A-level
CHEMISTRY ACTUAL 2025 PAPER MERGED
WITH MARK SCHEME
Paper 3
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
, 2
Do not write
outside the
box
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
• a scientific calculator, which you are expected to use where appropriate. Question Mark
1
Instructions
• Use black ink or black ball-point pen. 2
• Fill in the boxes at the top of this page.
• Answer all questions. 3
• You must answer the questions in the spaces provided. Do not write outside the
box around each page or on blank pages. 4
• If you need extra space for your answer(s), use the lined pages at the end of
this book. Write the question number against your answer(s). 5
• All working must be shown.
• Do all rough work in this book. Cross through any work you do not want to 6
be marked.
Section B
Information
• The marks for questions are shown in brackets. TOTAL
• 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* 7405/3
IB/M/Jun25/G4007/V5
Section A
Answer all questions in this section.
IB/M/Jun25/7405/3
, 3
Do not write
outside the
box
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]
Turn over ►
IB/M/Jun25/7405/3
, 4
Do not write
outside the
box
*02*
0 1 .2
A student does an experiment to determine a value for the enthalpy of solution of
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]
IB/M/Jun25/7405/3
CHEMISTRY ACTUAL 2025 PAPER MERGED
WITH MARK SCHEME
Paper 3
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
, 2
Do not write
outside the
box
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
• a scientific calculator, which you are expected to use where appropriate. Question Mark
1
Instructions
• Use black ink or black ball-point pen. 2
• Fill in the boxes at the top of this page.
• Answer all questions. 3
• You must answer the questions in the spaces provided. Do not write outside the
box around each page or on blank pages. 4
• If you need extra space for your answer(s), use the lined pages at the end of
this book. Write the question number against your answer(s). 5
• All working must be shown.
• Do all rough work in this book. Cross through any work you do not want to 6
be marked.
Section B
Information
• The marks for questions are shown in brackets. TOTAL
• 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* 7405/3
IB/M/Jun25/G4007/V5
Section A
Answer all questions in this section.
IB/M/Jun25/7405/3
, 3
Do not write
outside the
box
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]
Turn over ►
IB/M/Jun25/7405/3
, 4
Do not write
outside the
box
*02*
0 1 .2
A student does an experiment to determine a value for the enthalpy of solution of
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]
IB/M/Jun25/7405/3
