plumiEnergetics I: Edexcel A‑Level Chemistry questions
Every Edexcel A-Level Chemistry exam question on 8 Energetics I, 2016–2025, with its mark scheme and examiner’s report.
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Calculations
Q3(a)
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Q3(b)(i)
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Q3(b)(iii)
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Q3(b)(iv)
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Q3(b)(v)
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Q3(a)
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Q3(b)
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Q3(c)
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Q3(d)
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Q4(b)
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Q9(a)(i)
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Q9(a)(ii)
The whole paper ↗![June 2025 AS Paper 2, question 9(a)(ii): Calculate the enthalpy change for the formation of butane gas from its elements, using the information provided. ΔcH d [C(graphite/s)] = –394 kJ mol–1 ΔcH d [H2](https://pub-e8a9dbab8e2a4d089f52b2a45e0d0b50.r2.dev/bank/8ch002-jun25-09-aii-qp.webp)
Q9(b)
The whole paper ↗![June 2025 AS Paper 2, question 9(b): State the relevant conditions indicated by the standard symbol in the expression for the standard enthalpy change of combustion of butane, ΔcH d [butane]. (2)](https://pub-e8a9dbab8e2a4d089f52b2a45e0d0b50.r2.dev/bank/8ch002-jun25-09-b-qp.webp)
Q5(a)
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Q5(b)(i)
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Q5(b)(ii)
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Q5(c)
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Q4(a)(i)
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Q4(a)(ii)
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Q4(b)(i)
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All 110 questions on Energetics I, as a list
- June 2025, Paper 1, Q3(a) (1 mark): State why the enthalpy change for the thermal decomposition of calcium carbonate cannot be determined directly. (1)
- June 2025, Paper 1, Q3(b)(i) (1 mark): Complete the missing data in the table for Reaction 2. (1) Measurement Value Mass of weighing boat with calcium carbonate / g 4.30 Mass of weighing boat after e
- June 2025, Paper 1, Q3(b)(iii) (3 marks): Calculate the enthalpy change, ΔrH2 , for Reaction 2 in kJ mol–1. Include a sign in your answer. [Assume the specific heat capacity of the solution = 4.18 J g–1
- June 2025, Paper 1, Q3(b)(iv) (2 marks): The student carried out a similar procedure with calcium oxide. The enthalpy change, ΔrH3 , calculated for Reaction 3 was –176.3 kJ mol–1. Reaction 3: CaO(s) +
- June 2025, Paper 1, Q3(b)(v) (1 mark): Calculate a value for the enthalpy change ΔrH1 for the thermal decomposition of calcium carbonate by using your cycle. (1)
- June 2025, AS Paper 2, Q3(a) (1 mark): Predict the enthalpy change of combustion of hexan‑1‑ol, C6H13OH. (1) kJ mol–1
- June 2025, AS Paper 2, Q3(b) (4 marks): The enthalpy change of combustion of octan‑1‑ol can be determined using the equipment shown in the diagram. Procedure A spirit burner was filled with liquid oct
- June 2025, AS Paper 2, Q3(c) (2 marks): In the experiment, the calorimeter is not insulated. Explain the difference between the enthalpy change of combustion of octan‑1‑ol determined in this experimen
- June 2025, AS Paper 2, Q3(d) (2 marks): A student carried out this experiment leaving the thermometer at the bottom of the calorimeter and not stirring. Explain the effect this would have on the calcu
- June 2025, AS Paper 2, Q4(b) (2 marks): Butan-1-ol can also be produced from the reaction of water with 1-bromobutane. Draw a fully labelled enthalpy level diagram for this endothermic reaction. Inclu
- June 2025, AS Paper 2, Q9(a)(i) (4 marks): Complete an enthalpy cycle for these reactions including relevant arrows, labels, species and state symbols. (4) C4H10(g) + 6½O2(g) 4CO2(g) + 5H2O(l)
- June 2025, AS Paper 2, Q9(a)(ii) (3 marks): Calculate the enthalpy change for the formation of butane gas from its elements, using the information provided. ΔcH d [C(graphite/s)] = –394 kJ mol–1 ΔcH d [H2
- June 2025, AS Paper 2, Q9(b) (2 marks): State the relevant conditions indicated by the standard symbol in the expression for the standard enthalpy change of combustion of butane, ΔcH d [butane]. (2)
- June 2024, Paper 1, Q5(a) (3 marks): Calculate the enthalpy change for the reaction using the mean bond enthalpy data. (3) Bond Mean bond enthalpy / kJ mol−1 C C 347 C H 413 C O 358 O H 464 O O 498
- June 2024, Paper 1, Q5(b)(i) (2 marks): Complete the enthalpy cycle for the overall reaction in the Direct Ethanol Fuel Cell. Include labels. (2) ΔfH / kJ mol−1 Substance C2H5OH(l) −277 CO2(g) −394 H2
- June 2024, Paper 1, Q5(b)(ii) (1 mark): Calculate a value for the enthalpy change of the Direct Ethanol Fuel Cell reaction, using your cycle. (1) Enthalpy change = kJ mol−1
- June 2024, Paper 1, Q5(c) (2 marks): Give two reasons for the difference between your calculated values in (a) and (b). (2)
- June 2024, AS Paper 2, Q4(a)(i) (3 marks): Some mean bond enthalpy values are given in the table. Mean bond enthalpy / kJ mol–1 Bond C H 413 C C 347 C C 612 Calculate the enthalpy change of this dimerisa
- June 2024, AS Paper 2, Q4(a)(ii) (2 marks): A different value for the enthalpy change of the reaction can be calculated using bond enthalpies instead of mean bond enthalpies. This value is more accurate.
- June 2024, AS Paper 2, Q4(b)(i) (4 marks): Complete the enthalpy cycle using Hess’s Law. Include reactants, products, state symbols and arrows in your cycle. (4) ΔfH C4H8(g) + +
- June 2024, AS Paper 2, Q4(b)(ii) (2 marks): Calculate the enthalpy change of formation of cyclobutane. (2)
- June 2024, AS Paper 2, Q8(a)(i) (2 marks): Write the equation to represent the enthalpy change of combustion of methanol. Include state symbols. (2)
- June 2024, AS Paper 2, Q8(a)(ii) (4 marks): Calculate the expected final temperature of the water in the student’s experiment, assuming no experimental errors. (4)
- June 2024, AS Paper 2, Q8(a)(iii) (1 mark): Calculate the percentage error in the experimental temperature rise compared to the theoretical temperature rise from your calculation. (1)
- June 2024, AS Paper 2, Q8(b) (2 marks): Instead of waiting in a queue for a balance which recorded the mass of the spirit burner to 2 decimal places, the student used a balance which recorded the mass
- June 2023, Paper 1, Q6(d)(ii) (3 marks): Another weak acid found in cranberries is quinic acid, C6H7(OH)4COOH. It is neutralised by sodium hydroxide solution in a similar way to benzoic acid. A 25.0 cm
- June 2023, Paper 3, Q4(a) (6 marks): Devise an experimental procedure to determine the enthalpy change of solution for hydrated magnesium sulfate. MgSO4·7H2O(s) + aq → MgSO4(aq) Details of the meth
- June 2023, Paper 3, Q4(b) (2 marks): The enthalpy changes of solution for anhydrous and hydrated magnesium sulfate were found by experiment to be MgSO4(s) + aq → MgSO4(aq) ΔrH = –63.2 kJ mol–1 ΔrH
- June 2023, AS Paper 2, Q5(a)(i) (3 marks): Calculate the enthalpy change, in kJ g–1, when 1.00 g of alcohol Q is burned. Include a sign in your final answer. (3)
- June 2023, AS Paper 2, Q5(a)(ii) (2 marks): At the end of the experiment there was a black deposit of carbon on the bottom of the beaker. Explain the effect of formation of the carbon deposit on your answ
- June 2023, AS Paper 2, Q5(b) (2 marks): Give one theoretical and one practical reason why this procedure is insufficient to identify the alcohol. (2) Theoretical reason Practical reason
- June 2023, AS Paper 2, Q7(b) (2 marks): The equation for the complete combustion of butan‑1‑ol is shown. CH3CH2CH2CH2OH(l) + 6O2(g) → 4CO2(g) + 5H2O(l) ΔcH d = –2675.6 kJ mol–1 Draw a labelled enthalp
- June 2023, AS Paper 2, Q8(a) (2 marks): State the two conditions denoted by the standard symbol d for this reaction. (2)
- June 2023, AS Paper 2, Q8(b)(i) (2 marks): Draw a Hess’s Law cycle that would enable you to use the data provided to calculate the enthalpy change of formation of gaseous water, ΔrH. (2) H2(g) + ½O2(g) →
- June 2023, AS Paper 2, Q8(b)(ii) (3 marks): Calculate the enthalpy change for the reaction shown. H2(g) + ½O2(g) → H2O(g) (3)
- June 2022, Paper 1, Q5(a) (1 mark): Magnesium carbonate reacts with dilute hydrochloric acid at room temperature. MgCO3(s) + 2HCl(aq) → MgCl2(aq) + CO2(g) + H2O(l) When the reaction is carried out
- June 2022, Paper 1, Q5(b) (3 marks): State what is meant by the standard enthalpy change of formation of aluminium oxide, Al2O3(s). Include standard conditions. (3)
- June 2022, AS Paper 2, Q3(a)(i) (3 marks): Calculate the enthalpy change of combustion of decane, using the mean bond enthalpy values in the table. (3) Mean bond enthalpy Bond / kJ mol−1 C C 347 C H 413
- June 2022, AS Paper 2, Q3(a)(ii) (2 marks): A data book value for the enthalpy change of combustion of decane is −6 778 kJ mol−1 . Give two reasons for the difference between your answer to (a)(i) and thi
- June 2022, AS Paper 2, Q4(a)(i) (2 marks): Plot the results using the axes provided. Include two straight lines of best fit, extrapolated until they meet. (2) 27 26 25 24 23 22 21 20 0 10 20 30 40 50 60
- June 2022, AS Paper 2, Q4(a)(ii) (1 mark): Determine the maximum temperature rise from your graph. (1)
- June 2022, AS Paper 2, Q4(a)(iv) (3 marks): The reaction that occurs is NH3(aq) + CH3COOH(aq) → NH4 +(aq) + CH3COO−(aq) Calculate the enthalpy change per mole for this reaction. Include a sign and units i
- June 2022, AS Paper 2, Q4(b)(i) (1 mark): The temperature of the reaction mixture initially increased because the reaction is (1) A endothermic so energy is absorbed by the water B endothermic so energy
- June 2022, AS Paper 2, Q4(b)(ii) (1 mark): Give the main reason why, after the end‑point was reached, the temperature of the solution decreased. (1)
- June 2022, AS Paper 2, Q7(b)(i) (2 marks): Complete the Hess cycle to enable you to calculate the enthalpy change of formation, ∆fH298 , of NOCl. Include state symbols. (2) 2NO(g) + Cl2(g) 2NOCl(g)
- June 2022, AS Paper 2, Q7(b)(ii) (2 marks): Calculate the enthalpy change of formation, ∆fH298 , of NOCl given the data 2NO(g) + Cl2(g) 2NOCl(g) ∆rH298 = −75.6 kJ mol−1 enthalpy change of formation of N
- November 2021, Paper 1, Q5(a)(i) (3 marks): Chlorine and phosphorus (P4) can react to form phosphorus(V) chloride. The structure of a molecule of phosphorus is P P P P Some mean bond enthalpy values are s
- November 2021, Paper 1, Q5(a)(ii) (1 mark): Give a reason why bond enthalpy values are always positive. (1)
- November 2021, Paper 3, Q7(a)(i) (1 mark): Complete the table. (1)
- November 2021, Paper 3, Q7(a)(iii) (3 marks): Calculate the enthalpy change for the reaction between sodium hydrogencarbonate and hydrochloric acid, using the results of the experiment. Include a sign and u
- November 2021, Paper 3, Q7(b)(i) (2 marks): Complete the Hess cycle with appropriate formulae and labelled arrows. (2) ∆rH 2NaHCO3(s) Na2CO3(s) + H2O(l) + CO2(g)
- November 2021, Paper 3, Q7(b)(ii) (3 marks): Calculate the enthalpy change for the decomposition of sodium hydrogencarbonate. Include a sign and units in your answer. ∆rH 2NaHCO3(s) Na2CO3(s) + H2O(l) + CO
- November 2021, Paper 3, Q7(c)(i) (1 mark): Calculate the percentage error in this student’s value. (1)
- November 2021, Paper 3, Q7(c)(ii) (1 mark): Calculate the percentage uncertainties in measuring 50 cm3 of hydrochloric acid using a burette and using a measuring cylinder. (1) Apparatus Uncertainty Percen
- November 2021, Paper 3, Q7(c)(iii) (1 mark): Give a reason why using a burette rather than a measuring cylinder will not improve the accuracy of the experiment. (1)
- November 2021, Paper 3, Q7(c)(iv) (5 marks): Describe changes to the method and how the data is used that would improve the accuracy of the determination of the temperature change in Experiment 2. Your des
- November 2021, AS Paper 2, Q2(a)(i) (3 marks): Complete the Hess’s Law cycle to include the enthalpy change of formation of both phosphorus chlorides. Include the labels of the missing enthalpy changes. ΔvH
- November 2021, AS Paper 2, Q2(a)(ii) (2 marks): Calculate the enthalpy change for the thermal decomposition of PCl5(g) to PCl3(g) and Cl2(g), using the data given in the table. Include a sign and units in you
- November 2021, AS Paper 2, Q4(b) (1 mark): Which two terms could be used to describe this reaction? (1) Enthalpy change Type of process A endothermic hydration B exothermic hydration C exothermic dehydra
- November 2021, AS Paper 2, Q4(c)(ii) (4 marks): Calculate the enthalpy change, in kJ mol–1, for this reaction. Include a sign in your answer and give your answer to an appropriate number of significant figure
- November 2021, AS Paper 2, Q4(c)(iii) (2 marks): Deduce which measurement has the greatest uncertainty in this experiment. Justify your answer by calculating the percentage uncertainty of this piece of apparat
- November 2021, AS Paper 2, Q9(a)(i) (3 marks): Calculate the enthalpy change for the forward reaction shown in the equation, selecting from the bond enthalpies in the table. Include a sign in your answer. (3
- November 2021, AS Paper 2, Q9(a)(ii) (2 marks): A data book gives the standard enthalpy change of formation of ammonia as –46.1 kJ mol–1. Give two reasons for the difference between this value and the value t
- October 2020, Paper 1, Q6(a)(i) (2 marks): When researching the bond enthalpy data, the student claimed that it was not necessary to find the value for the C=C bond as they could use the value for a C–C
- October 2020, Paper 1, Q6(a)(ii) (3 marks): Calculate a value for the enthalpy of combustion of prop-2-en-1-ol using the data shown. C3H6O(g) + 4O2(g) → 3CO2(g) + 3H2O(g) C=C C=O O=O Bond C−C C−O O−H C−H
- October 2020, Paper 3, Q4(b) (3 marks): The reaction of hydrated copper(II) sulfate with water is shown. CuSO4.5H2O(s) + aq → CuSO4(aq) ∆H1 = +18.2 kJ mol−1 Calculate the temperature change that would
- October 2020, Paper 3, Q4(c)(i) (3 marks): Draw to scale, on the graph paper, a labelled enthalpy level diagram which shows the enthalpy changes for the reactions of water with hydrated copper(II) sulfat
- October 2020, Paper 3, Q4(c)(ii) (1 mark): Use your enthalpy level diagram in (c)(i) to determine the enthalpy change, ∆rH, for the reaction CuSO4(s) + 5H2O(l) → CuSO4.5H2O(s) You must show your working
- October 2020, Paper 3, Q4(d) (1 mark): State why the enthalpy change for the reaction of one mole of anhydrous copper(II) sulfate with five moles of water to form hydrated copper(II) sulfate, CuSO4.5
- October 2020, AS Paper 1, Q3(c) (2 marks): Hydrazine has been used as a rocket fuel. It is a powerful reducing agent and will react very exothermically with oxidising agents such as hydrogen peroxide. Th
- October 2020, AS Paper 2, Q4(a) (4 marks): Use the data to calculate a value for the enthalpy change of combustion of one mole of methanol. Give your answer to an appropriate number of significant figure
- October 2020, AS Paper 2, Q4(c) (3 marks): Calculate a value for the standard enthalpy change of combustion of gaseous methanol using the enthalpy change for Step 2 and the standard enthalpy change of co
- October 2020, AS Paper 2, Q5(a) (2 marks): Iodine monochloride gas can be produced by the reaction between iodine vapour and chlorine gas. The reaction is exothermic. I2(g) + Cl2(g) → 2ICl(g) ΔrH = −30 k
- June 2019, Paper 1, Q3(a)(i) (1 mark): Which piece of equipment has the smallest measurement uncertainty for the measurement of 50.0 cm3 of sodium hydroxide solution? (1) Equipment Measurement uncert
- June 2019, Paper 1, Q3(a)(ii) (3 marks): 50.0 cm3 of propanoic acid solution, of concentration 1.00 mol dm–3, was added and thoroughly mixed with the sodium hydroxide solution in the polystyrene cup. T
- June 2019, Paper 1, Q3(b)(i) (1 mark): Which graph shows the correct way that the maximum temperature rise should be determined? (1) A B 45 45 40 40 35 35 ¨T 30 30 ¨T 25 25 20 20 15 15 0 0 0 60 120 1
- June 2019, AS Paper 2, Q3(a)(i) (2 marks): State what is meant by the term ‘standard enthalpy change of combustion’. (2)
- June 2019, AS Paper 2, Q3(a)(ii) (2 marks): Write the equation, including state symbols, for the reaction that occurs when the standard enthalpy change of combustion of octane, C8H18(l), is measured. (2)
- June 2019, AS Paper 2, Q3(a)(iii) (2 marks): The standard enthalpy change of combustion of octane is –5 470 kJ mol–1. Complete the reaction profile diagram for the combustion of octane. 9, Include labels s
- June 2019, AS Paper 2, Q3(b) (4 marks): Enthalpy changes of reactions which cannot be measured directly can be calculated using standard enthalpy changes of combustion. The table shows some of these v
- June 2019, AS Paper 2, Q3(c)(i) (1 mark): the mean bond enthalpy of a C−−H bond. (1)
- June 2019, AS Paper 2, Q3(c)(ii) (2 marks): the mean bond enthalpy of a C−−C bond. (2)
- June 2018, Paper 1, Q3(a) (1 mark): Give a reason why excess sodium hydroxide was used. (1)
- June 2018, Paper 1, Q3(b) (4 marks): Calculate the enthalpy change of neutralisation for the reaction between nitric acid and sodium hydroxide solution, using the results of the experiment. Give yo
- June 2018, AS Paper 2, Q3(b)(i) (3 marks): Use this equation, and the enthalpy changes of formation of nitrogen(II) oxide and water, to calculate the enthalpy change of formation of ammonia in kJ mol−1.
- June 2018, AS Paper 2, Q8(c)(i) (4 marks): Using the bond enthalpies shown in the table, calculate a value for the enthalpy change, in kJ mol−1, for the complete combustion of 2-methylpropan-2-ol. (4) Bo
- June 2018, AS Paper 2, Q8(c)(ii) (2 marks): 2-methylpropan-2-ol burns in air with a smoky flame. Explain how burning with a smoky flame affects the value of the experimentally determined enthalpy change o
- June 2018, AS Paper 2, Q8(c)(iii) (1 mark): A Data Book value for the enthalpy change of combustion of 2-methylpropan-2-ol is −2643.8 kJ mol−1. Give the main reason for the difference between this value a
- June 2017, Paper 1, Q5(a) (1 mark): Which is the equation for the standard enthalpy change of formation, ¨fH , of aluminium oxide? (1) A 4Al(s) + 3 O2(g) r 2Al2O3(s) B 4Al(s) + 6 O(g) r 2Al2O3(s)
- June 2017, Paper 1, Q5(b) (3 marks): Propan-1-ol is dehydrated to form propene. H H H H H C C ¨rH = +42 kJ mol−1 + H2O H C C C O H H C H H H H H H The relevant mean bond enthalpies are given in the
- June 2017, Paper 1, Q7(a) (3 marks): The enthalpy change when hydrochloric acid reacts with aqueous ammonia is –53.4 kJ mol–1. HCl(aq) + NH3(aq) r NH4Cl(aq) Calculate the temperature change you wou
- June 2017, Paper 1, Q7(b) (6 marks): The table shows the enthalpy changes of reaction when 1 mol of different acids are neutralised by sodium hydroxide solution, at 298 K. Enthalpy change of reacti
- June 2017, Paper 3, Q4(a) (2 marks): Complete Table 1, giving the values to an appropriate number of decimal places.
- June 2017, Paper 3, Q4(b) (2 marks): Write the equation that represents the reaction that occurs when the standard en
- June 2017, Paper 3, Q4(c) (4 marks): Use Student 1’s result to calculate the enthalpy change of combustion of methano
- June 2017, Paper 3, Q4(d)(i) (1 mark): Student 1 compared the experimental value for the enthalpy change of combustion
- June 2017, Paper 3, Q4(d)(ii) (3 marks): Compare and contrast the use of a 250 cm3 measuring cylinder to measure out the
- June 2017, Paper 3, Q4(d)(iii) (3 marks): Student 1 calculated the uncertainties in the remaining measurements. However,
- June 2017, Paper 3, Q4(e) (2 marks): Student 1 decided to repeat the experiment. Student 1 used the copper calorimete
- June 2017, Paper 3, Q4(f) (2 marks): Student 2 followed the original instructions provided, but extinguished the flam
- June 2017, Paper 3, Q4(g) (2 marks): Another student, Student 3, used the results from Student 1’s first experiment t
- June 2017, AS Paper 2, Q3(b)(i) (3 marks): Use these results to calculate the enthalpy change of combustion of hydrocarbon A in kJ mol–1. Give your answer to an appropriate number of significant figures
- June 2017, AS Paper 2, Q3(b)(ii) (1 mark): The beaker used in this experiment was made of copper rather than glass. Give a reason for this. (1)
- June 2016, AS Paper 2, Q4(b) (2 marks): Write the equation to represent the standard enthalpy change of formation of ethanol. Include state symbols. (2)
- June 2016, AS Paper 2, Q4(c)(i) (3 marks): The table shows some mean bond enthalpy data. Bond C C C H C O O H O O C O Mean bond enthalpy 347 413 358 464 498 805 / kJ mol−1 Calculate the enthalpy change,
- June 2016, AS Paper 2, Q4(c)(ii) (2 marks): Complete the reaction profile diagram for the combustion of ethanol and fully label the diagram. (2) enthalpy C2H5OH(l) + 3O2(g) reaction pathway
- June 2016, AS Paper 2, Q4(c)(iii) (1 mark): A data book value for the standard enthalpy change of combustion of ethanol is −1367.3 kJ mol−1. Give the main reason why the value you calculated in (b)(i) is
- June 2016, AS Paper 2, Q6(a) (4 marks): In the first experiment, the student determines the enthalpy change of solution for anhydrous sodium carbonate. 50.0g of distilled water is placed in a polystyr
- June 2016, AS Paper 2, Q6(b) (2 marks): In the second experiment, the student determines the enthalpy change of solution for hydrated sodium carbonate. Na2CO3.10H2O(s) + aq o Na2CO3(aq) ¨H = + 53.7kJ
- June 2016, AS Paper 2, Q6(c) (2 marks): Hydrated sodium carbonate slowly loses some water of crystallisation when left in air. Explain how the enthalpy change in the second experiment would compare wi
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