About this practice. Revision Robin is built and maintained by Bloor Engineering Ltd, a UK-registered company. Our A-Level Chemistry (OCR) questions are written and reviewed in-house to match the current syllabus, each with a plain-English worked explanation. They are original practice material, not the official exam questions and not affiliated with or endorsed by OCR. Always confirm current test rules, fees and content with the official provider. See our Terms and Privacy.
Sit a full mock under the clock at least once. Nerves are half the battle.
Free practice questions
Try 3 real A-Level Chemistry (OCR) questions
Have a go, then reveal the worked explanation. A taster from a bank of 217 original questions. Unlock for unlimited drills and full timed mocks.
Q1. Which type of bonding is present in solid magnesium oxide, MgO?
A. Simple molecular
B. Giant ionic
C. Giant covalent
D. Metallic
Show answer & explanation
✓ Answer: B. Giant ionic
MgO is formed by complete transfer of electrons from Mg to O, giving Mg2+ and O2- ions held together in a giant lattice by strong electrostatic attraction. This ionic bonding explains its very high melting point, unlike simple molecular substances such as CO2.
Q2. A student burns 0.65 g of ethanol (Mr = 46) under a copper calorimeter containing 100 g of water, raising the temperature by 22.0 °C. Using q = mcΔT with c = 4.18 J g⁻¹ K⁻¹, what is the experimental molar enthalpy of combustion?
A. −9.2 kJ mol⁻¹
B. −651 kJ mol⁻¹
C. −92 kJ mol⁻¹
D. −1367 kJ mol⁻¹
Show answer & explanation
✓ Answer: B. −651 kJ mol⁻¹
q = 100 × 4.18 × 22.0 = 9196 J = 9.196 kJ. Moles of ethanol = 0.65/46 = 0.01413 mol, so molar enthalpy = −9.196/0.01413 ≈ −651 kJ mol⁻¹. This is far less exothermic than the literature value (−1367 kJ mol⁻¹) because of heat loss to the surroundings in a simple calorimeter, a common source of experimental error.
Q3. How does increasing the concentration of the aqueous ions in a half-cell (away from standard 1 mol dm-3) generally affect the electrode potential, according to Le Chatelier-type reasoning used at A-level?
A. It has no effect on the electrode potential
B. Increasing the concentration of the oxidised species makes the electrode potential more negative
C. It always makes the electrode potential exactly zero
D. Increasing the concentration of the oxidised species (e.g. Mn+) makes the electrode potential more positive
Show answer & explanation
✓ Answer: D. Increasing the concentration of the oxidised species (e.g. Mn+) makes the electrode potential more positive
Increasing the concentration of the oxidised species shifts the equilibrium M^n+ + ne- ⇌ M further towards reduction, making the electrode more willing to be reduced, so its electrode potential becomes more positive than the standard value. Conversely, increasing the concentration of the reduced species makes the potential more negative.
Exam mode
Full mock exam
40 random questions, real timing, marked against the official pass mark. Different every time.
The first 8 of 40 questions are free, with your score on them. Finishing the paper, your result against the pass mark and every answer explained come with the paid version.
Try it free
Topic drills
Ten quick questions on one topic, marked instantly with explanations.
1 free drill left.
Who has to sit the A-Level Chemistry (OCR)
Who needs a A-Level Chemistry (OCR)?
Students aged 16-18 for university entry; required/preferred for Medicine, Chemical Engineering, Natural Sciences, Dentistry.
The real A-Level Chemistry (OCR): format
How many questions are in the A-Level Chemistry (OCR)?
The real A-Level Chemistry (OCR) has 3 questions and lasts 360 minutes. Our mock uses 40 questions in 60 minutes.
What it costs, and what a resit costs
How much does the A-Level Chemistry (OCR) cost?
Real exam fee: £340-£565 (written papers only); £650-£1500 (with practical endorsement) for private candidates. Resit fee: £340-£565 (written papers only); additional for practical endorsement if required. Rebooking after a fail: Approx.
Missing key details, state symbols, or not fully answering the question.
Incorrect significant figures and sign errors in calculations.
Figures for the real exam from vertexaisearch.cloud.google.com, checked October 2026. Fees and rules change, so confirm with the test provider before you book.
A-Level Chemistry (OCR): common questions
Frequently asked
What is the pass mark for the A-Level Chemistry (OCR)?
You need 24 out of 40 correct to pass, which is about 60%. Our mocks mark you against this exact threshold.
How long do you get?
The test is timed at 60 minutes. Our full mock runs on the same clock so you can practise your pacing.
Are these the real exam questions?
No. Our questions are original and written to match the current syllabus, so they give realistic practice without copying the official paper. Every answer comes with a plain-English explanation. Always confirm current rules and content with OCR.