Lesson T1.2.1

T1.2.1 Changes of state explained by particles Quiz: KS3 Chemistry, Unit 1

20 questions

Written by Revision Ninja · Last reviewed 11 October 2026

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Lesson T1.2.1, Changes of state explained by particles: 20 multiple choice questions for the KS3 Chemistry (National Curriculum), Unit 1: The particulate nature of matter, written with Revision Ninja.

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The 20 questions

  1. What happens to the particles when a solid melts?

    • They gain energy and vibrate more until they can move past each other
    • They lose energy and become fixed in place, locking into a regular rigid pattern
    • They stop vibrating and join into a rigid frame that holds the shape firmly
    • They break into smaller atoms that vibrate more strongly but stay in place

  2. What is the name of the change when a liquid turns into a gas at its surface?

    • Evaporation
    • Freezing
    • Condensation
    • Sublimation

  3. What is the name of the change when a gas turns into a liquid?

    • Evaporation, the change of liquid into gas that happens at the surface
    • Sublimation, the change of solid straight into gas without a liquid
    • Melting, the change of solid into liquid when it gains energy
    • Condensation, the change of gas into liquid when it loses energy

  4. Which change of state is the reverse of melting?

    • Freezing
    • Sublimation
    • Condensation
    • Boiling

  5. Which change of state takes a solid straight to a gas?

    • Sublimation
    • Freezing
    • Condensation
    • Evaporation

  6. During melting, what happens to the temperature of a pure substance?

    • It stays at the melting point while it melts
    • It doubles every minute while the sample is being heated in the flask
    • It falls steadily throughout the melting process as the sample cools down
    • It rises steadily throughout the whole melting process as heat is applied

  7. Which change is a reversible physical change?

    • Cooking an egg so it cannot be restored to its raw, runny state at all
    • Melting ice to water and then freezing it back
    • Burning wood to ash and gas, which cannot be turned back into the original wood
    • Rusting iron into iron oxide, a new substance that cannot be turned back easily

  8. What happens to particles during boiling?

    • Particles gain enough energy to escape as a gas throughout the liquid
    • Particles lose energy and pack closer together until they form a solid in the liquid
    • Particles break into smaller particles that float up and escape from the surface
    • Particles join together to form a solid and sink to the bottom of the container

  9. Water in a puddle disappears on a warm sunny day. Which change of state is this?

    • Condensation
    • Melting
    • Freezing
    • Evaporation

  10. Dew forms on grass overnight. Which change of state is responsible?

    • Melting of frost on the grass as the air warms up in the morning sun
    • Condensation of water vapour in the air
    • Freezing of water on the surface of the grass as the air gets colder
    • Sublimation of ice from the ground, straight into vapour in the air

  11. A block of ice is left on a table and gradually disappears without melting into a puddle. Which change best explains this?

    • Freezing of the air around the ice so that the block is covered in frost
    • Sublimation, where ice changes directly into water vapour
    • Evaporation of liquid water from the melted ice that leaves the table dry
    • Condensation of the surrounding air onto the surface of the cold ice block

  12. Why does a liquid evaporate even below its boiling point?

    • The particles change into a solid at the surface, which then evaporates away
    • All particles reach the boiling point at once, so the liquid evaporates quickly
    • The particles stop moving and fall to the bottom where they stay trapped
    • Some particles at the surface have enough energy to escape

  13. Which change of state requires the particles to lose energy?

    • Boiling, when a liquid gains energy and turns into a gas throughout the liquid
    • Condensation, when a gas gives out energy and turns into a liquid
    • Evaporation, when a liquid gains energy and turns into a gas at its surface
    • Melting, when a solid gains energy and turns into a liquid

  14. When a gas cools and forms droplets on a cold window, what happens to the particles?

    • They become larger and turn into a solid that sticks to the cold window
    • They lose energy, slow down and come closer together as a liquid
    • They gain energy, speed up and move further apart as they become a gas again
    • They split into atoms and float away from the window into the room

  15. A student heats a solid and it expands before melting. Why?

    • Particles vibrate more strongly and take up more space
    • Particles change into atoms that are smaller and more tightly bonded together
    • Particles shrink and pack tighter together as the solid warms up slightly
    • Particles stop moving and form bonds that hold the solid in a fixed shape

  16. Why does boiling happen throughout a liquid, not just at its surface?

    • The container heats only the surface of the liquid, so the bottom stays cold
    • Bubbles of vapour form inside the liquid where particles have enough energy
    • Bubbles of solid form inside the liquid as it cools, which float to the surface
    • Particles at the bottom are heavier and sink, so they are the first to boil

  17. Which statement describes the energy and arrangement of particles in the gas state compared with the liquid state?

    • Gas particles have less energy and are closer together than liquid particles
    • Gas particles are fixed while liquid particles move freely
    • Gas particles have the same energy but are packed more tightly
    • Gas particles have more energy and are further apart than liquid particles

  18. A substance melts at 0 °C and boils at 100 °C. What state is it in at 50 °C?

    • Gas
    • Liquid
    • Solid
    • A mixture of solid and gas

  19. What is the melting point of a pure substance?

    • The temperature at which it changes from liquid to gas under normal pressure
    • The temperature at which it becomes a mixture when another substance is added
    • The temperature at which it changes from solid to liquid
    • The temperature at which it stops conducting heat and becomes an insulator

  20. Which energy change happens when a substance freezes?

    • No energy is transferred during freezing, so the substance stays the same
    • Energy is taken in by the substance, so it warms up as it freezes solid
    • Energy is transferred away from the substance
    • Energy is created inside the substance and it becomes warmer as it freezes

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