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AS Level Chemistry past papers and topical MCQs with answers

Practise AS Level Chemistry (9701) with 1143 exam-style MCQs by chapter, each with the answer and a short explanation. Every test is marked the moment you finish and shows your score chapter by chapter, so you know what to revise next. It is free and needs no sign-up.

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AS Level Chemistry past papers and topical MCQs with answers

By Team Megalecture · Updated 9 Nov 2026

Practise AS Level Chemistry (9701) with 1143 exam-style MCQs by chapter, each with the answer and a short explanation. Every test is marked the moment you finish and shows your score chapter by chapter, so you know what to revise next. It is free and needs no sign-up.

All AS Level Chemistry notes as one printable pack, PKR 499

1143 questions · 22 chapters · 28 Cambridge past papers · 5 mock exams

What each chapter covers 22 chapters

The questions follow the syllabus chapter by chapter. You can test the whole subject or one chapter at a time.

  1. Atomic structure 94 questionsParticles in the atom and atomic radius, Isotopes, Electrons, energy levels and atomic orbitals, Ionisation energy
  2. Atoms, molecules and stoichiometry 88 questionsRelative masses of atoms and molecules, The mole and the Avogadro constant, Formulas, Reacting masses and volumes (of solutions and gases)
  3. Chemical bonding 154 questionsElectronegativity and bonding, Ionic bonding, Metallic bonding, Covalent bonding and coordinate (dative covalent) bonding, Shapes of molecules, Intermolecular forces, electronegativity and bond properties, Dot-and-cross diagrams
  4. States of matter 44 questionsThe gaseous state: ideal and real gases and pV = nRT, Bonding and structure
  5. Chemical energetics 46 questionsEnthalpy change, ΔH, Hess’s law
  6. Electrochemistry 22 questionsRedox processes: electron transfer and changes in oxidation number (oxidation state)
  7. Equilibria 48 questionsChemical equilibria: reversible reactions, dynamic equilibrium, Brønsted–Lowry theory of acids and bases
  8. Reaction kinetics 63 questionsRate of reaction, Effect of temperature on reaction rates and the concept of activation energy, Homogeneous and heterogeneous catalysts
  9. The Periodic Table: chemical periodicity 68 questionsPeriodicity of physical properties of the elements in Period 3, Periodicity of chemical properties of the elements in Period 3, Chemical periodicity of other elements
  10. Group 2 22 questionsSimilarities and trends in the properties of the Group 2 metals, magnesium to barium
  11. Group 17 88 questionsPhysical properties of the Group 17 elements, The chemical properties of the halogen elements and the hydrogen halides, Some reactions of the halide ions, The reactions of chlorine
  12. Nitrogen and sulfur 22 questions
  13. An introduction to AS Level organic chemistry 92 questionsFormulas, functional groups and the naming of organic compounds, Characteristic organic reactions, Shapes of organic molecules; σ and π bonds, Isomerism: structural isomerism and stereoisomerism
  14. Hydrocarbons 44 questionsAlkanes, Alkenes
  15. Halogen compounds 24 questionsHalogenoalkanes
  16. Hydroxy compounds 22 questionsAlcohols
  17. Carbonyl compounds 24 questionsAldehydes and ketones
  18. Carboxylic acids and derivatives 44 questionsCarboxylic acids, Esters
  19. Nitrogen compounds 44 questionsPrimary amines, Nitriles and hydroxynitriles
  20. Polymerisation 22 questionsAddition polymerisation
  21. Organic synthesis 22 questions
  22. Analytical techniques 46 questionsInfrared spectroscopy, Mass spectrometry
Sample AS Level Chemistry MCQs with answers 12 questions

12 questions from the test, one or two from each chapter. Try each one, then open the answer.

1. Which equation represents the third ionisation energy of aluminium?

  1. A
    Al2+(g) → Al3+(g) + e−
  2. B
    Al(g) → Al3+(g) + 3e−
  3. C
    Al3+(g) → Al4+(g) + e−
  4. D
    Al2+(aq) → Al3+(aq) + e−
Show answer

Answer: A. The third ionisation energy removes one electron from each gaseous 2+ ion. Al(g) → Al3+(g) + 3e− is the sum of the first three; Al3+ → Al4+ is the fourth.

2. What is the mass of one atom of carbon-12? (L = 6.02 × 1023 mol−1)

  1. A
    1.99 × 10−23 g
  2. B
    1.66 × 10−24 g
  3. C
    7.22 × 1024 g
  4. D
    12.0 g
Show answer

Answer: A. One mole of carbon-12 (12.0 g) contains 6.02 × 1023 atoms, so one atom has a mass of 12.0 ÷ (6.02 × 1023) = 1.99 × 10−23 g. 1.66 × 10−24 g is the mass of 1 u.

3. Electronegativities: H 2.2, C 2.6, N 3.0, O 3.4, Cl 3.2. Which bond is the most polar?

  1. A
    C–Cl
  2. B
    N–H
  3. C
    C–O
  4. D
    O–H
Show answer

Answer: D. Polarity increases with the electronegativity difference: O–H 1.2, N–H 0.8, C–O 0.8, C–Cl 0.6.

4. 2.50 g of calcium carbonate is heated until it is completely decomposed: CaCO3(s) → CaO(s) + CO2(g). What volume of carbon dioxide is produced, measured at 400 K and 100 kPa? (R = 8.31 J K−1 mol−1)

  1. A
    264 cm3
  2. B
    830 cm3
  3. C
    1480 cm3
  4. D
    1660 cm3
Show answer

Answer: B. n(CO2) = 2.50/100.1 = 0.0250 mol; V = nRT/p = 0.0250 × 8.31 × 400/100 000 = 8.30 × 10−4 m3 = 830 cm3. 1480 uses the Mr of CaO instead of CaCO3.

5. A reaction is exothermic when

  1. A
    more energy is absorbed in breaking bonds than is released in making bonds
  2. B
    the energy released in forming the new bonds exceeds the energy needed to break the old bonds
  3. C
    the activation energy is zero
  4. D
    the products have higher enthalpy than the reactants
Show answer

Answer: B. Breaking bonds always absorbs energy and forming bonds releases it. If more is released than absorbed, the surroundings get warmer and ΔH is negative.

6. Calcium hydride reacts with water: CaH2(s) + 2H2O(l) → Ca(OH)2(aq) + 2H2(g). Which statement is correct?

  1. A
    it is not a redox reaction because no element changes its oxidation number
  2. B
    hydrogen in CaH2 is reduced from +1 to 0 and hydrogen in water is oxidised from −1 to 0
  3. C
    calcium is oxidised from 0 to +2 and hydrogen in water is reduced
  4. D
    hydrogen in CaH2 is oxidised from −1 to 0 and hydrogen in water is reduced from +1 to 0
Show answer

Answer: D. In a metal hydride hydrogen is −1 (Ca is +2 throughout). The H− loses electrons to form H2 while H(+1) in water gains them, so hydrogen is both oxidised and reduced.

7. In aqueous solution: 2CrO42−(aq) (yellow) + 2H+(aq) ⇌ Cr2O72−(aq) (orange) + H2O(l). Aqueous sodium hydroxide is added to an orange equilibrium mixture. What is observed?

  1. A
    there is no change, because Na+ and OH− do not appear in the equation
  2. B
    the solution turns a deeper orange, because OH− removes H+ and the equilibrium moves to the right
  3. C
    the solution turns yellow, because OH− removes H+ and the equilibrium moves to the left
  4. D
    the solution turns yellow, because OH− reduces the dichromate ions
Show answer

Answer: C. OH− reacts with H+ to form water, lowering [H+]; the equilibrium moves left to replace H+, forming yellow CrO42−. No redox occurs (Cr stays +6).

8. A reaction has ΔH = −90 kJ mol−1 and an activation energy for the forward reaction of +60 kJ mol−1. What is the activation energy of the reverse reaction, in kJ mol−1?

  1. A
    +30
  2. B
    +60
  3. C
    +90
  4. D
    +150
Show answer

Answer: D. The products lie 90 kJ mol−1 below the reactants, and the transition state lies 60 above the reactants, so the reverse barrier is 60 + 90 = 150. +30 subtracts instead of adding.

9. Why is the radius of the P3− ion much larger than that of the Al3+ ion?

  1. A
    P3− has a greater nuclear charge
  2. B
    phosphorus is a non-metal
  3. C
    Al3+ has more electrons than P3−
  4. D
    P3− has three occupied electron shells, while Al3+ has only two
Show answer

Answer: D. Al3+ has lost its third shell (2,8), whereas P3− has gained electrons into it (2,8,8). The extra shell outweighs the larger nuclear charge of phosphorus.

10. Which equation shows the thermal decomposition of calcium nitrate?

  1. A
    Ca(NO3)2 → Ca(NO2)2 + O2
  2. B
    2Ca(NO3)2 → 2CaO + 4NO + 3O2
  3. C
    Ca(NO3)2 → CaO + 2NO2 + O2
  4. D
    2Ca(NO3)2 → 2CaO + 4NO2 + O2
Show answer

Answer: D. Group 2 nitrates decompose to the oxide, brown nitrogen dioxide and oxygen. O atoms: 12 on the left and 2 + 8 + 2 = 12 on the right. Ca(NO3)2 → CaO + 2NO2 + O2 has 7 O on the right, and forming a nitrite is not Group 2 behaviour.

11. What are the products when chlorine reacts with hot concentrated aqueous sodium hydroxide?

  1. A
    NaCl, NaClO and H2O
  2. B
    NaCl and H2O only
  3. C
    NaClO3, H2 and O2
  4. D
    NaCl, NaClO3 and H2O
Show answer

Answer: D. In hot alkali the chlorate(I) that forms disproportionates further, so the products are sodium chloride, sodium chlorate(V), NaClO3, and water.

12. Which statements about oxides of nitrogen are correct?
1 nitrogen monoxide is formed naturally during lightning storms
2 nitrogen monoxide forms in petrol engines because petrol contains nitrogen compounds
3 in a catalytic converter nitrogen monoxide is reduced to nitrogen

  1. A
    1, 2 and 3
  2. B
    1 and 2 only
  3. C
    2 and 3 only
  4. D
    1 and 3 only
Show answer

Answer: D. Lightning and hot engines both supply enough energy for N2 and O2 from the air to combine; the nitrogen does not come from the fuel, so statement 2 is wrong. NO (N +2) is reduced to N2 (N 0) in the converter.

Try 1131 more questions

Ways to practise 7 ways

When you get a question wrong, a short note called "The idea behind this" explains the topic it belongs to, with the rules to remember and a worked example.

Topics explained 51 topics

Each topic has a short explanation, the rules to remember, a worked example and practice questions.

Particles in the atom and atomic radiusIsotopesElectrons, energy levels and atomic orbitalsIonisation energyRelative masses of atoms and moleculesThe mole and the Avogadro constantFormulasReacting masses and volumes (of solutions and gases)Electronegativity and bondingIonic bondingMetallic bondingCovalent bonding and coordinate (dative covalent) bondingShapes of moleculesIntermolecular forces, electronegativity and bond propertiesDot-and-cross diagramsThe gaseous state: ideal and real gases and pV = nRTBonding and structureEnthalpy change, ΔHHess's lawRedox processes: electron transfer and changes in oxidation numberChemical equilibria: reversible reactions, dynamic equilibriumBrønsted–Lowry theory of acids and basesRate of reactionEffect of temperature on reaction rates and the concept of activation energyHomogeneous and heterogeneous catalystsPeriodicity of physical properties of the elements in Period 3Periodicity of chemical properties of the elements in Period 3Chemical periodicity of other elementsSimilarities and trends in the properties of the Group 2 metals, magnesium to bariumPhysical properties of the Group 17 elementsThe chemical properties of the halogen elements and the hydrogen halidesSome reactions of the halide ionsThe reactions of chlorineNitrogen and sulfurFormulas, functional groups and the naming of organic compoundsCharacteristic organic reactionsShapes of organic molecules; σ and π bondsIsomerism: structural isomerism and stereoisomerismAlkanesAlkenesHalogenoalkanesAlcoholsAldehydes and ketonesCarboxylic acidsEstersPrimary aminesNitriles and hydroxynitrilesAddition polymerisationOrganic synthesisInfrared spectroscopyMass spectrometry

All AS Level Chemistry rules on one pageAS Level Chemistry past papers: solve online

AS Level Chemistry mock tests: full length papers

5 fixed papers of 40 questions in 60 minutes, in the pattern of the real paper.

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AS Level Chemistry: frequently asked questions

Is this AS Level Chemistry test free?

Yes. Every test, answer and explanation is free, and you do not need an account. Sign in only if you want your results kept across devices.

How many AS Level Chemistry questions are there?

1143 MCQs with answers, covering 22 chapters of the syllabus. Each test draws new questions, so you can practise many times.

Are these AS Level Chemistry past paper questions?

No. The 1143 MCQs are our own, written to the syllabus in the style of the exam. The 28 Cambridge past papers are listed separately inside the test.

How is the test marked?

Instantly. You see your score, the right answer and an explanation for every question, and the topics to work on next. Questions you got wrong are saved so you can retry them.

Can I practise one chapter or only my weak topics?

Yes. Pick a chapter, build your own test from chosen topics, or practise your weakest topics and your past mistakes.

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