is the change from the blue form to the white form caused?

Physical and chemical changes

Four redox equations, plus statements about them, are presented. Which of these statements about the equations are correct?

Redox

Sodium hydroxide produces an alkaline solution with a pH of $14$. Which indicator changes to yellow when it is added to this solution?

The characteristic properties of acids and bases

Which row correctly identifies an acidic oxide and a basic oxide?

Oxides

A student prepares aqueous copper(II) chloride by adding excess copper(II) carbonate to dilute hydrochloric acid. What is the next step in the method for producing solid copper(II) chloride?

Preparation of salts

Which of the following statements about trends within a period of the Periodic Table are correct?

Arrangement of elements

Which row indicates the pattern for melting point, density and reactivity as Group I is descended?

Group I properties

Which row concerning elements, mixtures and compounds is correct?

Elements, compounds and mixtures

Which row states a similarity and a difference between chlorine and bromine?

Group VII properties

Which statement gives a description of transition elements?

Transition elements

Which diagram represents the electronic structure of a noble gas?

Atomic structure and the Periodic Table

What gas forms when powdered zinc is added to dilute hydrochloric acid?

The characteristic properties of acids and bases

Which metal is chosen for aircraft manufacture because of its low density?

Uses of metals

The diagram illustrates the structure of a solid. Which solids are shown in the diagram?

Solids, liquids and gases

Three students, X, Y and Z, are informed that solid P reacts with dilute acids and also carries electric current. The table below gives the students’ ideas about what P could be. X: copper Y: iron Z: graphite Which students are correct?

Properties of metals

Which substances present in air are required for iron to rust?

Corrosion of metals

A portion of the reactivity series of metals is shown. metal P carbon metal Q metal R (decreasing reactivity) Which row indicates the method used to extract each metal from its ore?

Extraction of metals

A number of processes are carried out to treat domestic water. Which row identifies a reason for the process shown?

Water

State the electron’s relative charge and relative mass.

Atomic structure and the Periodic Table

Which two compounds are used to produce an NPK fertiliser?

Fertilisers

Some details about gas X are given below. • It does not occur in clean, dry air. • It does not cause respiratory problems. • It contributes to global warming. What is X?

Air quality and climate

A section of the structure of a vitamin A molecule is shown. Which statements about this section of the structure are correct?

Formulae, functional groups and terminology

The fractional distillation of petroleum is illustrated. Which fraction is composed of hydrocarbons with the longest chain length?

Fuels

Which equation illustrates the cracking of an alkane?

Alkanes

Which of the following statements about ethanol are correct?

Alcohols

Which substances will react with aqueous ethanoic acid and give a gas?

The characteristic properties of acids and bases

In reaction R, $2000$ molecules of $\text{CH}_2{=}\text{CH}_2$ combine to produce only one molecule X. $2000\ \text{CH}_2{=}\text{CH}_2 \rightarrow X$ Which terms are used to describe reaction R, $\text{CH}_2{=}\text{CH}_2$ and X?

Polymers

The concentration of acids and alkalis may be found by titration. What apparatus is required to carry out a titration?

Acid–base titrations

Which process is used to make drinking water from sea water?

Water

The atomic structures of four particles, W, X, Y and Z, are shown below. Which of these particles are isotopes of the same element?

Isotopes

Two separate tests were carried out on a white solid sample X. Test: dilute nitric acid is added Observation: fizzing occurs Test: aqueous sodium hydroxide is added and the mixture is warmed Observation: a gas is produced which turns damp red litmus paper blue What substance is X?

Identification of ions and gases

Which row indicates the properties of an ionic compound?

Ions and ionic bonds

Which row explains the formation of single covalent bonds in methane?

Simple molecules and covalent bonds

Which equation shows the neutralisation of nitric acid by sodium hydroxide?

The characteristic properties of acids and bases

What is the relative formula mass for ammonium nitrate, $\text{NH}_4\text{NO}_3$?

Relative masses of atoms and molecules

When concentrated aqueous sodium chloride is electrolysed with inert electrodes, gases X and Y are produced at the electrodes shown. What are X and Y?

Electrolysis

Four changes of state for ethanol are shown below. 1 condensation 2 evaporation 3 freezing 4 boiling In which of these changes do the particles become further apart?

Solids, liquids and gases

Four statements about hydrogen fuel cells are given. 1 The fuel cell changes chemical energy into electrical energy. 2 Within the fuel cell, hydrogen reacts with oxygen. 3 Carbon dioxide and water are formed in the fuel cell. 4 The hydrogen fuel is taken from the air. Which statements are correct?

Hydrogen–oxygen fuel cells

5 g of four different fuels are ignited and positioned beneath a beaker holding $50\text{ cm}^3$ of water. The water temperature is measured at the beginning and again after five minutes. Which fuel gives out the most energy?

Fuels

Which of these changes make the rate of reaction faster? 1 raising the concentration of the reactants 2 making the particle size of a solid reactant larger 3 raising the temperature

Rate of reaction

Which reaction can be reversed?

Reversible reactions and equilibrium

The chemical equation for the reaction of iron(III) oxide with carbon is given below. $2\text{Fe}_2\text{O}_3 + 3\text{C} \rightarrow 4\text{Fe} + 3\text{CO}_2$ What type of reaction does iron(III) oxide undergo?

Redox

When copper(II) carbonate reacts with dilute hydrochloric acid, copper(II) chloride is produced. What are the other substances produced in this reaction?

Preparation of salts

Rubidium belongs to Group I, whereas strontium belongs to Group II in the Periodic Table. Which row gives the nature of rubidium oxide, $\text{Rb}_2\text{O}$, and strontium oxide, $\text{SrO}$?

Oxides

Magnesium sulfate is a soluble solid that forms when insoluble magnesium oxide reacts with dilute sulfuric acid. Which method is used to obtain solid magnesium sulfate?

Preparation of salts

Q and R are elements in the same period of the Periodic Table. Q contains 7 electrons in its outer shell, and R contains 2 electrons in its outer shell. Which statement about Q and R is correct?

Arrangement of elements

Which of these statements about alkali metals is correct?

Group I properties

Which statement shows that water is a compound?

Elements, compounds and mixtures

An aqueous solution of bromine is added to aqueous sodium iodide. $\text{bromine} + \text{sodium iodide} \rightarrow \ldots 1 \ldots + \ldots 2 \ldots$ Which products are formed in this reaction?

Group VII properties

Which row gives the characteristics of a transition element?

Transition elements

Which row gives the properties of argon?

Noble gases

Which row correctly identifies the properties of zinc?

Properties of metals

The applications of metals are determined by their properties. Which property is required for the use shown?

Uses of metals

Which compounds both cause acid rain?

Air quality and climate

P, Q, R and S are metals. P reacts with dilute hydrochloric acid and produces hydrogen. Q reacts very vigorously with water. R reacts with water, giving hydrogen. S is obtained by heating its oxide with carbon. Which row identifies the metals?

Reactivity series

When iron rusts, which compound is produced?

Corrosion of metals

Which reaction inside the blast furnace gives out heat energy?

Extraction of metals

A wax candle is produced from a blend of hydrocarbons. The candle is then ignited and put inside a gas jar together with a strip of cobalt(II) chloride test paper, as shown. Soon afterwards, the oxygen in the jar is exhausted and the candle flame extinguishes. Which substance is detected by the cobalt(II) chloride paper?

Identification of ions and gases

An atom of element X contains: • 5 protons • 6 neutrons • 5 electrons. Which of the following statements about element X are correct?

Atomic structure and the Periodic Table

Urea, $\text{CO(NH}_2\text{)}_2$, is used as a fertiliser. Which element that plants require for improved growth is supplied by urea?

Fertilisers

The percentage composition of the gases in Neptune’s atmosphere is shown. Which statement about the atmospheres of Neptune and Earth is correct?

Elements, compounds and mixtures

Which row gives the general formula for alkenes and for alcohols?

Formulae, functional groups and terminology

A molecule is represented by the formula $\text{C}_2\text{H}_5\text{Cl}$. State its chemical name?

Naming organic compounds

Which compound causes aqueous bromine to lose its colour quickly?

Alkenes

Compound Z possesses the molecular formula $\text{C}_2\text{H}_6\text{O}$. Which statement about compound Z is correct?

Formulae, functional groups and terminology

What is the formula of the salt produced when calcium carbonate reacts with aqueous ethanoic acid?

Preparation of salts

Rock salt contains salt and sand mixed together. The separation procedure for removing the sand from the salt is shown below. step 1 Break up the rock salt, add warm water, and stir. step 2 Pass the mixture through filter paper in a funnel. step 3 Remove the water by evaporation to form salt crystals. Which statement about this procedure is correct?

Separation and purification

Chromatography is used to separate mixture Y, together with dyes E, F, G and H. The chromatogram is shown. Which dyes are contained in mixture Y?

Chromatography

A fractionating column separates the hydrocarbon fractions in petroleum using fractional distillation. Which row gives the properties of the fractions that condense at the top of the fractionating column?

Separation and purification

Which row gives the properties of lithium fluoride?

Ions and ionic bonds

If acid is added to salt X, a gas is given off that makes limewater turn milky. If sodium hydroxide is added to salt X, a gas is given off that turns litmus paper blue. What is X?

Identification of ions and gases

Ammonia, $\text{NH}_3$, forms a covalent molecule. Which diagram illustrates the outer-shell electron arrangement in a molecule of ammonia?

Simple molecules and covalent bonds

Which substance is said to have a giant covalent structure?

Giant covalent structures

When sodium burns in oxygen, sodium oxide is formed. What balanced equation represents this reaction?

Formulae

State the relative formula mass of $\text{Mg(OH)}_2$.

Relative masses of atoms and molecules

Dilute sulfuric acid is electrolysed with inert electrodes. The apparatus is arranged as shown. $30\ \text{cm}^3$ of a gas is collected at the cathode, while a different gas is collected at the anode. Which row is correct?

Electrolysis

Nitrogen is warmed inside a balloon, causing the balloon to expand a little. Which of the following statements about the nitrogen molecules are correct? 1. They get farther apart. 2. They move faster. 3. They stay the same distance apart. 4. Their speed does not change.

Solids, liquids and gases

The flow diagram illustrates a hydrogen-oxygen fuel cell. Which row indicates the inputs and outputs?

Hydrogen–oxygen fuel cells

Which statement refers to an exothermic reaction?

Exothermic and endothermic reactions

Which row shows the changes that all make the rate of a chemical reaction increase?

Rate of reaction

When a student heats hydrated copper(II) sulfate, the blue crystals turn into a white powder. What should the student do to change it back?

Physical and chemical changes

Acidified aqueous potassium manganate(VII) forms a purple solution. What does the (VII) in potassium manganate(VII) indicate?

Redox

An excess of hydrochloric acid is introduced into aqueous sodium hydroxide that contains thymolphthalein. Which colour change is seen?

The characteristic properties of acids and bases

Details about four oxides, J, K, L and M, are given. J gives off ammonia when it is added to aqueous ammonium chloride. K reacts with aqueous sodium hydroxide. L is the oxide of an element in Group I. M is an oxide of an element from the top-right part of the Periodic Table. Which row is the correct one?

Oxides

Three ways of making salts are shown here. 1 acid + metal 2 acid + metal carbonate 3 acid + metal oxide Which of these methods can be used to prepare copper(II) chloride?

Preparation of salts

Which group of elements illustrates the transition from metallic to non-metallic character across one period of the Periodic Table?

Arrangement of elements

The diagram illustrates the reaction that takes place when potassium is added to water. $\text{2K} + \text{2H}_2\text{O} \rightarrow \text{2KOH} + \text{H}_2$ Which row is the correct one?

Group I properties

The diagrams show some elements, compounds and mixtures. Which row identifies the numbered substances?

Elements, compounds and mixtures

Which of the following statements about bromine is correct?

Group VII properties

What is a common characteristic of transition elements?

Transition elements

Which statement about the elements in Group VIII of the Periodic Table is correct?

Noble gases

The flow chart illustrates some properties of four solid elements. Which of the elements are non-metals?

Properties of metals

Which statement concerning copper or aluminium is correct?

Properties of metals

Water drawn from a reservoir is sent to the water works, where purification stage 1 occurs and is then followed by stage 2. What are stage 1 and stage 2?

Water

Calcium combines with cold water to give hydrogen. When lead is heated in air, it reacts only slowly to make an oxide, but it shows almost no reaction with steam. Silver shows no reaction with air or water. Zinc, on heating with steam, produces hydrogen. What is the reactivity order, beginning with the least reactive?

Reactivity series

Which of the following statements about rusting is correct?

Corrosion of metals

Which of the following statements about extracting iron in a blast furnace are correct?

Extraction of metals

Which of the following statements about water are correct?

Water

Atoms X and Y have the same mass number, but their atomic numbers are different. Which of the following statements about X and Y is correct?

Atomic structure and the Periodic Table

What substance do farmers use to improve plant growth?

Fertilisers

The three air pollutants, X, Y and Z, are outlined below. X is a poisonous gas produced when an alkane undergoes incomplete combustion. Y is produced when vegetation decomposes and it adds to global warming. Z leads to breathing difficulties and acid rain. What are the identities of X, Y and Z?

Air quality and climate

The displayed formula of an organic compound is given. Which homologous series does this compound belong to?

Formulae, functional groups and terminology

Kerosene is one of the fractions obtained from petroleum. What is kerosene used for in practice?

Fuels

Hydrocarbon P undergoes cracking to produce compound Q and hydrogen. Compound R is made by the addition polymerisation of compound Q. Which homologous series do P, Q and R each belong to?

Alkenes

Which process includes combustion? (Some of the reaction products are not labelled in the diagram.)

Exothermic and endothermic reactions

What products are formed when ethanoic acid reacts with aqueous sodium hydroxide?

Preparation of salts

Which of the following statements are true?

Elements, compounds and mixtures

A conical flask containing sodium hydroxide solution and a few drops of methyl orange indicator is titrated with dilute hydrochloric acid. Which apparatus is used to deliver the hydrochloric acid?

Acid–base titrations

What might the melting point and boiling point be for water that has an impurity dissolved in it?

Solids, liquids and gases

The symbols for two different isotopes of element $\text{S}$ are given as $^m_n\text{S}$ and $^p_q\text{S}$. The letters m, n, p and q stand for whole numbers. Which of the following statements about m, n, p and q are correct? 1. $m = p$ 2. $n = q$ 3. $m > q$

Isotopes

Element X reacts with air to produce an acidic gas that turns potassium manganate(VII) colourless. Identify X.

Oxides

Which statement concerning potassium fluoride is correct?

Ions and ionic bonds

In which molecule are all outer-shell electrons used for covalent bonding?

Simple molecules and covalent bonds

What is the chemical formula for potassium oxide?

Ions and ionic bonds

Magnesium nitrate is shown by the formula $\text{Mg(NO}_3)_2$. Calculate the relative formula mass of magnesium nitrate.

Relative masses of atoms and molecules

Dilute sulfuric acid is electrolysed with inert electrodes. What is formed at the anode?

Electrolysis