M1Module 1 — Development of practical skills in chemistry
Note: most practical-skill testing is embedded within questions across the other topics, not listed here separately. Wherever you see a PS badge next to a question, that question also tests a practical skill (e.g. calculating a mean titre, evaluating an uncertainty, justifying a method) alongside its main content. This section only lists questions that test a practical skill on its own, without needing topic-specific content knowledge to answer. Because practical skills draw on knowledge from across the course, you may find it useful to revisit this section towards the end of your revision.
M1 Practical skills, apparatus & uncertainty
20(d)(i) — Complete a results table and calculate the mean titre from titration data
20(d)(ii) — Calculate the percentage uncertainty in a titration volume
18(c)(i) — Explain why a more dilute titrant concentration was used instead of the standard concentration for this titration
1 — Identify the procedure that would cause a smaller titre in a titration
18(e)(i) — Explain whether the percentage by mass of copper would be higher, lower, or the same if potassium iodide was not in excess
18(e)(ii) — Explain whether the percentage by mass of copper would be higher, lower, or the same if burette readings were taken from the top of the meniscus
18(f) — Suggest further modifications to improve the accuracy of the percentage by mass of copper
19(a)(i) — Complete a results table and calculate the mean titre from titration data
21(a)(ii) — Complete a results table and calculate the mean titre from titration data
M2Module 2 — Foundations in chemistry
Atoms, ions, and compounds
2.1 Atomic structure and isotopes
1 — Identify which sample is not an isotope of iodine from neutron and mass numbers
1 — Calculate the percentage abundance of an isotope from the relative atomic mass of a sample
16(b) — Determine the relative isotopic mass of an isotope from abundance and average atomic mass data
16(a) — Explain the meaning of the term weighted mean mass in the context of relative atomic mass
14 — Identify possible particles matching a given number of electrons and neutrons
16(a) — Complete a table of subatomic particles for atoms and ions of different isotopes
16(b)(i) — Calculate the relative atomic mass of an element from isotopic abundance data
1 — Identify the correct atomic structure (protons, neutrons, electrons) for a given ion
2.2 Relative mass
6 — Predict the formula of an ionic compound formed between elements from two given groups
16(c) — Deduce the possible identities of ions in an ionic compound from given electron configurations
1 — Identify which ion has a different number of electrons from the others
2.3 Formulae and equations (no questions in these papers)
Amount of substance
3.1 Amount of substance and the mole
6 — Calculate the number of electrons removed to form positive ions from a given mass of gas atoms
3 — Calculate the number of hydrogen atoms in a given amount of a compound
3 — Identify a possible molecular formula for a gas from its molecular mass
2 — Identify which statement gives the numerical value of the Avogadro constant
16(b)(ii) — Calculate the total number of ions in a given mass of an ionic compound
4 — Identify which sample contains the greatest number of molecules
5 — Identify a possible molecular formula for a substance from the mass of several molecules
1 — Identify which sample contains the greatest number of molecules
3 — Calculate the number of hydrogen atoms in a given mass of a hydrated compound
3 — Calculate the number of gas molecules present at a given mass concentration
3.2 Determination of formulae
4 — Identify which calcium compound has the greatest percentage by mass of calcium
8 — Identify a Group 2 metal from the mass of chloride formed in a reaction
18(c)(iii) — Compare two compounds to determine which provides more of a target element per tablet
3 — Identify an element from the mass ratio in which it forms an oxide
3 — Identify an element from the mass of oxide it forms
21(c)(i) — Calculate the mass of a raw material needed to produce a target mass of fertiliser
2 — Determine the formula of a metal oxide from mass data in a reduction reaction
2 — Identify an element from the mass of oxide it forms
16(d) — Calculate the empirical formula of a salt from percentage composition and deduce its ions
2 — Calculate the percentage by mass of an element in a hydrated compound
21(c)(iii) — Identify a complex ion and product formed in a described sequence of transition metal reactions
3.3 Moles and volumes
19(a) — Determine the volume of gas produced and suggest suitable apparatus for measuring it
20(c) — Determine the molecular formula of a volatile compound from its gas volume and mass
10 — Calculate the energy released in a reaction using enthalpy and molar gas volume data Also listed under Module 3 — Enthalpy
21(c) — Determine the molecular formula of a compound from its gas volume and mass 🖨️ (?)
2 — Identify the most likely equation for a reaction from given gas volumes
19(b) — Calculate the molar mass of a gas and suggest its molecular formula
15 — Identify correct statements about mole ratios in a given reaction
18(b)(ii) — Calculate the mass of product obtainable from a gas supply given a percentage yield
21(b) — Determine the oxidation state of a metal from given reaction data comparing two possible equations
16(d) — Calculate the mass of a reactant required to produce a target volume of product at a given yield
3.4 Reacting quantities
5 — Calculate the volume of acid required to react completely with a given amount of calcium oxide
7 — Calculate the mass of product formed from a reaction given a percentage yield
4 — Calculate the concentration of an acid from titration data
4 — Calculate the minimum mass of a base required to neutralise a spilled acid
20(b)(i) — Show by calculation the volume of base required to reach the end point of a titration
4 — Calculate the mass of base required to completely neutralise a tribasic acid
18(a) — Write an equation for a redox reaction and identify the elements oxidised and reduced Also listed under Module 2 — Acids and redox
5 — Calculate the minimum mass of a metal required to reduce a given mass of a metal oxide
6 — Calculate the volume of water required to dilute a solution to a target ion concentration
18(a) — Suggest the formula of a compound and write a full equation for its reaction with an acid
22(b)(i) — Show by calculation that one reagent is in excess in a neutralisation reaction
4 — Calculate the concentration of hydrogen peroxide in a disinfectant from titration data
19(a)(ii) — Calculate the mass of an active ingredient in a tablet using titration results
21(c)(ii) — Construct an equation, with state symbols, for a mineral reacting with an acid
4 — Calculate the concentration of species remaining after mixing an acid and a base
20(c)(i) — Construct the equation for a metal carbonate reacting with an acid
20(c)(ii) — Explain why two reactions of a carbonate with different acids produce different gas volumes
20(d)(i) — Construct an ionic equation for a metal reacting with an acid
3 — Identify the most sustainable process for producing a metal in terms of atom economy
21(a) — Write balanced equations for two reactions and identify the reaction type of a third Also listed under Module 3 — Reactivity trends
21(b) — Determine the mass of a compound in a tablet using an iodine-based titration method Also listed under Module 5 — Redox and electrode potentials
18(c)(ii) — Suggest why the chemist is more concerned with increasing the proportion of H2 that reacts than the proportion of N2 that reacts
3 — Calculate the hydrogen ion concentration in a mixture of two strong acids
18(a)(ii) — Write an equation for a described reaction
18(b)(i) — Construct the overall equation from a two-step reaction sequence
16(e)(i) — Write an equation for the preparation of a compound from two given reactants
19(a) — Write an equation, with state symbols, and state observations for a metal reacting with excess acid
Acids and redox
4.1 Acids, bases, and neutralisation (no questions in these papers)
4.2 Acid–base titrations (no questions in these papers)
4.3 Redox
3 — Determine the oxidation number of manganese in a compound
17(c)(i) — Define disproportionation and identify it using oxidation numbers
17(c)(ii) — State the systematic name for a given compound
2 — Determine the oxidation numbers of two elements in a given ionic compound
5 — Determine the oxidation number of nitrogen in a hydrated compound
6 — Identify which given reaction is a redox reaction
18(a) — Write an equation for a redox reaction and identify the elements oxidised and reduced Also listed under Module 2 — Amount of substance
22(b)(ii) — Determine the oxidation number of a transition metal in a compound
2 — Determine the formula of a compound formed from a given polyatomic ion charge
19(b)(i) — Explain, in terms of oxidation numbers, why disproportionation has taken place
21(a)(ii) — Write oxidation and reduction half-equations for a metal reacting with an acid
6 — Identify the equation representing a disproportionation reaction
14 — Identify correct statements about the redox behaviour of chlorine's electron configuration
16(b)(iii) — Suggest the oxidation states of an element in a compound containing two different states
4 — Identify which element is oxidised in a given redox equation
11 — Identify the redox reaction with the largest change in oxidation state for a given element
Electrons and bonding
5.1 Electron structure
15 — Identify correct electron configurations for given atoms and ions
1 — Identify the correct electron arrangement diagram for an atom of carbon
16(b)(iii) — Identify which ionisation numbers correspond to removing an electron from a full orbital
1 — Identify the correct arrangement of electrons in the p-orbitals of an atom
22(a) — Draw orbital shapes and complete electron configurations for a transition metal atom and its ion
16(a) — Complete an electron-in-boxes diagram for the orbital filling of an atom
16(b)(ii) — Write the full electron configuration of an atom 🖨️ (?)
16(a) — Show the electron configuration of an atom using electron-in-box diagrams
5.2 Ionic bonding and structure
16(b)(i) — Draw a dot-and-cross diagram for an ionic compound
17(a) — Draw a dot-and-cross diagram for the bonding in an ionic compound
5.3 Covalent bonding
16(a) — Draw a dot-and-cross diagram to show the bonding in a complex ion 🖨️ (?)
19(c) — Draw a dot-and-cross diagram for a polyatomic ion
Shapes of molecules and intermolecular forces
6.1 Shapes of molecules and ions
16(b) — Predict the shape and bond angle for two given ions
14 — Identify correct statements about the polarity, lone pairs, and shape of a given molecule
18(b)(i) — Explain the bond angle in a given molecule
16(e)(ii) — Draw a 3D diagram and predict a bond angle in a molecule using electron pair repulsion theory
6.2 Electronegativity and polarity
1 — Identify the correct definition of electronegativity
5 — Identify which compound has polar molecules
18(b)(ii) — Explain why two related molecules both have polar bonds but only one is a polar molecule
14 — Identify which reactions form a product with non-polar molecules
6.3 Intermolecular forces
16(c)(ii) — Explain the difference in boiling points between two hydrides down a group
14 — Identify which substances experience London forces
6 — Identify the bonds or interactions responsible for a difference in boiling points between two hydrogen halides
6.4 Hydrogen bonding
16(c)(i) — Explain the difference in boiling points between two hydrides
2 — Identify the correct explanation for water's anomalous melting point, boiling point, and density
M3Module 3 — Periodic table and energy
Periodicity
7.1 The periodic table
16(a) — Explain which block in the Periodic Table two given elements belong to
4 — Identify the element with atoms of the largest radius
7.2 Ionisation energies
5 — Identify the correct explanation for a first ionisation energy anomaly across a period
16(e)(i) — Explain a trend in first ionisation energy down a group
14 — Identify correct statements about properties of Group 2 elements Also listed under Module 3 — Reactivity trends
7 — Identify the correct order of first ionisation energies for a set of elements
16(b)(i) — Write an equation, with state symbols, for a given ionisation energy
16(b)(ii) — Explain how successive ionisation energies provide evidence for an element's group
18(a) — Complete a graph of first ionisation energy across a period
18(b) — Estimate the energy required to remove an electron from a gaseous atom
18(c) — Explain why the first ionisation energies of two elements are both higher than a third
18(d) — Explain why the first ionisation energy of beryllium is higher than that of boron
6 — Identify the element with the largest third ionisation energy
16(b) — Explain a trend in first and second ionisation energies down Group 2
16(b)(i) — Write an equation, with state symbols, for a given successive ionisation energy
16(b)(ii) — Explain why successive ionisation energies increase with ionisation number
16(b)(iii) — Explain how successive ionisation energy data provides evidence for electron shells
16(b)(iv) — Explain a trend or anomaly in first ionisation energy across a period
16(c)(i) — Add missing data points to a graph of first ionisation energy across a period
7 — Identify an element from a set of successive ionisation energies
7.3 Periodic trends in bonding and structure
7 — Identify a set of elements matching three given lattice structure types
16(c)* — Extended response: explain the physical properties of a metal, non-metal, and their compound using structure and bonding 🖨️ (?)
16(a) — Describe metallic bonding with a labelled diagram and explain electrical conductivity
13 — Identify which substances have London forces in the solid state
20(c)* — Extended response: explain the melting points of a set of elements in terms of bonding and structure
Reactivity trends
8.1 Group 2
17(a) — Write an equation for the preparation of a salt by neutralisation
17(b) — Explain the trend in reactivity of Group 2 elements down the group
9 — Identify the incorrect statement about the properties of Group 2 hydroxides
16(c)(i) — Write the equation for the reaction of a Group 2 oxide with water
16(c)(ii) — Suggest the approximate pH of solutions formed from two Group 2 oxides
14 — Identify correct statements about properties of Group 2 elements Also listed under Module 3 — Periodicity
21(a)(i) — State evidence that one metal is more reactive than another
4 — Identify which type of magnesium compound can be used as an antacid
21(a) — Write balanced equations for two reactions and identify the reaction type of a third Also listed under Module 2 — Amount of substance
12 — Identify the incorrect property of a Group 2 element
16(c)(ii) — Explain a trend in first ionisation energy and its effect on group reactivity
2 — Identify the correct statement about the reaction of Group 2 elements with water
8.2 The halogens
20(a) — Explain the trend in boiling points across a group of halogens
2 — Identify the correct statement about redox reactions between halogens and halide ions
21(a) — Predict and explain the colour observations from displacement reactions with halide ions
21(b) — State one benefit and one risk of using chlorine in water treatment
13 — Identify correct statements explaining the trend in boiling points down the halogens
18(b) — Write an ionic equation, with state symbols, for a described reaction step
1 — Identify which compound is present in the residue after silver halide precipitation and excess ammonia
5 — Identify the correct explanation for the trend in boiling points down the halogens
20(a)(i) — Suggest why chlorine is added to water in large-scale water treatment
20(a)(ii) — Construct an ionic equation and explain why one halogen but not another can extract a second from solution
19(d)* — Extended response: describe and explain the relative reactivity of halogens in displacement reactions
8.3 Qualitative analysis
8 — Identify which pair of solutions forms a white precipitate
7 — Identify the incorrect statement about the properties of a compound
22(a)* — Extended response: identify transition metal compounds and reactions from a series of test-tube observations Also listed under Module 5 — Transition elements
15 — Identify correct results from qualitative tests on a hydrated double salt
21(b)(ii) — Write an ionic equation, with state symbols, for a precipitation reaction
11 — Identify the correct observations from qualitative tests on two aqueous salts with acid
13 — Identify the formula of a salt from qualitative test observations
21(c)(ii) — State the purpose of adding a reagent before conducting further qualitative tests
21(c)(iii) — Predict different observations that would result from using an alternative acid in a qualitative test
21(c)(iv) — Suggest how a procedure could be modified for more reliable qualitative test conclusions
14 — Identify correct statements from qualitative tests on a transition metal solution
Enthalpy
9.1 Enthalpy changes
10 — Calculate the energy released in a reaction using enthalpy and molar gas volume data Also listed under Module 2 — Amount of substance
9 — Identify the equation representing the standard enthalpy change of atomisation of an element
17(b)(i) — Explain the term enthalpy change of formation
7 — Calculate the enthalpy change of neutralisation from given energy and mole data
1 — Identify the equation representing the enthalpy change of formation of a compound
10 — Identify the equation matching the standard enthalpy change of atomisation of an element
9.2 Measuring enthalpy changes
22(b)(ii) — Calculate an enthalpy change of neutralisation from calorimetry data
22(b)(iii) — Predict and explain the temperature change for a repeated calorimetry experiment with different volumes
17(a)(i) — Determine the maximum temperature reached in a calorimetry experiment
17(a)(ii) — Predict and explain how a modification to a method affects the maximum temperature reached
18(a) — Calculate an enthalpy change of combustion from calorimetry data
17(d)(i) — Calculate an enthalpy change of solution from calorimetry data
17(d)(ii) — Predict differences in results between two calorimetry experiments using different masses
18(a)(iii) — Calculate an enthalpy change of neutralisation from a described calorimetry method
9.3 Bond enthalpies
9 — Calculate a bond enthalpy using given enthalpy and bond enthalpy data
16(b)(i) — Explain the term average bond enthalpy
16(b)(ii) — Calculate a bond enthalpy using given thermochemical data
19(a)(i) — Explain the sign of an enthalpy change in terms of bond breaking and bond making
8 — Calculate an enthalpy change of reaction using bond enthalpy data
7 — Calculate an enthalpy change of reaction using bond enthalpy data
5 — Calculate a bond enthalpy using given enthalpy and average bond enthalpy data
9.4 Hess' law and enthalpy cycles
18(b)(iv) — Calculate an enthalpy change of formation using Hess's law and given enthalpy data
19(a)(iii) — Calculate a standard enthalpy of formation using enthalpies of combustion and Hess's law
6 — Calculate an enthalpy of combustion using enthalpies of formation
17(b)(ii) — Calculate a standard enthalpy change of formation using given data
18(b) — Calculate an enthalpy change using Hess's law and given enthalpies of combustion
5 — Calculate a standard enthalpy change of reaction using enthalpies of formation
18(c)(ii) — Calculate a standard enthalpy of formation using Hess's law
3 — Identify the change that would increase the equilibrium yield of a product
4 — Calculate the enthalpy change of a reaction using given enthalpies of formation
Reaction rates and equilibrium
10.1 Reaction rates (no questions in these papers)
10.2 Catalysts
14 — Identify correct statements explaining why reaction rate increases with temperature
7 — Identify the correct change to a Boltzmann distribution curve at a higher temperature
16(a)(i) — Explain, with a Boltzmann distribution sketch, how increasing temperature increases reaction rate
17(b) — Draw and compare a Boltzmann distribution curve at a different temperature
10.3 The Boltzmann distribution
20(b) — Complete an enthalpy profile diagram, labelling activation energies with and without a catalyst
19(c)(i) — Explain how a catalyst increases the rate of reaction, including a labelled sketch of the Boltzmann distribution 🖨️ (?)
19(c)(ii) — Explain whether a catalyst is acting homogeneously or heterogeneously
13 — Identify correct statements about the effect of a catalyst on a system at equilibrium
17(b) — State two ways that catalysts make an industrial process more sustainable
8 — Identify how a catalyst affects activation energy and the proportion of molecules that can react 🖨️ (?)
16(b)(i) — Complete an enthalpy profile diagram, labelling activation energies with and without a catalyst
16(b)(ii) — Explain why a given catalyst is described as heterogeneous 🖨️ (?)
18(a)* — Extended response: explain given statements about industrial equilibrium using chemistry principles
17(a)* — Extended response: use the Boltzmann distribution to explain a catalyst's effect on rate and its wider benefits
10.4 Dynamic equilibrium and le Chatelier's principle
20(a) — Explain, using Le Chatelier's principle, the optimum conditions for maximum yield in an industrial equilibrium
17(a) — Predict and explain the conditions of pressure and temperature for maximum equilibrium yield
9 — Identify which combination of equilibrium amounts favours the forward or reverse reaction
20(a) — State a feature of a dynamic equilibrium in a closed system
11 — Identify the point on a graph at which dynamic equilibrium is reached
18(c)(i) — Explain whether a chemist's prediction about an equilibrium change is correct
13 — Identify correct statements about a reversible reaction and its equilibrium
10.5 The equilibrium constant Kc – part 1
20(b)(i) — Write the expression and determine the units for Kc for a given equilibrium
18(a) — Write the expression and determine the units for Kc for a given equilibrium
19(b)(iv) — Explain a further property or consequence relating to the equilibrium constant
20(b) — Calculate Kc for an equilibrium from given masses and an equilibrium amount
M5Module 5 — Physical chemistry and transition elements
Rates of reactions
18.1 Orders, rate equations, and rate constants
19(c)* — Determine the order of reaction and rate constant using rate data and a graph
17(a)* — Extended response: propose a rate equation and mechanism consistent with given kinetics data
21* — Extended response: determine the initial rate, order of reaction, and rate constant from a kinetics investigation 🖨️ (?)
10 — Determine the overall order of a reaction from its rate constant units
21(a)(i) — Determine reaction orders from a rate data table
16(a)(ii) — Determine reaction orders from a table of initial rate data
17* — Extended response: determine reaction order, rate at a given time, and rate constant from a kinetics investigation
17(b)* — Determine reaction order, rate at a given time, and rate constant from a concentration–time graph 🖨️ (?)
6 — Determine the effect on rate of changing two reactant concentrations using a rate equation
19(a)* — Extended response: determine a rate constant and propose a two-step mechanism consistent with results
20(a)* — Extended response: plan an initial-rates investigation to determine a rate equation and rate constant
17(a)(i) — Calculate the rate constant, including units, for a reaction
17(a)(ii) — Calculate the rate of reaction from given reactant concentrations and a rate equation
18.2 Concentration–time graphs
10 — Identify the correct concentration–time graph shape for a zero-order reactant
19(b) — Suggest an alternative experimental method for monitoring a reaction over time 🖨️ (?)
20(a)(i) — Explain why a large excess of one reagent is used in a kinetics experiment
20(a)(ii) — Use the half-life from a graph to show that a reaction is first order
20(a)(iii) — Determine the initial rate of reaction from a concentration–time graph
8 — Calculate the rate constant for a first-order reaction from its half-life
7 — Calculate the half-life of a first-order reaction at a different starting concentration
20(d)(ii) — Explain why two reactions of a metal with different acids proceed at different rates
17(a) — Using collision theory, explain why a rate decreases over the course of a reaction
7 — Calculate the concentration remaining after multiple half-lives of a first-order reaction
6 — Calculate the half-life of a first-order reaction at a different starting concentration
5 — Identify the apparatus suitable for measuring the effect of concentration on reaction rate
18.3 Rate–concentration graphs
8 — Identify the correct rate–concentration graph shape for a first-order reactant
10 — Identify the correct rate–concentration graph shape for a zero-order reactant
18.4 Rate-determining step
21(a)(ii) — Deduce a two-step reaction mechanism consistent with a given rate equation
16(b) — Suggest a two-step mechanism consistent with a given rate equation
20(b) — Suggest a mechanism step and the resulting rate equation for a two-step reaction
7 — Determine the rate equation consistent with a proposed two-step reaction mechanism
18.5 Rate constants and temperature
17(b)(i) — Calculate the activation energy from an Arrhenius graph
17(b)(ii) — Calculate the pre-exponential factor using an Arrhenius graph
11 — Calculate the activation energy from the gradient of an Arrhenius plot
8 — Calculate the activation energy from the gradient of an Arrhenius plot
21(b)(i) — Calculate the activation energy from an Arrhenius graph
21(b)(ii) — Explain a mistake made in reading a value from an Arrhenius graph
21(b)(iii) — Determine a temperature from a given point on an Arrhenius-type graph
9 — Calculate the activation energy from the gradient of an Arrhenius plot
19(b) — Calculate the activation energy from an Arrhenius-style data table
8 — Determine the pre-exponential factor from an Arrhenius-type graph
Equilibrium
19.1 The equilibrium constant Kc – part 2
20(b)(ii) — Calculate the equilibrium amount of a product using given data
18(b) — Calculate the equilibrium amount of a product using a given value of Kc
20(a)* — Extended response: calculate an equilibrium constant and discuss industrial conditions for an equilibrium reaction
18(b) — Determine how a value of Kc changes with temperature in an industrial equilibrium
15 — Identify a source of error in a student titration used to monitor an equilibrium
19.2 The equilibrium constant Kp
13 — Calculate the partial pressure of a gas in a mixture given its mole fraction
18(b)(i) — Explain why a given equilibrium is heterogeneous
18(b)(ii) — Write the expression for Kp for a given equilibrium
9 — Calculate the partial pressure of a gas in an equilibrium mixture
19(b)(i) — Write the expression and units for Kp for a given equilibrium
19(b)(ii) — Calculate the value of Kp for an equilibrium at a given temperature
9 — Calculate the value of Kp for an equilibrium from partial pressures
17(d) — Calculate Kp for an equilibrium using the relationship between free energy change and Kp Also listed under Module 5 — Enthalpy and entropy
20(c)(i) — Calculate Kp for a gas-phase equilibrium
19(a)(i) — Calculate Kp, including its expression and units, for a gas-phase equilibrium
18(a)(i) — Calculate Kp for a gas-phase equilibrium from given equilibrium amounts
8 — Calculate the mole fraction of a gas in an equilibrium mixture
17(b) — Calculate an equilibrium composition or constant for a gas-phase reaction
12 — Identify a plausible value for an equilibrium constant given the position of equilibrium
16(c) — Calculate Kp, including units, for a gas-phase equilibrium
19.3 Controlling the position of equilibrium
18(c)(i) — Predict, with reasoning, whether a reaction is exothermic or endothermic
18(c)(ii) — Explain how the equilibrium position changes in terms of Kp
19(b)(iii) — Explain whether a temperature is higher or lower based on a comparison of Kp values
20(c)(ii) — Complete a table predicting the effect of different changes on an equilibrium system
20(b)(i) — Determine and explain whether a forward reaction is exothermic or endothermic
20(b)(ii) — Evaluate two students' conflicting explanations of a pressure change on equilibrium position
15 — Identify correct statements about a coloured gas equilibrium mixture
19(a)(ii) — Explain why it is difficult to predict the effect of combined condition changes on an equilibrium
18(a)(ii) — Explain why a higher Kp value corresponds to a higher temperature
18(a)(iii) — Predict how Kp would change if a catalyst were removed and pressure increased
8 — Determine the effect of compression on Kc and the equilibrium amount of a product
20(b)(ii) — Explain, in terms of equilibrium, why a species has different stability in acidic and alkaline conditions
16(b) — Predict the effect of increasing temperature on the composition of an equilibrium mixture
Acids, bases, and pH
20.1 Brønsted–Lowry acids and bases
21(b) — Complete an equilibrium equation and identify conjugate acid-base pairs
12 — Identify a conjugate acid–base pair from a given dissociation equation 🖨️ (?)
18(b) — Complete an equilibrium between two weak acids and label the conjugate acid-base pairs
12 — Identify the Brønsted–Lowry acids present in an acid–base equilibrium mixture
20(e)(i) — State a structural feature or definition relating to monobasic acids
20(a)(i) — Explain why the pH values of two acids of the same concentration are different
20(b) — Suggest an equilibrium equation and identify the conjugate acid-base pairs for two mixed acids
20.2 The pH scale and strong acids
12 — Calculate the hydrogen ion concentration in a mixture of two strong acids
20(a)(ii) — Calculate the pH of a strong acid solution
20.3 The acid dissociation constant Ka
19(a)(i) — Write the expression for Ka for a weak acid
19(a)(i) — Write the expression for Ka for a weak acid
19(a)(i) — Write the expression for Ka for a weak acid
9 — Calculate the hydrogen ion concentration from the pH of a weak acid solution
20.4 The pH of weak acids
21(a) — Calculate the concentration of a weak acid from its measured pH
19(a)(ii) — Calculate the pKa value of a weak acid
19(a)(iii) — Determine the percentage dissociation of a weak acid in a solution
20(a) — Calculate the pH of a weak acid solution
20(c) — Explain a discrepancy between a calculated and measured pH value for a weak acid
18(c)(i) — Show by calculation the concentration of a weak acid from its measured pH
10 — Calculate the pH of a weak acid solution from its concentration and pKa
10 — Calculate the percentage dissociation of a weak acid from its concentration and Ka
20(e)(ii) — Calculate the acid dissociation constant of a weak acid from buffer pH data
19(a)(ii) — State an approximation used to simplify an expression for Ka
19(a)(iii) — Calculate the pKa value of a weak acid using a simplified expression
20(a)(iii) — Calculate the pH of a weak acid solution
9 — Calculate the acid dissociation constant of a weak acid from its percentage dissociation
19(a)(ii) — Calculate the pKa value of a weak acid
19(a)(iii) — Calculate the pH of a solution prepared by dissolving tablets containing a weak acid
20(a) — Extended response: plan the preparation of a standard solution of a weak acid from a solid
20.5 pH and strong bases
19(b) — Determine the percentage by mass of a component in a solid product from its solution pH
20(b)(ii) — Calculate the pH of the solution at the end point of a titration
11 — Calculate the pH of the resulting mixture when an acid and base are combined
22(a) — Calculate the pH of a strong base solution
21(b)(i) — Calculate the mass of a product formed in a reaction sequence
20(a)(i) — Calculate the pH of water at a given temperature
20(a)(ii) — Explain why water is neutral at different temperatures despite different Kw values
20(b) — Write an equation and calculate the pH of a solution formed from a Group 2 metal reacting with water
10 — Identify the correct statement describing a neutral solution at any temperature
20(b) — Calculate the mass of alkali needed to prepare a solution of a target pH
19(c) — Calculate the concentration of a strong base solution from its pH
20(c)(i) — Calculate the pH of a strong base solution
Buffers and neutralisation
21.1 Buffer solutions
21(c)(i) — Determine by calculation whether a proposed method produces a target pH
21(c)(ii) — Predict and explain the effect of a volume change on the pH of a buffer solution
10 — Calculate the pH of a buffer solution prepared from a weak acid and its salt
17(a)* — Extended response: explain how a buffer system maintains pH and calculate a concentration ratio
18(c)(ii) — Calculate the concentration needed to prepare a buffer solution of a target pH
22(c)* — Extended response: determine the pH of a buffer solution prepared by a described method
19(b)(i) — Explain why a buffer solution is formed in a described mixture
19(b)(ii) — Calculate the pH of a prepared buffer solution
19(b)(iii) — Explain, in terms of equilibrium, how a buffer responds to a small addition of base
20(f) — Explain why the pH of a buffer solution does not change when a small volume of water is added
12 — Identify which solution added to a weak acid would form a buffer solution
9 — Calculate the pH of a buffer solution from a given acid-to-conjugate-base ratio
19(b)(i) — Calculate a concentration ratio using an equilibrium expression
19(b)(ii) — Calculate the mass of a salt present in a tablet
20(c)(ii) — Calculate the pH of a buffer solution
21.2 Buffer solutions in the body
22(c) — Explain, using equilibrium, how a biological buffer system maintains blood pH 🖨️ (?)
21.3 Neutralisation
20(b)(iii) — Sketch a pH curve for the titration of a weak acid with a strong base
20(b)(iv) — Explain which indicator would be most suitable for a given titration
20(b)(v) — Predict a similarity and a difference between pH curves for two different weak acids
11 — Identify the correct statement about an indicator's colour change equilibrium after a base is added
19(b)(i) — Draw a best-fit curve on a titration graph and calculate a concentration
19(b)(ii) — Identify a suitable indicator to observe the end point of a titration
Enthalpy and entropy
22.1 Lattice enthalpy
13 — Identify which listed enthalpy changes always share the same sign Also listed under Module 5 — Enthalpy and entropy
13 — Identify which listed enthalpy changes always share the same sign Also listed under Module 5 — Enthalpy and entropy
16(d)(i) — Complete a Born-Haber cycle with the species present, including state symbols
16(d)(ii) — Calculate the lattice enthalpy of a compound using a Born-Haber cycle
16(d)(i) — Complete an energy cycle with the species present, including state symbols
16(d)(iii) — Write an equation for lattice enthalpy and calculate the lattice enthalpy of a compound
16(a)(i) — Complete a Born-Haber cycle with the species present, including state symbols
16(a)(ii) — Calculate the lattice enthalpy of a compound using a Born-Haber cycle
16(c)(i) — Define the term lattice enthalpy
16(c)(ii) — Complete a Born-Haber cycle diagram with the species present
16(c)(iii) — Calculate the lattice enthalpy of a compound using a Born-Haber cycle
19(b) — Predict and explain how lattice enthalpies differ between two related ionic compounds
19(c)(ii) — Calculate the lattice enthalpy of a compound using a Born-Haber cycle
19(c)(i) — Complete a Born-Haber cycle diagram using letters representing given enthalpy changes
22.2 Enthalpy changes in solution
16(a)(i) — Explain the term enthalpy change of hydration
16(a)(ii) — Complete an energy cycle diagram with the species present, including state symbols
16(a)(iii) — Calculate an enthalpy change of hydration using an energy cycle
16(d)(ii) — Calculate an enthalpy change of hydration using a completed energy cycle
16(c)(i) — Explain what is meant by the term enthalpy change of solution
16(c)(ii) — Complete an energy cycle with the species present, including state symbols
16(c)(iii) — Calculate the enthalpy change of solution of a compound using an energy cycle
17(b) — Explain the term enthalpy change of solution
17(c)(i) — Complete an energy cycle with the species present, including state symbols
17(c)(ii) — Calculate an enthalpy change of solution using an energy cycle
18(a)(i) — Write an equation, including state symbols, for a described reaction
10 — Identify which enthalpy change is not required to calculate a lattice enthalpy
22.3 Factors affecting lattice enthalpy and hydration
16(a)(iv) — Predict and explain how the enthalpy change of hydration differs between two ions
16(e)(ii) — Explain a trend in lattice or hydration enthalpy down a group
16(c)(iv) — Explain why a trend in enthalpy change of solution down a group is difficult to predict
8 — Identify the compound requiring the most energy to form gaseous ions
17(c)(iii) — Explain the differences between enthalpy changes of hydration for a series of ions
22.4 Entropy
17(d)(i) — Write an equation and explain the entropy change for a precipitation reaction
17(d)(ii) — Write an equation and explain the entropy change for a change of state
11 — Calculate the entropy change for a reaction using standard entropy data
19(a)(ii) — Use standard entropy values to determine whether a reaction is feasible at a given temperature
17(c) — Use standard entropy values to determine whether a reaction is feasible at a given temperature
10 — Identify the signs of enthalpy and entropy change for a condensation reaction
17(c)(i) — State a definition or feature relating to entropy or feasibility
9 — Calculate a standard entropy change of formation using standard entropy data
18(c)(i) — Predict, with reasoning, the sign of an entropy change for a reaction
22.5 Free energy
18(a) — Interpret the gradient and intercepts of a graph of Gibbs free energy against temperature
18(b)(iii) — Determine the minimum temperature for a reaction to become thermodynamically feasible
17(d) — Calculate Kp for an equilibrium using the relationship between free energy change and Kp Also listed under Module 5 — Equilibrium
11 — Identify the correct combination of enthalpy and entropy signs for a reaction feasible only at high temperature
20(b)(i) — Show by calculation that a reaction is feasible at a given temperature
20(b)(ii) — Determine the maximum temperature for a reaction to remain feasible
17(c)(ii) — Calculate an enthalpy change using a given free energy change and temperature
17(c)(iii) — Explain whether a student's conclusion about reaction feasibility is correct
18(c)(ii) — Use a graph and the Gibbs equation to determine enthalpy and entropy changes for a reaction
16(a)(i) — Calculate the free-energy change of a reaction at a given temperature
16(a)(ii) — Suggest why a thermodynamically feasible reaction does not take place at a given temperature
18(c)(i) — Calculate the temperature at which a reaction's feasibility changes
18 — Calculate the free energy change of a combustion reaction using given thermodynamic data
Redox and electrode potentials
23.1 Redox reactions
12 — Determine the mole ratio of two products in a balanced redox equation
3 — Balance a redox equation and identify the correct coefficients for two species
22(d) — Construct the overall equation for a redox reaction between two transition metal species
11 — Balance a redox equation and identify the correct coefficient for a given species
20(c) — Use oxidation numbers to identify the elements oxidised and reduced in a redox reaction
21(c)(iv) — Write half-equations and an overall equation for an oxidation reaction of a complex ion
23.2 Manganate(VII) redox titrations
18(c)(ii) — Calculate the mass of an active ingredient in a tablet from titration data
22(c) — Determine the mass of a preservative in a food sample using a redox titration
21(a)(i) — State the colour change observed at the end point of a titration
21(a)(iii) — Calculate a concentration from titration results using a redox titration method
20(b)(i) — Balance a disproportionation equation using the smallest whole numbers
23.3 Iodine/thiosulfate redox titrations
20(d)(iii) — Describe and explain how to accurately determine the end point of a titration
20(d)(iv) — Determine the relative formula mass and formula of a compound from titration data
18(c) — Suggest a suitable indicator and describe its colour change for a titration
18(d) — Determine the percentage by mass of a metal in an ore using titration data
21(b) — Determine the mass of a compound in a tablet using an iodine-based titration method Also listed under Module 2 — Amount of substance
23.4 Electrode potentials
14 — Identify correct statements about a cell constructed from two given redox systems
22(a)(i) — Draw a labelled diagram of the apparatus needed to measure a standard cell potential
22(a)(ii) — Calculate the standard cell potential of a given cell
21(b)(i) — Draw a labelled diagram of the apparatus needed to measure a standard cell potential
21(b)(ii) — Calculate the standard cell potential of a given cell
19(a) — Draw a labelled diagram of a standard cell to measure its standard cell potential
19(a)(i) — Draw a labelled diagram of a standard cell to measure its standard cell potential 🖨️ (?)
19(a)(ii) — Construct the equation for the overall cell reaction
19(c)(ii) — Calculate the electrode potential of the negative electrode of a cell
21(c) — Draw a labelled diagram of the apparatus needed to measure a standard electrode potential
13 — Determine the overall cell reaction from two given standard electrode potentials
11 — Identify the correct statement about a standard cell from two given electrode potentials
21(a)(i) — Outline an experimental setup to measure the standard cell potential of an electrochemical cell 🖨️ (?)
21(a)(ii) — State and explain the effect of a concentration change on the potential of an electrochemical cell
23.5 Predictions from electrode potentials
22(b) — Identify the strongest reducing agent and strongest oxidising agent from a table of electrode potentials 🖨️ (?)
22(c) — Construct an overall equation for a predicted redox reaction using electrode potential data
21(c)(i) — Write the overall equation for a redox reaction between two given species
21(c)(ii) — Explain a redox reaction sequence in terms of electrode potentials and equilibria
18(b)(ii) — Use electrode potential data to explain a sequence of colour changes
18(b)(iii) — Construct an equation for a colour-change redox reaction
19(b) — Explain an observed reaction in terms of electrode potentials and equilibria
19(c) — Deduce a missing electrode potential from a fuel cell's given overall cell potential
12 — Identify the strongest oxidising agent from two given redox systems
19(b)(ii) — Explain, using electrode potentials and equilibrium shifts, why a species disproportionates in acid
22(b)(ii) — Use electrode potential data to explain and construct an equation for a colour change on standing in air
21(b) — Determine the combined concentration of two oxidation states of an ion using a described method
21(b) — Predict which oxidising agents from a table would not oxidise a given ion
21(c) — Determine the formulae of products formed from a redox reaction using electrode potential data
23.6 Storage and fuel cells
12 — Determine the overall cell reaction equation from two half-equations
15 — Identify correct statements about the electrode reactions in an alkaline fuel cell
19(c)(i) — Write the half-equation at the negative electrode of a cell
19(c)(iii) — State a feature of a fuel cell that differs from a conventional storage cell
12 — Identify the correct statement about a cell constructed from two given half-cells
21(d)(i) — Construct the overall cell equation for a given commercial cell
21(d)(ii) — Show that the standard cell potential and overall equation are the same for a fuel cell in acidic and alkaline conditions
20(c) — Determine a missing electrode potential for a fuel cell operating in acidic or alkaline conditions
Transition elements
24.1 d-block elements
21(a) — Complete the electron configuration of a transition metal atom and its ion Also listed under Module 5 — Transition elements
21(a) — Complete the electron configuration of a transition metal atom and its ion Also listed under Module 5 — Transition elements
14 — Identify correct properties of a transition element
18(b)(i) — Complete the electron configuration of a transition metal ion Also listed under Module 5 — Transition elements
18(b)(i) — Complete the electron configuration of a transition metal ion Also listed under Module 5 — Transition elements
5 — Identify the correct statement about d-block elements in Period 4
17(a) — Explain, using electron configurations, why two elements are d-block but not transition elements
15 — Identify which ions contain one or more unpaired electrons
22(a)* — Extended response: explain, using electron configurations, why some d-block elements are not transition elements
15 — Identify correct statements about the organisation of elements in the periodic table
21(a) — Complete the electron configurations of a transition metal atom and its ion
12 — Identify the reason why a given element is not classified as a transition element
15 — Identify correct statements about the properties and reactions of a transition metal ion
21(a)(i) — Complete the electron configuration of a transition metal ion
24.2 The formation and shapes of complex ions
2 — Identify the type of bonding between ligands and the metal ion in a complex ion 🖨️ (?)
18(a)(iii) — Draw a 3D diagram for the shape of a complex ion formed in an experiment
22(b)(i) — Calculate unknown stoichiometric values in the formula of a compound
17(b)(i) — State what is meant by the term bidentate ligand
6 — Determine the number of two oxidation states of an ion in the formula of a compound
22(a)(i) — Explain why a given ligand can act as a bidentate ligand
22(c) — Determine the charge and coordination number of a complex ion from its ligands
22(b)(ii) — Determine the formula and charge of an octahedral complex ion from its molar mass
21(c)(ii) — Show the bond angles on a diagram of a complex ion
13 — Identify the correct statement about the shape or properties of a complex ion
24.3 Stereoisomerism in complex ions
23(b)* — Determine the formula of a hydrated complex from mass loss data on heating
15 — Identify correct statements about the structure and properties of a square planar complex
13 — Determine the number of stereoisomers a given complex ion can form
15 — Identify correct statements about the isomerism and coordination of a complex ion
17(b)(ii)* — Extended response: determine complex ion formulae, write a ligand substitution equation, and draw stereoisomers
22(a)(ii) — Determine the empirical formula and charge of a complex ion with given ligands
14 — Identify correct statements about the structure and isomerism of an anti-cancer complex
21(b) — Draw and label the 3D structures of two stereoisomers of a complex ion
22(b)* — Extended response: describe the shapes and stereoisomerism found in transition metal complexes
24.4 Ligand substitution and precipitation
11 — Identify the product formed when a transition metal ion reacts with excess aqueous sodium hydroxide
23(a)(i) — Identify the formulae of species responsible for observations in qualitative tests
23(a)(ii) — Name the type of reaction occurring in two given qualitative tests
21(d)* — Extended response: identify and explain the reactions, isomerism, and colour changes of transition metal complexes 🖨️ (?)
17(b) — Explain, using ligand substitution, how a biological molecule transports oxygen and why a toxic gas interferes
18(a)(i) — Identify the formula of a complex ion formed in a described experiment
18(a)(ii) — Suggest an equation, including state symbols, for a described experimental step
18(a)(iv) — Identify the formula of an ion responsible for a colour change in an experiment
18(a)(v) — State the colour of a solution formed in a described experimental step
22(a)* — Extended response: identify transition metal compounds and reactions from a series of test-tube observations Also listed under Module 3 — Reactivity trends
22(b)(i) — Write an ionic equation for the formation of a coloured precipitate
22(c)* — Extended response: identify transition metal complex ions and reactions from a series of described experiments
22(b)(i) — Describe a precipitation reaction of a transition metal ion, including an equation
22(b)(ii) — Describe a ligand substitution reaction of a transition metal ion, including an equation
22(b)(i) — Suggest the formulae of species formed in a sequence of transition metal reactions
21(c)(i) — Identify unknown ions and construct ionic equations from a series of test-tube observations
21(a)(ii) — Complete a flowchart of reactions using formulae for reagents and products
21(c)(i) — Write the equation and identify the reaction type for a ligand substitution
22(a) — Determine the formulae of transition metal species formed in a described reaction sequence
24.5 Redox and qualitative analysis (no questions in these papers)
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