worked solutions
model answers
, Oxford Cambridge and RSA
Monday 19 May 2025 – Morning
GCSE (9–1) Chemistry A (Gateway Science)
J248/03 (Higher Tier)
Time allowed: 1 hour 45 minutes
H
You must have:
• a ruler (cm/mm)
*1859 7188 55*
• the Data Sheet for GCSE (9–1) Chemistry A
(inside this document)
You can use:
• a scientific or graphical calculator
• an HB pencil
* J 2 4 8 0 3 *
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 pages 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 90.
• 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 [601/8663/X] OCR is an exempt Charity
DC (DE/SW) 353817/6 Turn over
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, 2
Section A
You should spend a maximum of 30 minutes on this section.
Write your answer to each question in the box provided.
1 How many covalent bonds can a carbon atom form?
A 2
B 4
C 6
D 8
Your answer [1]
2 What is the ionic equation for neutralisation?
A H– + OH+ H2O
B H+ + OH– H2O
C 2H2 + 2O2– 2H2O
D H+ + O2 HO2
Your answer [1]
© OCR 2025
for more: tyrionpapers.com
tyrionpapers.com
, 3
3 Which atomic model was developed by Thomson?
A
+ –
+ – ++
B – + –
+– –
+
C
D
Your answer [1]
4 The diagram shows calcium carbonate, CaCO3, reacting with an acid.
The equation for the reaction is:
CaCO3(s) + 2HCl(aq) CaCl2(aq) + H2O(l) + CO2(g)
What happens to the mass displayed on the balance as the reaction progresses?
A Decreases
B Decreases then increases
C Increases
D Stays the same
Your answer [1]
© OCR 2025 Turn over
for more: tyrionpapers.com
tyrionpapers.com
model answers
, Oxford Cambridge and RSA
Monday 19 May 2025 – Morning
GCSE (9–1) Chemistry A (Gateway Science)
J248/03 (Higher Tier)
Time allowed: 1 hour 45 minutes
H
You must have:
• a ruler (cm/mm)
*1859 7188 55*
• the Data Sheet for GCSE (9–1) Chemistry A
(inside this document)
You can use:
• a scientific or graphical calculator
• an HB pencil
* J 2 4 8 0 3 *
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 pages 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 90.
• 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 [601/8663/X] OCR is an exempt Charity
DC (DE/SW) 353817/6 Turn over
for more: tyrionpapers.com
tyrionpapers.com
, 2
Section A
You should spend a maximum of 30 minutes on this section.
Write your answer to each question in the box provided.
1 How many covalent bonds can a carbon atom form?
A 2
B 4
C 6
D 8
Your answer [1]
2 What is the ionic equation for neutralisation?
A H– + OH+ H2O
B H+ + OH– H2O
C 2H2 + 2O2– 2H2O
D H+ + O2 HO2
Your answer [1]
© OCR 2025
for more: tyrionpapers.com
tyrionpapers.com
, 3
3 Which atomic model was developed by Thomson?
A
+ –
+ – ++
B – + –
+– –
+
C
D
Your answer [1]
4 The diagram shows calcium carbonate, CaCO3, reacting with an acid.
The equation for the reaction is:
CaCO3(s) + 2HCl(aq) CaCl2(aq) + H2O(l) + CO2(g)
What happens to the mass displayed on the balance as the reaction progresses?
A Decreases
B Decreases then increases
C Increases
D Stays the same
Your answer [1]
© OCR 2025 Turn over
for more: tyrionpapers.com
tyrionpapers.com
