GCSE CHEMISTRY A (GATEWAY SCIENCE) — Actual May 2025 PAST PAPER: Chemistry A
(Higher Tier). All Assessment Questions & Mark Scheme [OCR J248/03]
Exam Resource Summary
The GCSE (9–1) Chemistry A (Gateway Science) May 2025 Higher Tier Paper (OCR J248/03) merges
the full official examination paper with its detailed mark scheme to create a comprehensive revision and
practice resource. This paper assesses students’ understanding of a wide range of chemical concepts,
including atomic structure, bonding, chemical reactions, energetics, kinetics, the periodic table, organic
chemistry, and practical investigation skills. Candidates are expected to apply knowledge to unfamiliar
and theoretical scenarios, interpret and analyse data, and construct clear, well-reasoned scientific
explanations. By presenting each question alongside its marking criteria, this merged resource clarifies
examiner expectations, highlights the analytical and evaluative skills required for top marks, and guides
learners in producing structured, accurate, and complete responses. This integrated format supports
focused revision, strengthens exam technique, and prepares students thoroughly for the 2026 OCR GCSE
Chemistry A (Gateway Science) Higher Tier examination.
OCR is an exempt Charity
Turn over
, 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
, 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
, 4
5 Which ion do solutions of all alkalis contain?
A K+
B H+
C OH–
D SO42–
Your answer [1]
6 What is the relative formula mass of butanoic acid, C3H7COOH?
Relative atomic mass (Ar): C = 12.0 H = 1.0 O = 16.0
A 29.0
B 44.0
C 88.0
D 120.0
Your answer [1]
7 What type of bonding is found in all polymers?
A Covalent
B Electrostatic
C Ionic
D Metallic
Your answer [1]
© OCR 2025
(Higher Tier). All Assessment Questions & Mark Scheme [OCR J248/03]
Exam Resource Summary
The GCSE (9–1) Chemistry A (Gateway Science) May 2025 Higher Tier Paper (OCR J248/03) merges
the full official examination paper with its detailed mark scheme to create a comprehensive revision and
practice resource. This paper assesses students’ understanding of a wide range of chemical concepts,
including atomic structure, bonding, chemical reactions, energetics, kinetics, the periodic table, organic
chemistry, and practical investigation skills. Candidates are expected to apply knowledge to unfamiliar
and theoretical scenarios, interpret and analyse data, and construct clear, well-reasoned scientific
explanations. By presenting each question alongside its marking criteria, this merged resource clarifies
examiner expectations, highlights the analytical and evaluative skills required for top marks, and guides
learners in producing structured, accurate, and complete responses. This integrated format supports
focused revision, strengthens exam technique, and prepares students thoroughly for the 2026 OCR GCSE
Chemistry A (Gateway Science) Higher Tier examination.
OCR is an exempt Charity
Turn over
, 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
, 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
, 4
5 Which ion do solutions of all alkalis contain?
A K+
B H+
C OH–
D SO42–
Your answer [1]
6 What is the relative formula mass of butanoic acid, C3H7COOH?
Relative atomic mass (Ar): C = 12.0 H = 1.0 O = 16.0
A 29.0
B 44.0
C 88.0
D 120.0
Your answer [1]
7 What type of bonding is found in all polymers?
A Covalent
B Electrostatic
C Ionic
D Metallic
Your answer [1]
© OCR 2025
