Pearson Edexcel International Advanced Level Chemistry UNIT 2 MAY 2025 QUESTION PAPER: Energetics, Group Chemistry, Halogenoalkanes and Alcohols

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Pearson Edexcel International Advanced Level
Monday 12 May 2025
Morning (Time: 1 hour 30 minutes) Paper
reference WCH12/01
Chemistry  


International Advanced Subsidiary/Advanced Level
UNIT 2: Energetics, Group Chemistry, Halogenoalkanes
and Alcohols

You must have: Total Marks
Scientific calculator, Data Booklet



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 80.
The marks for each question are shown in brackets
– use this as a guide as to how much time to spend on each question.
• Instructure
the question marked with an asterisk (*), marks will be awarded for your ability to
your answer logically, showing how the points that you make are related or
follow on from each other where appropriate.
• A Periodic Table is printed on the back cover of this paper.

Advice:
•• Read each question carefully before you start to answer it.
Try to answer every question.
•• Show all your working in calculations and include units where appropriate.
Check your answers if you have time at the end. Turn over


P78743A
©2025 Pearson Education Ltd.
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, SECTION A
Answer ALL the questions in this section.




DO NOT WRITE IN THIS AREA DO NOT WRITE IN THIS AREA DO NOT WRITE IN THIS AREA
You should aim to spend no more than 20 minutes on this section.
For each question, select one answer from A to D and put a cross in the box . If you change
your mind, put a line through the box and then mark your new answer with a cross .

1: 25 cm3 of sodium hydroxide solution, of concentration 2.00 mol dm–3, was added to
30 cm3 of ethanoic acid solution, of concentration 1.00 mol dm–3, in a polystyrene cup.
The mixture was stirred, causing the temperature to increase by 6.5 °C.
(a) What is the expression for the enthalpy change of neutralisation of
sodium hydroxide and ethanoic acid, in J mol–1?
[Assume: the specific heat capacity of the mixture = 4.18 J g–1 °C–1
the density of the mixture = 1.00 g cm–3]
(1)
A –(25 × 4.18 × 6.5) ÷ 0.05
B –(30 × 4.18 × 6.5) ÷ 0.03

C –(55 × 4.18 × 6.5) ÷ 0.05

D –(55 × 4.18 × 6.5) ÷ 0.03


(b) The measurement uncertainty in the thermometer used in the experiment is
±0.5 °C for each reading.
What is the percentage uncertainty in the temperature change of 6.5 °C?
(1)
A 3.8%

B 7.7%

C 15.4%

D 30.8%
(Total for Question 1 = 2 marks)
Use this space for any rough working. Anything you write in this space will gain no credit.




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, 2: (a) Methane burns to produce carbon dioxide and water vapour.

CH4(g) + 2O2(g) → CO2(g) + 2H2O(g) ΔH = –810 kJ mol–1
DO NOT WRITE IN THIS AREA DO NOT WRITE IN THIS AREA DO NOT WRITE IN THIS AREA




Some bond enthalpy data are shown.


Bond Bond enthalpy / kJ mol–1

C H 413

O O 498

O H 464


What is the mean bond enthalpy for the C O bond, in kJ mol–1?
(1)
A 552
B 801

C 1016

D 1265

(b) A data book value for the standard enthalpy change of combustion of methane
is –890 kJ mol–1.
What is the experimental value for the enthalpy change of vaporisation of water
in kJ mol–1?

H2O(l) → H2O(g)
(1)
A –40

B +40

C –80

D +80
(Total for Question 2 = 2 marks)

3: Which amine, with molecular formula C3H9N , has the lowest boiling temperature?

A (CH3)3N

B CH3CH2NHCH3

C CH3CH2CH2NH2

D CH3CH(NH2)CH3
(Total for Question 3 = 1 mark)

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 *P78743A0324* Turn over