Please write clearly in block capitals.
Centre number Candidate number
Surname
Forename(s)
Candidate signature
I declare this is my own work.
A-level
CHEMISTRY
Paper 3
Friday 20 June 2025 Morning Time allowed: 2 hours
Materials
For this paper you must have: For Examiner’s Use
• the Periodic Table/Data Booklet, provided as an insert (enclosed)
• a ruler with millimetre measurements Question Mark
• a scientific calculator, which you are expected to use where appropriate. 1
2
Instructions
• Use black ink or black ball-point pen. 3
• Fill in the boxes at the top of this page. 4
• Answer all questions. 5
• You must answer the questions in the spaces provided. Do not write outside
6
the box around each page or on blank pages.
• If you need extra space for your answer(s), use the lined pages at the end of Section B
this book. Write the question number against your answer(s).
TOTAL
• All working must be shown.
• Do all rough work in this book. Cross through any work you do not
want to be marked.
Information
• The marks for questions are shown in brackets.
• The maximum mark for this paper is 90.
Advice
• You are advised to spend 70 minutes on Section A and 50 minutes on Section B.
*Jun257405301*
IB/M/Jun25/G4007/V5 7405/3
, 2
Do not write
outside the
Section A box
Answer all questions in this section.
0 1 A value for enthalpy of solution can be determined from the results of a calorimetry
experiment or by the application of Hess’s law.
0 1 . 1 Give the equation, including state symbols, for the process that occurs when the
enthalpy of solution of potassium hydroxide is determined.
[1 mark]
*02*
IB/M/Jun25/7405/3
, 3
Do not write
outside the
0 1 . 2 A student does an experiment to determine a value for the enthalpy of solution of box
potassium hydroxide.
The student uses this method.
• Add some distilled water to a measuring cylinder and record the volume.
• Pour the water into a polystyrene cup.
• Record the temperature of the water in the cup.
• Add 3.00 g of solid KOH to the water in the cup.
• Stir the solution and record the maximum temperature reached.
Table 1 shows the student’s results.
Table 1
Initial temperature / °C 18.1
Final temperature / °C 30.4
The student calculated the enthalpy of solution of potassium hydroxide
to be –51.3 kJ mol–1
The specific heat capacity of the solution, c = 4.18 J K–1 g–1
Assume the density of the solution = 1.00 g cm–3
Calculate the volume of water that the student added to the cup.
[5 marks]
Volume of water Units
Turn over ►
*03*
IB/M/Jun25/7405/3
, 4
Do not write
outside the
0 1 . 3 Table 2 shows some enthalpy change data. box
Table 2
Enthalpy change / kJ mol–1
Enthalpy of lattice formation of
–789
potassium hydroxide
Enthalpy of hydration of potassium ions –322
Enthalpy of hydration of hydroxide ions –528
Use the data in Table 2 to calculate the enthalpy of solution for potassium hydroxide.
[2 marks]
Enthalpy of solution kJ mol–1
0 1 . 4 Suggest why the value calculated in Question 01.3 is different from the
experimental value given in Question 01.2.
[1 mark]
9
*04*
IB/M/Jun25/7405/3
Centre number Candidate number
Surname
Forename(s)
Candidate signature
I declare this is my own work.
A-level
CHEMISTRY
Paper 3
Friday 20 June 2025 Morning Time allowed: 2 hours
Materials
For this paper you must have: For Examiner’s Use
• the Periodic Table/Data Booklet, provided as an insert (enclosed)
• a ruler with millimetre measurements Question Mark
• a scientific calculator, which you are expected to use where appropriate. 1
2
Instructions
• Use black ink or black ball-point pen. 3
• Fill in the boxes at the top of this page. 4
• Answer all questions. 5
• You must answer the questions in the spaces provided. Do not write outside
6
the box around each page or on blank pages.
• If you need extra space for your answer(s), use the lined pages at the end of Section B
this book. Write the question number against your answer(s).
TOTAL
• All working must be shown.
• Do all rough work in this book. Cross through any work you do not
want to be marked.
Information
• The marks for questions are shown in brackets.
• The maximum mark for this paper is 90.
Advice
• You are advised to spend 70 minutes on Section A and 50 minutes on Section B.
*Jun257405301*
IB/M/Jun25/G4007/V5 7405/3
, 2
Do not write
outside the
Section A box
Answer all questions in this section.
0 1 A value for enthalpy of solution can be determined from the results of a calorimetry
experiment or by the application of Hess’s law.
0 1 . 1 Give the equation, including state symbols, for the process that occurs when the
enthalpy of solution of potassium hydroxide is determined.
[1 mark]
*02*
IB/M/Jun25/7405/3
, 3
Do not write
outside the
0 1 . 2 A student does an experiment to determine a value for the enthalpy of solution of box
potassium hydroxide.
The student uses this method.
• Add some distilled water to a measuring cylinder and record the volume.
• Pour the water into a polystyrene cup.
• Record the temperature of the water in the cup.
• Add 3.00 g of solid KOH to the water in the cup.
• Stir the solution and record the maximum temperature reached.
Table 1 shows the student’s results.
Table 1
Initial temperature / °C 18.1
Final temperature / °C 30.4
The student calculated the enthalpy of solution of potassium hydroxide
to be –51.3 kJ mol–1
The specific heat capacity of the solution, c = 4.18 J K–1 g–1
Assume the density of the solution = 1.00 g cm–3
Calculate the volume of water that the student added to the cup.
[5 marks]
Volume of water Units
Turn over ►
*03*
IB/M/Jun25/7405/3
, 4
Do not write
outside the
0 1 . 3 Table 2 shows some enthalpy change data. box
Table 2
Enthalpy change / kJ mol–1
Enthalpy of lattice formation of
–789
potassium hydroxide
Enthalpy of hydration of potassium ions –322
Enthalpy of hydration of hydroxide ions –528
Use the data in Table 2 to calculate the enthalpy of solution for potassium hydroxide.
[2 marks]
Enthalpy of solution kJ mol–1
0 1 . 4 Suggest why the value calculated in Question 01.3 is different from the
experimental value given in Question 01.2.
[1 mark]
9
*04*
IB/M/Jun25/7405/3
