Oct/Nov 2024

Which row gives both a property of a gas and the correct reason for that property?

Solids, liquids and gases

Compound X is made up of carbon, hydrogen and oxygen only. Its $M_r$ is $90$. In $100\,\text{g}$ of compound X, there are $40.0\,\text{g}$ of carbon and $6.7\,\text{g}$ of hydrogen. How many oxygen atoms are present in one molecule of compound X?

Formulae

Aqueous copper(II) sulfate is electrolysed with copper electrodes. Which row gives the changes that occur during the electrolysis?

Electrolysis

Which row gives one benefit and one drawback of using a hydrogen-oxygen fuel cell to power a road vehicle?

Hydrogen–oxygen fuel cells

Which of the following statements about exothermic and endothermic reactions is correct?

Exothermic and endothermic reactions

Two gases combine to form one product. Raising the pressure changes the rate of this reaction. Platinum is used as a catalyst. Which row states one effect of increasing the pressure on this reaction and one effect of adding platinum to this reaction?

Rate of reaction

Calcium carbonate reacts with an excess of dilute hydrochloric acid and produces carbon dioxide. This reaction is studied in two experiments. The reaction rates are compared by recording the volume of carbon dioxide produced over time in each experiment. Graphs are then drawn to compare the two rates. Which statement about experiments 1 and 2 is correct?

Rate of reaction

When calcium carbonate is heated in a sealed container, it breaks down to give calcium oxide and carbon dioxide. Calcium oxide and carbon dioxide can then join together again to produce calcium carbonate. After a while, a point is reached at which calcium carbonate is decomposing, and calcium oxide and carbon dioxide are recombining at the same rate. What is this point called?

Reversible reactions and equilibrium

Which combination of conditions is employed in the Contact process?

Preparation of salts

Copper produces a red oxide, $\text{Cu}_2\text{O}$, and a black oxide, $\text{CuO}$. When a catalyst is present, aqueous hydrogen peroxide, $\text{H}_2\text{O}_2$, decomposes to make water. The black oxide contains copper in a .....1..... oxidation state than the red oxide does. When water is formed, hydrogen peroxide is .....2...... . Which words correctly fill gaps 1 and 2?

Redox

An organic compound, X, has a molecular formula $\text{C}_4\text{H}_8\text{O}_2$ and changes damp blue litmus paper to red. What is the displayed formula of X?

Carboxylic acids

If temperature and pressure are kept the same, which gas diffuses at the same rate as nitrogen?

Diffusion

Which statement concerning oxides is correct?

Oxides

A student is given suitable apparatus, distilled water and the reagents listed below. solid magnesium hydroxide; solid lead carbonate; dilute nitric acid; aqueous sodium chloride; aqueous sodium sulfate. Which salts is the student able to make as a pure dry sample?

Preparation of salts

On heating, crystals of copper(II) sulfate, $\text{CuSO}_4\cdot5\text{H}_2\text{O}$, undergo the reaction shown below. $\text{CuSO}_4\cdot5\text{H}_2\text{O}(s) \rightarrow \text{CuSO}_4(s) + 5\text{H}_2\text{O}(g)$ If .....1..... copper(II) sulfate, which has a .....2..... colour, is heated, it produces .....3..... copper(II) sulfate, which has a .....4..... colour. Which words should be used to fill gaps 1, 2, 3 and 4?

Physical and chemical changes

Which formula shows the oxide formed by element Z in Group II of the Periodic Table?

Arrangement of elements

Element X belongs to Group I. A few facts about element X are listed below. • X is not the Group I element with the lowest density. • X is more reactive than potassium. • X has an $A_r$ value below $100$. Which element is X?

Group I properties

A student gives three statements about metals and non-metals. 1. Every alloy includes at least one metal. 2. All metals conduct heat and electricity well. 3. Every solid non-metal is malleable. Which of these statements are correct?

Properties of metals

Group I elements and transition elements are metals. Student X says that the Group I elements are higher than hydrogen in the reactivity series, but that not every transition element is higher than hydrogen. Student Y says that the densities of Group I elements are lower than the densities of transition elements. Which students are correct?

Reactivity series

The equations for three reactions are shown below. 1 $2\text{O}^{2-} \rightarrow \text{O}_2 + 4\text{e}^-$ 2 $\text{C} + \text{O}_2 \rightarrow \text{CO}_2$ 3 $\text{CaO} + \text{SiO}_2 \rightarrow \text{CaSiO}_3$ These reactions occur during the extraction of metals. Which row is the correct one?

Extraction of metals

The water supplied to homes is treated so that it is safe to drink. Which row identifies the treatment and its effect?

Water

Sodium phosphate, $\text{Na}_3\text{PO}_4$, and ammonium nitrate, $\text{NH}_4\text{NO}_3$, are both employed as fertilisers. Which row gives the correct percentage by mass of the element in each compound that helps plant growth?

Relative masses of atoms and molecules

X and Y are both elements, and one of them is a non-metal. 1 mole of X is mixed with 1 mole of Y, then the mixture is heated. X and Y react fully to produce substance Z. Substance Z cannot be readily separated back into X and Y. Three statements are provided. Which statements are correct?

Elements, compounds and mixtures

Three processes are shown. 1 the breakdown of vegetation 2 exhaust emissions from a car engine 3 photosynthesis Which row shows a gas produced in each process?

Air quality and climate

Which compound is neither an alkane, alkene, alcohol nor carboxylic acid?

Formulae, functional groups and terminology

Alkenes may be obtained by cracking alkanes, for example decane, $\text{C}_{10}\text{H}_{22}$. Which equation represents the cracking of decane to form two different alkenes and at least one additional product?

Alkanes

Alkenes react with bromine in an addition reaction to make dibromoalkanes. Which statement is the correct one?

Alkenes

For the complete combustion of 2 moles of ethanol, how many moles of oxygen are needed?

The mole and the Avogadro constant

The two reactions below are given. For reaction 1 $\text{CH}_2\text{CH}=\text{CH}_2\text{OH} + \text{H}_2 \xrightarrow{\text{Ni}}$ compound X For reaction 2 compound X $\xrightarrow{\text{acidified } \text{KMnO}_4\text{(aq)}}$ compound Y Which row is the correct one?

Alcohols

A part of a protein’s structure is shown. How many amino acid monomer molecules were used to build this part of the structure?

Polymers

What apparatus is used to measure precisely $27.3\,\text{cm}^3$ of a liquid?

Experimental design

A student carries out a titration of aqueous sodium hydroxide using $0.1\,\text{mol dm}^{-3}$ hydrochloric acid. The results from the titration are then used to work out the concentration of the aqueous sodium hydroxide. Which row is correct?

Acid–base titrations

A mixture containing four coloured dyes is tested by chromatography. The outcome is shown. Which alteration would make it possible to view the four coloured dyes separately?

Chromatography

An ion has an electronic configuration of $2,8,8$. It carries a $2-$ charge and has a nucleon number of $36$. How many neutrons are in the nucleus of this ion?

Atomic structure and the Periodic Table

An aqueous solution contains cations of metal X. When a few drops of aqueous sodium hydroxide are added to the solution, a precipitate is formed. The precipitate then dissolves in excess aqueous sodium hydroxide. Which metal could X be?

Identification of ions and gases

The formulas of two ions are shown: $^{72}_{34}X^{2-}$ and $^{74}_{34}X^{2-}$. Which statement is correct?

Isotopes

Which two molecules contain an equal number of electrons in covalent bonds?

Simple molecules and covalent bonds

Chrome alum is a salt made up of two different cations together with one anion. The ions present in chrome alum are $\text{K}^+$, $\text{Cr}^{3+}$ and $\text{SO}_4^{2-}$. What is the formula of this salt?

Formulae

The table shows some details about barium and chlorine. On the basis of this information alone, a student makes three statements. Which of these statements are correct?

Ion and ionic bonds

What mass of carbon has an equal number of atoms to $16.0\,\text{g}$ of sulfur?

The mole and the Avogadro constant

Helium gas and argon gas are combined in a sealed container at room temperature and pressure (r.t.p.). What occurs when both gases are in the container?

Diffusion

Compound Z consists only of carbon, hydrogen and oxygen. By mass, Compound Z is $48.65\%$ carbon and $8.11\%$ hydrogen. Determine the empirical formula of Z.

Formulae

Which fertiliser has the greatest percentage by mass of nitrogen? $[M_r:\ \text{NH}_4\text{NO}_3, 80;\ (\text{NH}_4)_3\text{PO}_4, 149;\ (\text{NH}_4)_2\text{SO}_4, 132;\ (\text{NH}_2)_2\text{CO}, 60]$

Relative masses of atoms and molecules

A diagram of an electrolytic cell is shown. Which statement is correct?

Electrolysis

An aqueous solution containing copper(II) nitrate and silver nitrate is electrolysed using pure copper electrodes. Which ionic half-equation shows the process taking place at the anode?

Electrolysis

What is one drawback of using a hydrogen-oxygen fuel cell to power a car?

Hydrogen–oxygen fuel cells

When chemical reaction X occurs, thermal energy is released. Which row shows the correct information for this reaction?

Exothermic and endothermic reactions

Which statement concerning a physical change is correct?

Physical and chemical changes

Gas P breaks down to produce gas Q. $xP \rightarrow yQ$. Two experiments are carried out to investigate the rate of reaction. All conditions are identical apart from the use of two different temperatures, $T_1$ and $T_2$. The outcomes are shown on graphs, both drawn using the same scale. Which row is correct?

Rate of reaction

Samples of nitrogen and hydrogen are mixed and left until equilibrium is reached. The equation is given as: $\text{N}_2 + 3\text{H}_2 \rightleftharpoons 2\text{NH}_3 \qquad \Delta H = -92\,\text{kJ mol}^{-1}$. The temperature is raised and a new equilibrium is then established. Which statement about this new equilibrium is correct?

Reversible reactions and equilibrium

In the diagram, R shows one of the reactions in the Contact process. Which statement is correct?

Reversible reactions and equilibrium

Substance X is a simple molecular substance and substance Y has a giant covalent structure. Which row is correct?

Giant covalent structures

Peroxodisulfate ions, $\text{S}_2\text{O}_8^{2-}$, undergo reaction with iron(II) ions, $\text{Fe}^{2+}$. $\text{S}_2\text{O}_8^{2-} + 2\text{Fe}^{2+} \rightarrow 2\text{SO}_4^{2-} + 2\text{Fe}^{3+}$. In this reaction, sulfur and iron are the only elements that are oxidised or reduced. Which row is correct?

Redox

Which solid reacts with dilute hydrochloric acid to give off a gas?

The characteristic properties of acids and bases

Which aqueous solution of concentration $1\,\text{mol dm}^{-3}$ has the greatest pH?

The characteristic properties of acids and bases

Oxide Q is added to separate samples of dilute hydrochloric acid and aqueous potassium hydroxide. Each reaction forms a salt and water. Which statement is correct?

Oxides

The table lists four methods for preparing pure salts. Which row identifies a method for making a pure sample of each named salt?

Preparation of salts

Which property is used to decide the sequence of elements in the Periodic Table?

Arrangement of elements

Which statement gives the reason that helium and neon are unreactive?

Noble gases

Substance X is able to conduct electricity when it is solid. Substance X can be hammered into shape. Which statement is correct?

Properties of metals

Aluminium and copper both conduct electricity well. Why is aluminium chosen for overhead electrical cables rather than copper?

Uses of metals

Heating the oxide of Z with carbon causes it to be reduced. What is Z?

Reactivity series

The diagram illustrates an atom of element Z. Which symbol for element Z is correct?

Atomic structure and the Periodic Table

A metal ore includes the oxide, MO. Metal M produces coloured compounds. If a piece of iron is added to a solution that contains aqueous $\text{M}^{2+}$ ions, M is displaced. Which row is correct?

Reactivity series

Iron may be obtained from the ore hematite. What is the greatest mass of iron that can be obtained from 500 kg of hematite? $[A_r: \text{O}, 16; \text{Fe}, 56]$

Relative masses of atoms and molecules

Which row shows one benefit and one drawback of fertilisers?

Fertilisers

Which row about the harmful effects of air pollutants is accurate?

Air quality and climate

How many distinct unbranched esters have the molecular formula $\text{C}_4\text{H}_8\text{O}_2$?

Formulae, functional groups and terminology

Petroleum is separated in a fractionating column. Which of the following statements are correct?

Separation and purification

Which of these statements about hydrocarbons is correct?

Formulae, functional groups and terminology

Two statements are presented. Which of the following descriptions of these statements is correct?

Elements, compounds and mixtures

During a titration, a $25.0\,\text{cm}^3$ portion of $0.100\,\text{mol dm}^{-3}$ sodium hydroxide is neutralised exactly by $16.2\,\text{cm}^3$ of dilute sulfuric acid. The reaction equation is given below. $\text{H}_2\text{SO}_4 + 2\text{NaOH} \rightarrow \text{Na}_2\text{SO}_4 + 2\text{H}_2\text{O}$ Calculate the concentration of the dilute sulfuric acid.

Acid–base titrations

Three liquids, X, Y and Z, are examined, and the outcomes are given below. Tests: • add anhydrous cobalt(II) chloride: X changes from blue to pink, Y no change, Z changes from blue to pink • measure boiling point: X $100^\circ\text{C}$, Y $78^\circ\text{C}$, Z $103^\circ\text{C}$ What can be inferred about X, Y and Z from this evidence?

Water

A specimen of element Q has two isotopes. The diagram gives the relative abundances and relative masses for these isotopes. What is the relative atomic mass, $A_r$, of this Q sample?

Isotopes

Compound Q dissolves in water. If dilute sulfuric acid is added to a solution of Q, a white precipitate is formed. On heating Q with aqueous sodium hydroxide and aluminium foil, a gas is evolved that turns damp red litmus paper blue. What is Q?

Identification of ions and gases

Which of the following statements about electrical conductivity is correct?

Properties of metals

Which substance is neither malleable nor conducts electricity through the motion of electrons across a lattice of atoms?

Metallic bonding

What is ethene's relative molecular mass, $M_r$?

Relative masses of atoms and molecules

State the relative molecular mass, $M_r$, of $\text{N}_2\text{O}$.

Relative masses of atoms and molecules

Which one has the largest mass of oxygen?

Relative masses of atoms and molecules

Fig. 1.1 presents the electronic configurations of five atoms, D, E, F, G and H. Use these configurations to answer the questions. Any configuration may be chosen once, more than once or not at all. State which electronic configuration, D, E, F, G or H, represents:

Atomic structure and the Periodic Table

Iron is obtained in a blast furnace by reducing iron(III) oxide with carbon monoxide. $\text{Fe}_2\text{O}_3 + 3\text{CO} \rightarrow 2\text{Fe} + 3\text{CO}_2$

Extraction of metals

Fig. 3.1 illustrates the equipment used to carry out the electrolysis of concentrated aqueous sodium chloride with graphite electrodes.

Electrolysis

This item concerns alkanes and alkenes.

Alkenes

A student places large lumps of copper(II) carbonate into dilute hydrochloric acid, and the copper(II) carbonate is in excess.

Rate of reaction

Fig. 6.1 illustrates the structures of zinc sulfide and disulfur dichloride. Zinc sulfide has a structure like diamond.

Giant covalent structures

Propanoic acid may be written using the formula $\text{CH}_3\text{CH}_2\text{COOH}$.

Carboxylic acids

Fig. 1.1 presents the electronic configurations of five atoms, A, B, C, D and E. Any one of these configurations may be used once, more than once or not used at all.

Atomic structure and the Periodic Table

Iron is obtained in the blast furnace by reducing iron(III) oxide, $\text{Fe}_2\text{O}_3$. The overall process can be divided into three stages.

Extraction of metals

Fig. 3.1 shows the setup used to carry out the electrolysis of dilute sulfuric acid with graphite electrodes.

Electrolysis

The question focuses on alkanes and alkenes.

Alkenes

A student places large pieces of zinc into dilute hydrochloric acid, with the zinc present in excess.

Rate of reaction

Fig. 6.1 presents the structures of boron nitride and hydrazine.

Simple molecules and covalent bonds

Esters are described by the formula $\text{C}_n\text{H}_{2n}\text{O}_2$.

Polymers

A teacher carries out an investigation into the electrolysis of molten lead(II) bromide. At room temperature, lead(II) bromide is a solid. Fig. 1.1 shows the apparatus used by the teacher.

Electrolysis

A learner carries out titrations on four samples of $0.800\,\text{mol dm}^{-3}$ aqueous sodium hydroxide, $\text{NaOH(aq)}$, using aqueous ethanedioic acid. For titration 1, the learner: • rinses a burette and then fills it with aqueous ethanedioic acid • uses a volumetric pipette to transfer $25.0\,\text{cm}^3$ of $\text{NaOH(aq)}$ into a conical flask • adds thymolphthalein indicator to the conical flask • sets the conical flask on a white tile • runs aqueous ethanedioic acid from the burette while swirling the flask, then adds it drop by drop close to the end-point until the solution has just changed colour. The learner carries out the titration three further times.

Acid–base titrations

A student carries out an investigation on solid Y and solution Z.

Identification of ions and gases

Argentan is an alloy made up only of zinc, nickel and copper. Zinc and nickel both react with dilute hydrochloric acid, but copper does not react with dilute hydrochloric acid. Devise an investigation to determine the percentage by mass of copper in a powdered sample of argentan. Your plan must make use of common laboratory apparatus, argentan and dilute hydrochloric acid. No other chemicals may be used.

Experimental design

A student carries out an experiment to prepare pure hydrated copper(II) sulfate crystals, $\text{CuSO}_4\cdot5\text{H}_2\text{O}$.

Preparation of salts

A student carries out titrations on four separate aqueous sodium carbonate samples using $0.500\,\text{mol dm}^{-3}$ dilute hydrochloric acid, $\text{HCl(aq)}$.

Acid–base titrations

A student examines solution P and solution Q.

Identification of ions and gases

Muntz metal is an alloy containing zinc and copper. Zinc reacts with dilute sulfuric acid, whereas copper does not react with dilute sulfuric acid.

Experimental design