Feb/March 2024

Which of the following statements about a solid, a liquid or a gas is correct?

Solids, liquids and gases

The equations for two reactions are displayed below. equation 1: $\text{C} + \text{CO}_2 \rightarrow x\,\text{CO}$ equation 2: $2\text{C}_2\text{H}_6 + 7\text{O}_2 \rightarrow 4\text{CO}_2 + y\,\text{H}_2\text{O}$ Which row gives the value of $x$, the value of $y$ and the equations that are redox reactions?

Redox

Concentrated aqueous sodium chloride is electrolysed with graphite electrodes. Which substance is produced at the cathode?

Electrolysis

Which row shows the changes that happen when metals burn in oxygen?

Oxides

When calcium carbonate is heated strongly, carbon dioxide gas is given off. Which words describe the kind of change that takes place?

Physical and chemical changes

Which row correctly describes a hydrogen-oxygen fuel cell?

Hydrogen–oxygen fuel cells

Which of the following lists includes only chemical changes?

Physical and chemical changes

In two separate experiments, an excess of calcium carbonate is added to $50\,\text{cm}^3$ of dilute hydrochloric acid at different concentrations. The volume of gas formed in experiment 1 and experiment 2 is recorded at 30-second intervals. The results are given in the table. Which diagram shows the data collected?

Rate of reaction

An experiment is arranged as shown. The mass of the conical flask and its contents is recorded every 30 seconds. Which statement about the reaction and the changes made to the reaction conditions is correct?

Rate of reaction

Which reaction can be reversed?

Reversible reactions and equilibrium

Silver oxide reacts with magnesium to produce silver and magnesium oxide. $\text{Ag}_2\text{O} + \text{Mg} \rightarrow 2\text{Ag} + \text{MgO}$. Which substance is oxidised in this reaction?

Redox

Which diagram shows a mixture of compounds?

Elements, compounds and mixtures

Compound X is soluble in water, producing an aqueous solution. Methyl orange is then introduced into the aqueous compound X. The methyl orange becomes red. What is compound X?

The characteristic properties of acids and bases

Dilute hydrochloric acid reacts with aqueous sodium hydroxide during a neutralisation reaction. Which two ions take part in this neutralisation reaction?

The characteristic properties of acids and bases

The table lists some properties of several elements in Group I of the Periodic Table. Rubidium is another element in Group I of the Periodic Table. Which row gives the properties of rubidium?

Group I properties

Copper(II) sulfate crystals are blue. They are produced by adding an excess of copper(II) oxide to sulfuric acid. The mixture is heated while being stirred. It is then filtered, and the filtrate is left to evaporate, which forms blue crystals. Why is filtration required?

Preparation of salts

Which barium salts dissolve in water?

Ions and ionic bonds

Which of the following statements about the properties of elements in Group I or Group VII is correct?

Group I properties

Rubidium and strontium are both located in Period 5 of the Periodic Table. Rubidium is in Group I. Strontium is in Group II. Which of the following statements about these elements is correct?

Arrangement of elements

A company requires a metal that has a low density, resists corrosion, and is a good electrical conductor. Which metal ought it to choose?

Uses of metals

Which of the following statements about stainless steel is correct?

Alloys and their properties

Which statements account for why a water tap made of steel is electroplated with copper?

Electrolysis

There are four ions shown below. $\text{N}^{3-} \quad \text{Al}^{3+} \quad \text{Li}^+ \quad \text{Cl}^-$ Which two ions have the same electronic configuration?

Ions and ionic bonds

The table gives the outcomes of heating four metals separately with oxides of different metals. The four metals are iron, copper, magnesium and Y. The results are displayed below. What is the order of reactivity of the metals, least reactive first?

Reactivity series

From its ore, which metal is obtained most readily?

Extraction of metals

Why is distilled water used for chemical experiments instead of tap water?

Separation and purification

Which class of compound also gives its name to a homologous series?

Formulae, functional groups and terminology

A diagram of the fractional distillation of petroleum is shown. Which fraction has the lowest volatility?

Solids, liquids and gases

Which formula shows an unsaturated hydrocarbon?

Alkenes

The structural formula of an organic compound is displayed. This compound is then tested separately using thymolphthalein and aqueous bromine. Which row shows the final colour seen in each test?

Formulae, functional groups and terminology

Which statement gives a description of methane?

Simple molecules and covalent bonds

Which row states why plastics such as poly(ethene) are a cause of pollution?

Polymers

Two experiments are given below. experiment 1: A large amount of copper(II) sulfate is stirred into a beaker containing water. After a few minutes, crystals that have not dissolved can be seen at the bottom of the beaker. experiment 2: Sea water is distilled. Distilled water and solid impure salt are collected separately in two containers. Which statement is correct?

Separation and purification

Which of the following statements about isotopes is correct?

Isotopes

When an aqueous sample of X is warmed with aqueous sodium hydroxide and small pieces of aluminium, a gas is evolved that turns damp red litmus paper blue. If aqueous sodium hydroxide is then added to a different aqueous sample of X, a pale green precipitate is seen. What is X?

Identification of ions and gases

Which statement concerning the ions produced by elements in Group VII of the Periodic Table is correct?

Group VII properties

Which row gives the properties of potassium bromide?

Ions and ionic bonds

Which statement gives the reason that graphite is used as a lubricant?

Giant covalent structures

What is the balanced equation for magnesium reacting with dilute sulfuric acid?

The characteristic properties of acids and bases

The relative atomic mass, $A_r$, of an element is the mean mass of the isotopes of that element when compared with another particle. What particle is used for this comparison?

Isotopes

Solid X is heated for 600 seconds. The graph illustrates the heating curve produced. What is the melting point of X?

Solids, liquids and gases

Magnetite is an iron ore made up only of the ions $\text{Fe}^{2+}$, $\text{Fe}^{3+}$ and $\text{O}^{2-}$. State the formula of magnetite.

Ions and ionic bonds

Concentrated aqueous sodium chloride and dilute sulfuric acid are each electrolysed with inert electrodes. Which row shows the product formed at the cathode in each electrolysis?

Electrolysis

Electrolysis is used to break electrolytes down. Which rows are correct for each electrolyte?

Electrolysis

Which of these statements about hydrogen-oxygen fuel cells is correct?

Hydrogen–oxygen fuel cells

Which statement gives the definition of the activation energy, $E_a$, for a reaction?

Rate of reaction

The balanced equation for the complete combustion of ethyne, $\text{H-C} \equiv \text{C-H}$, is given below. $2\text{H-C} \equiv \text{C-H} + 5\text{O}=\text{O} \rightarrow 4\text{O}=\text{C}=\text{O} + 2\text{H-O-H}$ A list of bond energies is provided. What is the enthalpy change for the reaction when $1\,\text{mol}$ of ethyne is completely burned?

Exothermic and endothermic reactions

In experiment 1, small pieces of limestone are placed into dilute ethanoic acid at $40\,^{\circ}\text{C}$. The volume of carbon dioxide given off is recorded at fixed time intervals. The results are plotted on a graph. Which changes produce the results shown in experiment 2?

Rate of reaction

Within the Haber process, nitrogen is combined with hydrogen to form ammonia. $\text{N}_2(\text{g}) + 3\text{H}_2(\text{g}) \rightleftharpoons 2\text{NH}_3(\text{g})$ This forward reaction gives out heat. Which conditions will give the highest yield of ammonia?

Reversible reactions and equilibrium

Nitric acid is produced by the Ostwald process. The conditions for this process are: 1 a catalyst containing a transition element 2 a pressure of $10\,\text{atm}$ 3 a temperature of $800\,^\circ\text{C}$ Which of these conditions are also used in the Contact process?

Preparation of salts

Hydrogen iodide is dissolved in water. $\text{HI} \rightarrow \text{H}^+ + \text{I}^-$ Which row shows the end colours observed when the solution is tested using damp red litmus paper and acidified aqueous potassium manganate(VII)?

The characteristic properties of acids and bases

Which of the following statements about diffusion are correct? 1. Aqueous ions are unable to diffuse in water. 2. Diffusion happens because particles move randomly. 3. During diffusion, particles spread out in every direction. 4. Diffusion can occur only in solids and liquids.

Diffusion

Which of the following statements about aqueous ethanoic acid are correct?

The characteristic properties of acids and bases

Which element produces an acidic oxide?

Oxides

Which statement gives the properties of hydrochloric acid?

The characteristic properties of acids and bases

Elements P and Q contain the same number of electron shells. An atom of Q has a larger number of electrons in its outermost electron shell than an atom of P. Which statements are correct?

Atomic structure and the Periodic Table

Which substance reacts with dilute sulfuric acid so that a salt is formed and can then be separated from the mixture by filtration?

Preparation of salts

Astatine is placed beneath iodine in Group VII of the Periodic Table. Which row gives the correct description of astatine’s properties?

Group VII properties

Which characteristic of copper accounts for its classification as a transition element?

Transition elements

Brass is an alloy made from copper and zinc. Which statements are correct?

Alloys and their properties

The equation for how metal M reacts with aqueous zinc sulfate is shown below. $\text{M(s)} + \text{ZnSO}_4\text{(aq)} \rightarrow \text{MSO}_4\text{(aq)} + \text{Zn(s)}$ Which statement gives the reason that metal M reacts with aqueous zinc sulfate?

Reactivity series

Within the blast furnace, the impurity silicon(IV) oxide is eliminated when slag is formed. Which equation shows the formation of the substance that reacts with silicon(IV) oxide to produce slag?

Extraction of metals

Which one of the following statements about an atom of fluorine, $^{19}_{9}\text{F}$, is correct?

Atomic structure and the Periodic Table

Aluminium is obtained from bauxite using electrolysis. Which of the statements is correct?

Extraction of metals

Iron rusts, whereas aluminium does not corrode easily. Which statement accounts for the fact that aluminium does not corrode easily?

Corrosion of metals

Which chemicals may be used as a fertiliser to supply the three elements required for better plant growth?

Fertilisers

When water is added to anhydrous cobalt(II) chloride, what colour change takes place?

Transition elements

In what way do carbon dioxide and methane lead to global warming?

Air quality and climate

There are four statements about photosynthesis below. Which of these statements are correct?

Exothermic and endothermic reactions

Which molecules are classed as structural isomers?

Formulae, functional groups and terminology

Which of the following statements about the reaction between ethene and steam are correct?

Alkenes

Methane and chlorine combine to make chloromethane. Which row gives the required reaction conditions and the reaction type?

Alkanes

The structures of two different polymers, X and Y, are shown. In which row are the monomers and the bonds joining the monomers in polymers X and Y given correctly?

Polymers

The calcium isotopes shown are $^{40}_{20}\text{Ca}$ and $^{44}_{20}\text{Ca}$. Which statement accounts for the fact that these calcium isotopes have the same chemical properties?

Isotopes

Substance Q is examined by paper chromatography. The chromatogram obtained is shown. Which statement is correct?

Chromatography

Which statement describes a property of potassium iodide?

Elements, compounds and mixtures

The boiling point of methanal, $\text{CH}_2\text{O}$, is $-19\,^{\circ}\text{C}$. When the temperature is $-20\,^{\circ}\text{C}$, liquid methanal does not conduct electricity. In methanal, each carbon, hydrogen and oxygen atom has a noble gas electronic configuration. This configuration has been obtained by each atom in one of three ways: • gaining electrons • losing electrons • using shared electrons. Which statement explains the bonding between the carbon atom and the oxygen atom in methanal?

Simple molecules and covalent bonds

The arrangements of diamond and graphite are shown. Which statement about diamond and graphite is correct?

Giant covalent structures

Which row gives a description of metallic bonding, together with a property explained by reference to metallic bonding?

Metallic bonding

What is the relative molecular mass, $M_r$, for sulfur dioxide?

Relative masses of atoms and molecules

The substances below are listed. brass calcium oxide carbon monoxide diamond glucose hydrogen litmus magnesium bromide methyl orange sodium chloride stainless steel thymolphthalein water zinc oxide Use these substances to answer the questions that follow. Each substance may be chosen once, more than once, or not used at all.

Elements, compounds and mixtures

Table 2.1 lists the masses of several ions present in a $1000\,\text{cm}^3$ sample of river water.

Water

The elements are ordered in the Periodic Table into groups and periods.

Arrangement of elements

Alkenes form a homologous series of hydrocarbons produced when larger alkane molecules are cracked.

Alkenes

Samarium is classified as a metal.

Reactivity series

Sulfur is placed in Group VI of the Periodic Table as an element.

Relative masses of atoms and molecules

Magnesium belongs to Group II of the Periodic Table.

Atomic structure and the Periodic Table

Iron ore contains iron(III) oxide, Fe2O3. Iron is obtained from Fe2O3 in a blast furnace. Some of the reactions taking place in the blast furnace are shown below. equation 1 C + O2 -> CO2 equation 2 CaCO3 -> CaO + CO2 equation 3 CaO + SiO2 -> CaSiO3

Extraction of metals

The elements in Group VII of the Periodic Table are called the halogens, and they form halide ions.

Group VII properties

The topic of this question is acids, bases and alkalis. Table 3.1 lists the pH values for several substances.

The characteristic properties of acids and bases

The reaction between methanoic acid and ethanol, in the presence of a catalyst, is shown by the equation below. HCOOH + CH3CH2OH ⇌ X + H2O ΔH = -29.5 kJ/mol X is the ester that is produced.

Reversible reactions and equilibrium

At room temperature and pressure, both butane and but-1-ene are colourless gases.

Alkenes