Practical skills — AS & A Level Chemistry (9701) questions by topic
Titration and gravimetric methods define this topic: determining a metal's relative atomic mass via carbonate titration, measuring hydrogen peroxide concentration through oxygen evolved, and calculating iron content in a supplement tablet by titration.
Calculate, suggest, explain, state and describe are the command words across 106 questions, by far the most in this syllabus set, drawn from 2023 to 2025 papers and worth between 7 and 23 marks. Because these are extended practical write-ups, drafting a full method and calculation for instant marking shows exactly where a significant-figure slip or an unrinsed beaker cost accuracy marks, before the same habit repeats across a whole practical paper.
What examiners look for
- Examiners repeatedly note candidates altering results when a final mass appeared greater than the original, rather than recognising this was due to adding the catalyst.
- A common mistake was subtracting the initial mass of flask and solution from the final mass of flask and contents.
- Reports flag very few candidates noticing the rapid gas evolution on adding MnO2, and a common misconception that the cotton wool plug prevents oxygen escaping rather than reducing frothing loss.
- Strong scripts completed the titration accurately, recorded burette readings in correctly labelled tables, and generated a correct average titre.
- Candidates who gave answers to an appropriate number of significant figures and constructed the ionic equation with correct state symbols tended to score well.
May–June 2025, Paper 31
You will determine the percentage purity of a sample of impure calcium carbonate, FA 1, by reacting it with excess hydrochloric acid and measuring the volume of carbon dioxide…
Answer this question and get it marked →You will determine the percentage purity of another sample of calcium carbonate, CaCO3, by titration. FA 3 has been prepared by reacting 19.0 g of FA 1 with 250 cm3 of 2.00 mol…
Answer this question and get it marked →FA 7 is a solution containing two cations and one anion. All of the ions are listed in the Qualitative analysis notes. (i) Carry out the following tests and record your…
Answer this question and get it marked →May–June 2025, Paper 32
In this experiment you will carry out a titration to determine the proticity of citric acid, C6H8O7. FB 1 is aqueous citric acid containing 7.50 g dm-3 C6H8O7. FB 2 is aqueous…
Answer this question and get it marked →You will determine the enthalpy change for the reaction of aqueous citric acid with aqueous sodium hydroxide to form aqueous sodium citrate. FB 4 and FB 5 are both citric acid,…
Answer this question and get it marked →Solutions FB 7 and FB 8 each contain one cation and one anion. All of the ions are listed in the Qualitative analysis notes. (i) Carry out the following tests and record your…
Answer this question and get it marked →May–June 2025, Paper 33
You will carry out a titration to determine the concentration of hydrogen peroxide, H2O2, in solution FA 1. The reaction of hydrogen peroxide with acidified potassium permanganate…
Answer this question and get it marked →In this question you will use the calorimetric method to determine the concentration of H2O2 in FA 1. Manganese(IV) oxide, MnO2 (FA 5), acts as a catalyst for the decomposition of…
Answer this question and get it marked →FA 2 is aqueous potassium permanganate, KMnO4. FA 5 is manganese(IV) oxide, MnO2. FA 6 is aqueous iron(III) chloride, FeCl3. (i) Use a spatula to transfer a small amount of FA 5…
Answer this question and get it marked →May–June 2025, Paper 34
Iron is an element that is essential in the human diet. Some people need to take iron supplement tablets to ensure an adequate intake of iron. You will investigate the mass of…
Answer this question and get it marked →The reaction between an acid and an alkali is exothermic. You will carry out a neutralisation experiment to determine the enthalpy change involved. You will mix different volumes…
Answer this question and get it marked →FB 6, FB 7 and FB 8 are aqueous solutions of different compounds that each contain at least one oxygen atom. (i) Carry out the following tests and record your observations in…
Answer this question and get it marked →May–June 2025, Paper 35
Group 1 metal carbonates react with dilute acids to form a salt, water and carbon dioxide. The identity of the metal, M, can be determined by measuring the volume of carbon…
Answer this question and get it marked →The identity of a Group 1 metal in a metal carbonate may also be determined by titration with acid. Z2CO3 is a Group 1 metal carbonate. The metal may or may not be the same as…
Answer this question and get it marked →FA 6 and FA 7 are aqueous solutions that each contain one cation and one anion. All the ions are listed in the Qualitative analysis notes. None of the ions contains nitrogen. (i)…
Answer this question and get it marked →May–June 2025, Paper 37
Hydrogen peroxide, H2O2, reacts rapidly with acidified potassium manganate(VII), KMnO4: 5H2O2(aq) + 2MnO4-(aq) + 6H+(aq) → 5O2(g) + 8H2O(l) + 2Mn2+(aq) You will determine the…
Answer this question and get it marked →You will now determine the concentration of a solution of hydrogen peroxide by a different method. Hydrogen peroxide decomposes slowly into water and oxygen at room temperature.…
Answer this question and get it marked →FA 2 is KMnO4(aq). FA 5 is MnO2. (i) Transfer a 2 cm depth of FA 2, KMnO4, into a test-tube. Add the same volume of aqueous sodium hydroxide followed by a small spatula measure of…
Answer this question and get it marked →May–June 2025, Paper 38
Iron is an element that is essential in the human diet. Some people need to take iron supplement tablets to ensure an adequate intake of iron. You will investigate the mass of…
Answer this question and get it marked →The reaction between an acid and an alkali is exothermic. You will carry out a neutralisation experiment to determine the enthalpy change involved. You will mix different volumes…
Answer this question and get it marked →FB 6, FB 7 and FB 8 are aqueous solutions of different compounds that each contain at least one oxygen atom. (i) Carry out the following tests and record your observations in…
Answer this question and get it marked →May–June 2025, Paper 51
Grignard reagents have the general formula RMgX, where R is a hydrocarbon group and X is a halogen. The Grignard reagent C₆H₅MgBr is used as an intermediate in the reaction…
Answer this question and get it marked →May–June 2025, Paper 52
Activated carbon is a form of carbon with the ability to adsorb solutes from solutions. The adsorption of ethanedioic acid molecules, (COOH)₂, from dilute ethanedioic acid,…
Answer this question and get it marked →The enthalpy change of combustion, ΔHc, of butane, C₄H₁₀, can be determined using the apparatus shown in Fig. 2.1 (metal can of water heated by a gas burner). Steps: 1. Use a 500…
Answer this question and get it marked →May–June 2025, Paper 53
Grignard reagents have the general formula RMgX, where R is a hydrocarbon group and X is a halogen. The Grignard reagent C₆H₅MgBr is used as an intermediate in the reaction…
Answer this question and get it marked →May–June 2025, Paper 54
The relative molecular mass, Mr, of an unknown volatile liquid, Y, can be determined experimentally. A student determines the volume of a conical flask by the following steps:…
Answer this question and get it marked →A student carries out an experiment to determine the charge of an aqueous ion, Mⁿ⁺(aq), of metal M. The student prepares 100.0 cm³ of 1.00 mol dm⁻³ aqueous copper(II) nitrate,…
Answer this question and get it marked →May–June 2024, Paper 31
In this experiment you will determine the enthalpy change, ΔHr, for the reaction shown. NaOH(aq) + CO2(g) → NaHCO3(aq) enthalpy change = ΔHr You will react each of sodium…
Answer this question and get it marked →Sodium sulfite is oxidised when it reacts with excess iodine. Na2SO3(aq) + I2(aq) + H2O(l) → Na2SO4(aq) + 2HI(aq) The remaining iodine is then titrated using aqueous sodium…
Answer this question and get it marked →FA 7, FA 8 and FA 9 are dilute ethanoic acid, dilute hydrochloric acid and aqueous silver nitrate but not necessarily in that order. The solutions of acids have equal…
Answer this question and get it marked →May–June 2024, Paper 32
Students are told to plan and carry out an experiment to determine the enthalpy change, ΔH1, when one mole of anhydrous sodium thiosulfate, Na2S2O3, is hydrated. Na2S2O3(s) +…
Answer this question and get it marked →Iodate ions contain iodine and oxygen. They have the formula IOx⁻ where x is an integer. In this experiment you will determine the value of x in an iodate. You will first react…
Answer this question and get it marked →FB 7 is an aqueous solution of a salt containing one cation and one anion, both of which are listed in the Qualitative analysis notes. Carry out the following tests using a 1 cm…
Answer this question and get it marked →May–June 2024, Paper 33
When ammonium compounds are heated with sodium hydroxide or calcium hydroxide, ammonia is liberated. The ionic equation for the reaction is shown. NH4⁺ + OH⁻ → NH3 + H2O FA 1 is…
Answer this question and get it marked →A sample of ammonium bromide has been accidentally mixed with another salt. A student suggests that the percentage purity of the ammonium bromide can be determined by measuring…
Answer this question and get it marked →FA 5 is a mixture containing two cations and two anions. Three of the ions are listed in the Qualitative analysis notes. Carry out the following tests and record your observations…
Answer this question and get it marked →May–June 2024, Paper 34
Method: Fill the burette with FB 2. Pipette 25.0 cm3 of FB 3 into a conical flask. Add a few drops of FB 4 to the conical flask. Perform a rough titration and record your burette…
Answer this question and get it marked →Method and Results: record the mass of empty crucible and lid; mass of crucible, lid and FB 1 (before heating); mass of crucible, lid and FB 1 (after first heating); mass of…
Answer this question and get it marked →FB 5 is a compound containing one cation and one anion, both of which are listed in the Qualitative analysis notes. (i) Heat a small spatula measure of FB 5 in a hard-glass…
Answer this question and get it marked →May–June 2024, Paper 35
Method and Results: carry out Experiment 1 and Experiment 2 as described, and use rate = 1000 / reaction time to calculate the rate of reaction. Record all your data in a table.…
Answer this question and get it marked →Method and Results: carry out the experiment as described and record all temperature and mass readings, including the temperature of the water every half minute from t = 0 to t =…
Answer this question and get it marked →FA 6 is a salt containing a Group 1 ion and an anion that consists of a transition metal and a non-metal element. (i) Transfer FA 6 into a hard-glass test-tube. Heat the tube…
Answer this question and get it marked →May–June 2024, Paper 51
Aqueous sodium thiosulfate can be prepared from Na2S2O3.5H2O(s). (i) Determine the mass, in g, of Na2S2O3.5H2O(s) required to prepare 500.0 cm3 of 0.00200 mol dm-3 Na2S2O3(aq).…
Answer this question and get it marked →Suggest a reason why it is necessary to wait for 10 minutes in step 5.
Answer this question and get it marked →May–June 2024, Paper 52
Calcium carbonate, CaCO3(s), decomposes when heated, as shown. CaCO3(s) - CaO(s) + CO2(g) The enthalpy change of reaction, delta-H r, for the thermal decomposition of CaCO3(s)…
Answer this question and get it marked →This question is about an experiment to investigate the effect of temperature on the equilibrium constant, K1, of the reaction shown. Fe3+(aq) + SCN-(aq) <= FeSCN2+(aq) The data…
Answer this question and get it marked →May–June 2024, Paper 53
Titration can be used to determine the concentration of dissolved oxygen in samples of river water. Procedure: step 1 - use five 50 cm3 graduated syringes, A, B, C, D and E, to…
Answer this question and get it marked →The activation energy, EA, for the reaction between dilute hydrochloric acid, HCl(aq), and aqueous sodium thiosulfate, Na2S2O3(aq), can be determined by an initial rates method.…
Answer this question and get it marked →October–November 2024, Paper 31
The neutralisation of an acid by an alkali is an exothermic reaction. The concentration of an acid can be found by measuring the temperature change when the acid reacts with an…
Answer this question and get it marked →Acids react with carbonates to produce carbon dioxide gas: Na₂CO₃(s) + H₂SO₄(aq) → Na₂SO₄(aq) + CO₂(g) + H₂O(l). This reaction can be used to determine the concentration of acid,…
Answer this question and get it marked →FA 4, FA 5 and FA 6 are compounds of the same metal in different oxidation states. Place a small spatula measure of FA 4 in a hard-glass test-tube. Heat the tube gently at first…
Answer this question and get it marked →October–November 2024, Paper 33
When a metal carbonate reacts with a suitable acid, carbon dioxide is produced. You will determine the relative formula mass, Mr, of a metal carbonate by reacting it with excess…
Answer this question and get it marked →The relative formula mass, Mr, of metal carbonate FA 1 can also be determined by titration of a solution of FA 1 with an acid such as hydrochloric acid: CO₃²⁻(aq) + 2H⁺(aq) →…
Answer this question and get it marked →FA 6 contains one cation and one anion both of which are listed in the Qualitative analysis notes. Heat a small spatula measure of FA 6 in a hard-glass test-tube until no further…
Answer this question and get it marked →October–November 2024, Paper 34
Iodine reacts with propanone in the presence of an acid catalyst. The rate can be measured by determining how the concentration of iodine changes with time: CH₃COCH₃(aq) + I₂(aq)…
Answer this question and get it marked →In this experiment you will identify the ions in the hydrated salt MA₂•2H₂O, where M is a Group 2 metal. You will first determine the relative formula mass of the salt by…
Answer this question and get it marked →FB 6 is potassium manganate(VII). Place all the FB 6 in a hard-glass test-tube and heat gently at first and then more strongly. Record your observations. Leave the tube to cool…
Answer this question and get it marked →October–November 2024, Paper 35
The neutralisation of an acid by an alkali is an exothermic reaction. The concentration of an acid can be found by measuring the temperature change when the acid reacts with an…
Answer this question and get it marked →Acids react with carbonates to produce carbon dioxide gas: Na₂CO₃(s) + H₂SO₄(aq) → Na₂SO₄(aq) + CO₂(g) + H₂O(l). This reaction can be used to determine the concentration of acid,…
Answer this question and get it marked →FA 4, FA 5 and FA 6 are compounds of the same metal in different oxidation states. Place a small spatula measure of FA 4 in a hard-glass test-tube. Heat the tube gently at first…
Answer this question and get it marked →October–November 2024, Paper 36
Sodium carbonate reacts with hydrochloric acid to release carbon dioxide as shown. Na2CO3(s) + 2HCl(aq) - 2NaCl(aq) + CO2(g) + H2O(l) You will find the percentage purity in a…
Answer this question and get it marked →Many metal carbonates, such as magnesium carbonate, decompose to form the metal oxide when heated. MgCO3(s) - MgO(s) + CO2(g) Other metal carbonates, such as sodium carbonate,…
Answer this question and get it marked →FB 4 is a mixture of two salts that each contain one cation and one anion. All the ions present are in the Qualitative analysis notes. (a) Place a small spatula measure of FB 4…
Answer this question and get it marked →October–November 2024, Paper 51
A student uses the following method to determine the percentage by mass of the painkiller aspirin, C9H8O4(s), in some tablets. step 1: Grind five tablets into a powder. step 2:…
Answer this question and get it marked →October–November 2024, Paper 52
Solution X is dilute hydrochloric acid of unknown concentration. A student uses titration with aqueous sodium carbonate, Na2CO3(aq), to determine the concentration of solution X.…
Answer this question and get it marked →A group of students uses the following method to investigate the change in mass that takes place when metal M combines with sulfur to form a metal sulfide. step 1: Weigh a clean…
Answer this question and get it marked →October–November 2024, Paper 53
Alkaline aqueous iodine is irritating to the skin and eyes. Identify an appropriate precaution, other than eye protection and a lab coat, that the student should take when using…
Answer this question and get it marked →Using the absorbance-against-wavelength graph in Fig. 2.1, suggest the best wavelength of light to use in the colorimeter when measuring the concentration of C25H30N3Cl(aq).
Answer this question and get it marked →February–March 2023, Paper 33
Some metal carbonates occur in a basic form which means that the metal hydroxide is also present. The formula of one form of basic zinc carbonate is ZnCO3•2Zn(OH)2•xH2O, where x…
Answer this question and get it marked →In this experiment you will determine the relative formula mass, Mr, of basic zinc carbonate, ZnCO3•2Zn(OH)2•xH2O, by an alternative method. A known mass of basic zinc carbonate…
Answer this question and get it marked →FA 5 contains one cation and one anion, both of which are listed in the Qualitative analysis notes. FA 5 is insoluble in water. (FA 5 is copper(II) carbonate, CuCO3.) Transfer…
Answer this question and get it marked →February–March 2023, Paper 52
The student records their titration results in Table 1.1 (rough, titration 1, titration 2, titration 3): final burette readings 10.60, 20.35, 30.25, 9.85 cm³; initial burette…
Answer this question and get it marked →May–June 2023, Paper 31
Quantitative Analysis. The thiosulfate ion, S2O3^2-, decomposes when an acid is added: S2O3^2-(aq) + 2H+(aq) - S(s) + SO2(aq) + H2O(l). The rate of this reaction can be…
Answer this question and get it marked →Many salts contain water of crystallisation which can be removed by heating to form the anhydrous salt. You will determine the enthalpy change of dehydration for hydrated…
Answer this question and get it marked →Qualitative analysis. A student finds a container of a compound thought to be FA 3 and labels it FA 5. (FA 5 is in fact ZnSO4.7H2O.) Carry out tests to determine whether your…
Answer this question and get it marked →May–June 2023, Paper 32
In this experiment you will determine the relative atomic mass, Ar, of metal M by thermal decomposition of its basic carbonate, MCO₃·M(OH)₂. FB 1 is the basic metal carbonate,…
Answer this question and get it marked →In this experiment you will determine the relative atomic mass, Ar, of another metal, X, by a titration method using the metal carbonate, X₂CO₃. FB 2 is 0.0460 mol dm⁻³…
Answer this question and get it marked →May–June 2023, Paper 33
A redox reaction takes place between hydroxylamine, NH₂OH, and the iron(III) ion, Fe³⁺, in acidic conditions. The iron(III) ion is reduced to an iron(II) ion, Fe²⁺. The reaction…
Answer this question and get it marked →The reaction between thiosulfate ions and hydrogen ions produces a precipitate of sulfur. When the concentration of hydrogen ions, [H⁺(aq)], is kept constant, the rate is…
Answer this question and get it marked →May–June 2023, Paper 34
You will investigate the enthalpy change of neutralisation, ΔHneut, between aqueous sodium hydroxide of known concentration and a dilute organic acid. You will use your results to…
Answer this question and get it marked →A gravimetric procedure can identify the metal in many metal carbonates. You will decompose a metal carbonate, MCO₃, by heating to produce the metal oxide and carbon dioxide. You…
Answer this question and get it marked →May–June 2023, Paper 35
Magnesium is a reactive metal which corrodes when left in air. Magnesium reacts with acid to release hydrogen. You will determine the percentage purity of a sample of magnesium by…
Answer this question and get it marked →In Question 1 you determined the percentage purity of a sample of magnesium by measuring the volume of gas produced when it reacts with an acid. In Question 2 you will use the…
Answer this question and get it marked →May–June 2023, Paper 51
State whether beaker A in step 7 contains the aqueous layer or the ethoxyethane layer. Explain your answer.
Answer this question and get it marked →Suggest why each sample is applied to the chromatography paper using a thin capillary tube rather than a dropping pipette.
Answer this question and get it marked →The scientist is given 1.02 g of an aromatic diazonium compound in a 50 cm3 beaker. Describe the steps the scientist should take to make a 100.0 cm3 standard solution containing…
Answer this question and get it marked →May–June 2023, Paper 52
Calculate the volume of methyl benzoate used in step 1. Give your answer to the nearest 0.05 cm3. Density of methyl benzoate is 1.08 g cm-3.
Answer this question and get it marked →May–June 2023, Paper 53
State whether beaker A in step 7 contains the aqueous layer or the ethoxyethane layer. Explain your answer.
Answer this question and get it marked →Suggest why each sample is applied to the chromatography paper using a thin capillary tube rather than a dropping pipette.
Answer this question and get it marked →The scientist is given 1.02 g of an aromatic diazonium compound in a 50 cm3 beaker. Describe the steps the scientist should take to make a 100.0 cm3 standard solution containing…
Answer this question and get it marked →October–November 2023, Paper 31
Quantitative analysis. You will determine the value of x in hydrated sodium carbonate, Na2CO3.xH2O. x is not an integer. You will carry out two methods to determine the value of…
Answer this question and get it marked →Qualitative analysis. FA 6, FA 7 and FA 8 are salts each of which contains nitrogen. Each of the nitrogen-containing ions is different and all are shown in the Qualitative…
Answer this question and get it marked →October–November 2023, Paper 33
Quantitative Analysis. You will carry out a titration to determine the concentration of a solution of potassium manganate(VII), KMnO4. Potassium manganate(VII) reacts with excess…
Answer this question and get it marked →You will determine the enthalpy change for the reaction of magnesium oxide with water to form magnesium hydroxide: MgO(s) + H2O(l) - Mg(OH)2(s). The procedure involves two…
Answer this question and get it marked →Qualitative Analysis. FA 9 contains one cation and one anion. The cation is one of calcium, magnesium, manganese(II) or zinc. The anion is oxide or carbonate. Describe reactions…
Answer this question and get it marked →October–November 2023, Paper 34
Iron(III) ions, Fe³⁺, can oxidise iodide ions, I⁻, to iodine, I₂: 2Fe³⁺(aq) + 2I⁻(aq) → 2Fe²⁺(aq) + I₂(aq). The rate of this reaction can be determined by measuring the time to…
Answer this question and get it marked →In this experiment you will determine the relative formula mass of an unknown ion, A²⁻, present in a salt with the formula Na₂A•5H₂O. You will first determine the enthalpy change…
Answer this question and get it marked →October–November 2023, Paper 35
You will determine the value of x in hydrated sodium carbonate, Na₂CO₃•xH₂O (x is not an integer), by two methods, each involving sodium carbonate reacting with excess…
Answer this question and get it marked →October–November 2023, Paper 36
When hydrogen peroxide is decomposed by a suitable catalyst, oxygen and water are produced. You will determine the concentration of a solution of hydrogen peroxide by decomposing…
Answer this question and get it marked →The concentration of a solution of hydrogen peroxide can also be determined by titration with acidified potassium manganate(VII): 2MnO₄⁻(aq) + 5H₂O₂(aq) + 6H⁺(aq) → 2Mn²⁺(aq) +…
Answer this question and get it marked →October–November 2023, Paper 51
The concentration of dissolved oxygen in a sample of water can be measured using the following method. Manganese(II) hydroxide, Mn(OH)2, is oxidised by the oxygen dissolved in a…
Answer this question and get it marked →Benzenediazonium chloride, C6H5N2Cl, decomposes in water as shown in the following equation. C6H5N2Cl(aq) + H2O(l) - C6H5OH(aq) + N2(g) + HCl(aq) A solution of 0.0750 mol dm^-3 of…
Answer this question and get it marked →October–November 2023, Paper 52
Thermometric titrations can be used to determine the standard enthalpy change of neutralisation. The maximum temperature reached in a thermometric titration occurs at the point of…
Answer this question and get it marked →A student investigates the rate of reaction when zinc reacts with dilute hydrochloric acid, HCl(aq). Zn(s) + 2HCl(aq) - ZnCl2(aq) + H2(g) Method: Step 1 - accurately weigh 1.00 g…
Answer this question and get it marked →October–November 2023, Paper 53
The concentration of dissolved oxygen in a sample of water can be measured using the following method. Manganese(II) hydroxide, Mn(OH)2, is oxidised by the oxygen dissolved in a…
Answer this question and get it marked →Benzenediazonium chloride, C6H5N2Cl, decomposes in water as shown in the following equation. C6H5N2Cl(aq) + H2O(l) - C6H5OH(aq) + N2(g) + HCl(aq) A solution of 0.0750 mol dm^-3 of…
Answer this question and get it marked →Other AS & A Level Chemistry topics
- Hydrocarbons (65)
- Chemical bonding (63)
- The Periodic Table: chemical periodicity (59)
- Chemical energetics (53)
- Equilibria (53)
- Introduction to organic chemistry (53)
- Reaction kinetics (52)
- Carboxylic acids and derivatives (52)
- Group 2 (51)
- Carbonyl compounds (45)
- Atomic structure (44)
- Halogen compounds (37)