Please check the examination details below before entering your candidate information
Candidate surname Other names
Centre Number Candidate Number
Pearson Edexcel International Advanced Level
Friday 23 May 2025
Morning (Time: 1 hour 20 minutes) Paper
reference WCH13/01
Chemistry
International Advanced Subsidiary/Advanced Level
UNIT 3: Practical Skills in Chemistry I
You must have: Total Marks
Scientific calculator
Instructions
•• Use black ink or ball-point pen.
If pencil is used for diagrams/sketches/graphs it must be dark (HB or B).
• Fill in the boxes at the top of this page with your name,
centre number and candidate number.
•• Answer all questions.
Answer the questions in the spaces provided
– there may be more space than you need.
Information
•• The total mark for this paper is 50.
The marks for each question are shown in brackets
– use this as a guide as to how much time to spend on each question.
• You will be assessed on your ability to organise and present information, ideas,
descriptions and arguments clearly and logically, including your use of grammar,
punctuation and spelling.
• A Periodic Table is printed on the back cover of this paper.
Advice
•• Read each question carefully before you start to answer it.
Show all your working in calculations and include units where appropriate.
•• Try to answer every question.
Check your answers if you have time at the end.
Turn over
P78744A
©2025 Pearson Education Ltd.
Y:1/1/1/1/
*P78744A0116*
, Answer ALL the questions. Write your answers in the spaces provided.
1 Two isomeric organic liquids, P and Q, with one functional group, contain only
DO NOT WRITE IN THIS AREA DO NOT WRITE IN THIS AREA DO NOT WRITE IN THIS AREA
carbon, hydrogen and oxygen. They have the same functional group.
(a) Phosphorus(V) chloride is added to separate samples of P and Q.
A gas, R, is evolved in each reaction.
Identify R, by name or formula.
(1)
. . . . . . . . . . . .. .. .. .. .. .. .. .. .. .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ............................................................................................................................................ ................ . . . . . . . . . . . . . . . . . . . .
(b) When a few drops of acidified potassium dichromate(VI) are added to separate
samples of P and Q and the mixtures gently heated, a reaction occurs.
(i) Give the colour change of the mixtures during heating.
(1)
From . . .. .. .. .. .. .. .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ............................................................................................................................................................ . . . . . . . . . . . . . . . . . . . .
To .. . . . .. .. .. .. .. .. .. .. .. .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ........................................................................................................................................... ................ . . . . . . . . . . . . . . . . . . . .
(ii) Identify the functional group present in P and Q.
(1)
. . . . . . . . . . . .. .. .. .. .. .. .. .. .. .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ............................................................................................................................................ ................ . . . . . . . . . . . . . . . . . . . .
(c) Mass spectra of P and Q show a molecular ion peak at m / z = 60.
The mass spectrum of P has its most intense peak at m / z = 31 and this peak is
not present in the mass spectrum of Q.
The spectrum of Q has its most intense peak at m / z = 45 which is less intense in
the mass spectrum of P.
In the alternative isomer these peaks are very small.
For each of these peaks, give the formula of one ion that could be responsible for
its formation.
(3)
60 . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
45 . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
31 . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2
*P78744A0216*
, (d) Deduce the structural formulae of P and Q.
(2)
DO NOT WRITE IN THIS AREA DO NOT WRITE IN THIS AREA DO NOT WRITE IN THIS AREA
P
Q
(Total for Question 1 = 8 marks)
3
*P78744A0316* Turn over
Candidate surname Other names
Centre Number Candidate Number
Pearson Edexcel International Advanced Level
Friday 23 May 2025
Morning (Time: 1 hour 20 minutes) Paper
reference WCH13/01
Chemistry
International Advanced Subsidiary/Advanced Level
UNIT 3: Practical Skills in Chemistry I
You must have: Total Marks
Scientific calculator
Instructions
•• Use black ink or ball-point pen.
If pencil is used for diagrams/sketches/graphs it must be dark (HB or B).
• Fill in the boxes at the top of this page with your name,
centre number and candidate number.
•• Answer all questions.
Answer the questions in the spaces provided
– there may be more space than you need.
Information
•• The total mark for this paper is 50.
The marks for each question are shown in brackets
– use this as a guide as to how much time to spend on each question.
• You will be assessed on your ability to organise and present information, ideas,
descriptions and arguments clearly and logically, including your use of grammar,
punctuation and spelling.
• A Periodic Table is printed on the back cover of this paper.
Advice
•• Read each question carefully before you start to answer it.
Show all your working in calculations and include units where appropriate.
•• Try to answer every question.
Check your answers if you have time at the end.
Turn over
P78744A
©2025 Pearson Education Ltd.
Y:1/1/1/1/
*P78744A0116*
, Answer ALL the questions. Write your answers in the spaces provided.
1 Two isomeric organic liquids, P and Q, with one functional group, contain only
DO NOT WRITE IN THIS AREA DO NOT WRITE IN THIS AREA DO NOT WRITE IN THIS AREA
carbon, hydrogen and oxygen. They have the same functional group.
(a) Phosphorus(V) chloride is added to separate samples of P and Q.
A gas, R, is evolved in each reaction.
Identify R, by name or formula.
(1)
. . . . . . . . . . . .. .. .. .. .. .. .. .. .. .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ............................................................................................................................................ ................ . . . . . . . . . . . . . . . . . . . .
(b) When a few drops of acidified potassium dichromate(VI) are added to separate
samples of P and Q and the mixtures gently heated, a reaction occurs.
(i) Give the colour change of the mixtures during heating.
(1)
From . . .. .. .. .. .. .. .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ............................................................................................................................................................ . . . . . . . . . . . . . . . . . . . .
To .. . . . .. .. .. .. .. .. .. .. .. .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ........................................................................................................................................... ................ . . . . . . . . . . . . . . . . . . . .
(ii) Identify the functional group present in P and Q.
(1)
. . . . . . . . . . . .. .. .. .. .. .. .. .. .. .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ............................................................................................................................................ ................ . . . . . . . . . . . . . . . . . . . .
(c) Mass spectra of P and Q show a molecular ion peak at m / z = 60.
The mass spectrum of P has its most intense peak at m / z = 31 and this peak is
not present in the mass spectrum of Q.
The spectrum of Q has its most intense peak at m / z = 45 which is less intense in
the mass spectrum of P.
In the alternative isomer these peaks are very small.
For each of these peaks, give the formula of one ion that could be responsible for
its formation.
(3)
60 . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
45 . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
31 . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2
*P78744A0216*
, (d) Deduce the structural formulae of P and Q.
(2)
DO NOT WRITE IN THIS AREA DO NOT WRITE IN THIS AREA DO NOT WRITE IN THIS AREA
P
Q
(Total for Question 1 = 8 marks)
3
*P78744A0316* Turn over
