AS Level Chemistry chapter 4: States of matter MCQs with answers

By Team Megalecture · Updated 4 Nov 2026

44 exam-style questions on States of matter, each with the answer and a short explanation. Ten of them are below to try. The chapter test draws ten fresh questions each time and is marked the moment you finish, with your score by topic.

44 questions · 2 topics · 10 per test

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What chapter 4 covers

Ten States of matter questions with answers

Try each one, then open the answer. These ten stay the same; the test draws new ones every time.

1. 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.

2. Why does solid sodium chloride not conduct electricity, although molten sodium chloride does?

  1. A
    in the solid the ions are held in fixed positions; in the melt they are free to move
  2. B
    the solid has no delocalised electrons, but the melt does
  3. C
    the solid contains molecules, but the melt contains ions
  4. D
    electrons can move only when the ions are hot
Show answer

Answer: A. Ionic compounds conduct by movement of ions. In the solid lattice the ions cannot move; melting frees them to carry charge. There are no delocalised electrons in either state.

3. What volume is occupied by 0.100 mol of an ideal gas at 400 K and 200 kPa?

  1. A
    0.831 dm3
  2. B
    3.32 dm3
  3. C
    1.66 dm3
  4. D
    16.6 dm3
Show answer

Answer: C. V = nRT/p = (0.100 × 8.31 × 400)/200 000 = 332.4/200 000 = 1.66 × 10−3 m3 = 1.66 dm3. Using 24.0 dm3 mol−1 would be wrong because these are not room conditions.

4. A gas is studied at a temperature just above its boiling point. The measured value of pV is less than nRT. What is the best explanation?

  1. A
    the molecules have zero volume
  2. B
    the molecules repel each other strongly
  3. C
    the molecules move faster than an ideal gas would
  4. D
    attractions between the molecules reduce the force with which they strike the walls
Show answer

Answer: D. Near condensation the molecules are slow and attract one another, pulling back molecules about to hit a wall; the pressure is lower than the ideal value, so pV < nRT.

5. Which description of the structure of solid copper is correct?

  1. A
    a lattice of positive copper ions in a sea of delocalised electrons
  2. B
    a lattice of copper atoms held by covalent bonds
  3. C
    a lattice of Cu2+ and Cu− ions held by ionic bonds
  4. D
    Cu2 molecules held by weak intermolecular forces
Show answer

Answer: A. Copper is a giant metallic lattice: positive ions in fixed positions with outer electrons delocalised throughout, attracted to all the ions.

6. 0.320 g of a volatile liquid is completely vaporised. The vapour occupies 120 cm3 at 373 K and 101 kPa. What is the relative molecular mass of the liquid? (R = 8.31 J K−1 mol−1)

  1. A
    0.0818
  2. B
    21.9
  3. C
    81.8
  4. D
    81 800
Show answer

Answer: C. Mr = mRT/pV = 0.320 × 8.31 × 373 / (101 000 × 1.20 × 10−4) = 81.8. Using 100 °C instead of 373 K gives 21.9.

7. Which describes the structure of solid iodine?

  1. A
    a simple molecular lattice of I2 molecules held together by instantaneous dipole–induced dipole forces
  2. B
    a giant covalent lattice of iodine atoms
  3. C
    a giant ionic lattice of I+ and I− ions
  4. D
    a metallic lattice with delocalised electrons
Show answer

Answer: A. Iodine is a molecular solid: strong covalent bonds inside each I2 molecule, but only weak id-id forces between molecules, which is why it sublimes easily.

8. Why does a real gas deviate from ideal behaviour at very high pressure?

  1. A
    the volume of the molecules themselves becomes a significant fraction of the container volume
  2. B
    the molecules move faster at high pressure
  3. C
    the molecules break into atoms
  4. D
    collisions with the walls become inelastic
Show answer

Answer: A. The ideal model assumes zero particle volume; when molecules are squeezed close together their own volume is no longer negligible (and attractions between them also matter more).

9. A sample of gas occupies 2.00 dm3 at 27 °C and 100 kPa. It is heated to 177 °C and compressed to 1.50 dm3. What is its new pressure?

  1. A
    113 kPa
  2. B
    133 kPa
  3. C
    200 kPa
  4. D
    874 kPa
Show answer

Answer: C. p2 = 100 × (450/300) × (2.00/1.50) = 200 kPa. Using the Celsius temperatures 177/27 gives 874 kPa; inverting the volume ratio gives 113 kPa.

10. 0.0500 mol of an ideal gas occupies 1.50 dm3 at 150 kPa. What is the temperature of the gas? (R = 8.31 J K−1 mol−1)

  1. A
    0.541 K
  2. B
    268 K
  3. C
    541 K
  4. D
    814 K
Show answer

Answer: C. T = pV/nR = (150 000 × 1.50 × 10−3)/(0.0500 × 8.31) = 541 K. 268 is this value in °C, not K.

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States of matter: questions students ask

How many States of matter MCQs are there?

44, each with the answer and a short explanation, across 2 topics: The gaseous state: ideal and real gases and pV = nRT, Bonding and structure. Every chapter test draws ten of them, so you can take it many times.

Is the AS Level Chemistry chapter 4 test free?

Yes. The test, the answers and the explanations are free and need no sign-up. Sign in only if you want your scores kept across devices.

How is the chapter test marked?

The moment you press Finish: your score, the right answer and an explanation for every question, and the ones you got wrong saved in My mistakes to retry.

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