worked solutions
model answers
, Oxford Cambridge and RSA
Tuesday 10 June 2025 – Morning
A Level Chemistry A
H432/01 Periodic table, elements and physical chemistry
Time allowed: 2 hours 15 minutes
You must have:
*1849435170*
• the Data Sheet for Chemistry A
You can use:
• a scientific or graphical calculator
• an HB pencil
Please write clearly in black ink. Do not write in the barcodes.
Centre number Candidate number
First name(s)
Last name
INSTRUCTIONS
• Use black ink. You can use an HB pencil, but only for graphs and diagrams.
• Write your answer to each question in the space provided. If you need extra space use
the lined page at the end of this booklet. The question numbers must be clearly shown.
• Answer all the questions.
• Where appropriate, your answer should be supported with working. Marks might be
given for using a correct method, even if your answer is wrong.
INFORMATION
• The total mark for this paper is 100.
• The marks for each question are shown in brackets [ ].
• Quality of extended response will be assessed in questions marked with an asterisk (*).
• This document has 32 pages.
ADVICE
• Read each question carefully before you start your answer
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DC (PQ/SG) 347716/3 Turn over
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, 2
Section A
You should spend a maximum of 20 minutes on this section.
Write your answer to each question in the box provided.
1 The table shows the number of protons and neutrons in four different atoms.
Atom Number of protons Number of neutrons
W 17 18
X 18 18
Y 19 18
Z 18 19
Which two atoms are isotopes of the same element?
A W and X
B X and Y
C X and Z
D Y and Z
Your answer [1]
2 11.895 g of hydrated cobalt(II) chloride, CoCl 2•xH2O, is heated to remove the water of
crystallisation.
After heating to constant mass, the mass of the anhydrous salt was 6.495 g.
What is the value of x?
A 3
B 5
C 6
D 7
Your answer [1]
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, 3
3 The diagram shows the Born-Haber cycle for sodium oxide, Na2O.
2Na+(g) + O2–(g)
2Na+(g) + O(g) + 2e–
2Na(g) + O(g)
2Na(g) + ½O2(g)
2Na(s) + ½O2(g)
Na2O(s)
Why is the value for the second electron affinity of oxygen positive?
A An electron is added to a high energy orbital.
B An electron is added to a negative ion.
C An electron is removed from a gaseous atom.
D An electron is removed from a positive ion.
Your answer [1]
4 What volume, in cm3, of 0.250 mol dm–3 barium hydroxide solution is required to exactly
neutralise 25.0 cm3 of 0.115 mol dm–3 hydrochloric acid?
Ba(OH)2(aq) + 2HCl (aq) BaCl 2(aq) + 2H2O(l)
A 5.75
B 11.50
C 23.00
D 54.35
Your answer [1]
© OCR 2025 Turn over
tyrionpapers.com
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model answers
, Oxford Cambridge and RSA
Tuesday 10 June 2025 – Morning
A Level Chemistry A
H432/01 Periodic table, elements and physical chemistry
Time allowed: 2 hours 15 minutes
You must have:
*1849435170*
• the Data Sheet for Chemistry A
You can use:
• a scientific or graphical calculator
• an HB pencil
Please write clearly in black ink. Do not write in the barcodes.
Centre number Candidate number
First name(s)
Last name
INSTRUCTIONS
• Use black ink. You can use an HB pencil, but only for graphs and diagrams.
• Write your answer to each question in the space provided. If you need extra space use
the lined page at the end of this booklet. The question numbers must be clearly shown.
• Answer all the questions.
• Where appropriate, your answer should be supported with working. Marks might be
given for using a correct method, even if your answer is wrong.
INFORMATION
• The total mark for this paper is 100.
• The marks for each question are shown in brackets [ ].
• Quality of extended response will be assessed in questions marked with an asterisk (*).
• This document has 32 pages.
ADVICE
• Read each question carefully before you start your answer
© OCR 2025 [601/5255/2] OCR is an exempt Charity
DC (PQ/SG) 347716/3 Turn over
tyrionpapers.com
for more: tyrionpapers.com
, 2
Section A
You should spend a maximum of 20 minutes on this section.
Write your answer to each question in the box provided.
1 The table shows the number of protons and neutrons in four different atoms.
Atom Number of protons Number of neutrons
W 17 18
X 18 18
Y 19 18
Z 18 19
Which two atoms are isotopes of the same element?
A W and X
B X and Y
C X and Z
D Y and Z
Your answer [1]
2 11.895 g of hydrated cobalt(II) chloride, CoCl 2•xH2O, is heated to remove the water of
crystallisation.
After heating to constant mass, the mass of the anhydrous salt was 6.495 g.
What is the value of x?
A 3
B 5
C 6
D 7
Your answer [1]
© OCR 2025
tyrionpapers.com
for more: tyrionpapers.com
, 3
3 The diagram shows the Born-Haber cycle for sodium oxide, Na2O.
2Na+(g) + O2–(g)
2Na+(g) + O(g) + 2e–
2Na(g) + O(g)
2Na(g) + ½O2(g)
2Na(s) + ½O2(g)
Na2O(s)
Why is the value for the second electron affinity of oxygen positive?
A An electron is added to a high energy orbital.
B An electron is added to a negative ion.
C An electron is removed from a gaseous atom.
D An electron is removed from a positive ion.
Your answer [1]
4 What volume, in cm3, of 0.250 mol dm–3 barium hydroxide solution is required to exactly
neutralise 25.0 cm3 of 0.115 mol dm–3 hydrochloric acid?
Ba(OH)2(aq) + 2HCl (aq) BaCl 2(aq) + 2H2O(l)
A 5.75
B 11.50
C 23.00
D 54.35
Your answer [1]
© OCR 2025 Turn over
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for more: tyrionpapers.com
