Paper 2 States of Matter MCQ Practice
10 multiple-choice questions on states of matter for IGCSE Chemistry Paper 2. Covers kinetic particle theory, changes of state, diffusion, and gas behaviour.
Published by IGCSEChemistry.com.my
Chemistry teaching team: K. S. Tan (15+ years teaching IGCSE Chemistry) and Ms Yash (10+ years teaching IGCSE Chemistry) and Ms Kartini (15+ years teaching IGCSE Chemistry).
Mapped to Cambridge IGCSE Chemistry 0620 (2026–2028). Last updated 2026-08-19.
Ten multiple-choice questions in the style of IGCSE Chemistry Paper 2. Choose the best answer for each, then check the mark scheme.
Question 1
Which statement correctly describes the particles in a liquid?
A. They are in fixed positions and vibrate about those positions. B. They are close together and move randomly, sliding past each other. C. They are far apart and move quickly in all directions. D. They are in a regular arrangement with strong forces between them.
Answer
B
In a liquid, particles are close together but not in fixed positions. They have enough energy to slide past one another, which is why liquids flow and take the shape of their container. Option A describes a solid, C describes a gas, and D describes a solid lattice.
Question 2
A drop of ink is placed in cold water. After 20 minutes the water is uniformly coloured. What is this process called?
A. Osmosis B. Evaporation C. Diffusion D. Filtration
Answer
C
Diffusion is the net movement of particles from a region of higher concentration to a region of lower concentration as a result of their random motion. The ink particles spread through the water until the concentration is equal throughout.
Question 3
At which temperature change does a pure substance change from liquid to gas at standard pressure?
A. Melting point B. Boiling point C. Freezing point D. Sublimation point
Answer
B
The boiling point is the temperature at which a liquid changes to a gas throughout the bulk of the liquid. The melting point is solid to liquid. Freezing is the reverse of melting. Sublimation is solid directly to gas.
Question 4
Which row correctly compares solids, liquids, and gases?
| Arrangement | Movement | |
|---|---|---|
| A | Solid: regular; Liquid: random; Gas: random | Solid: vibrate; Liquid: move freely; Gas: vibrate |
| B | Solid: regular; Liquid: random; Gas: random | Solid: vibrate; Liquid: slide; Gas: move fast and randomly |
| C | Solid: random; Liquid: regular; Gas: random | Solid: vibrate; Liquid: vibrate; Gas: move fast |
| D | Solid: regular; Liquid: regular; Gas: random | Solid: slide; Liquid: slide; Gas: move fast |
Answer
B
Solids have a regular arrangement with particles vibrating about fixed positions. Liquids have a random arrangement with particles sliding past each other. Gases have a random arrangement with particles moving at high speed in all directions. Option A incorrectly says gas particles vibrate.
Question 5
During evaporation from the surface of a liquid, which particles escape?
A. The smallest particles B. The particles with the most kinetic energy C. The particles closest to the centre D. The particles with the least kinetic energy
Answer
B
Evaporation occurs when particles at the surface have enough kinetic energy to overcome the attractive forces holding them in the liquid. These are the fastest-moving particles. This is why evaporation causes cooling --- the average kinetic energy of the remaining particles decreases.
Question 6
Bromine vapour is placed in the lower of two gas jars. When the cover slip is removed, the upper jar slowly turns brown. What does this demonstrate about gas particles?
A. They are attracted to each other. B. They always move upwards. C. They are in constant random motion. D. They expand when heated.
Answer
C
The bromine particles spread into the upper jar because they are in constant random motion, moving in all directions. They do not simply float upwards --- bromine is denser than air. The fact that they move upwards against gravity is evidence that gas particles move randomly, not in a directed way.
Question 7
Which change of state is exothermic?
A. Melting B. Boiling C. Evaporation D. Condensation
Answer
D
Condensation (gas to liquid) is exothermic because energy is released to the surroundings as particles slow down and intermolecular forces form. Melting, boiling, and evaporation are all endothermic --- they require energy input to overcome attractive forces between particles.
Question 8
A solid is heated at a constant rate. Which statement is correct about the temperature during melting?
A. The temperature rises more slowly. B. The temperature remains constant. C. The temperature falls briefly. D. The temperature rises more quickly.
Answer
B
During a change of state, the temperature remains constant even though energy is being supplied. The energy is used to overcome intermolecular forces rather than to increase the kinetic energy of the particles. This is why heating curves show flat sections at the melting and boiling points.
Question 9
Which substance undergoes sublimation when heated at atmospheric pressure?
A. Sodium chloride B. Water C. Iodine D. Iron
Answer
C
Iodine sublimes --- it changes directly from a solid to a purple vapour without passing through a liquid phase at atmospheric pressure. Sodium chloride and iron melt to form liquids before boiling. Water melts at 0 degC before boiling at 100 degC.
Question 10
Diffusion is faster in gases than in liquids. Which statement best explains this?
A. Gas particles are larger than liquid particles. B. Gas particles are further apart and move faster, so there are fewer collisions to slow them down. C. Liquid particles do not move. D. Gas particles are heavier and push through more easily.
Answer
B
In gases, particles are far apart and move at high speeds. A diffusing particle travels further between collisions, so the net movement from high to low concentration is rapid. In liquids, particles are close together, leading to frequent collisions that slow the progress of a diffusing particle. Option C is wrong because liquid particles do move, and options A and D are factually incorrect.
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