Particles and states of matter Edexcel International GCSE Physics revision

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In plain words

Everything is made of tiny particles that never stop moving. In a solid they jiggle on the spot; in a liquid they slide around each other; in a gas they fly about freely. Heat something and its particles move faster.

Three things to know

  1. In a solid, particles vibrate about fixed positions in a regular pattern. In a liquid they are close together but move past each other. In a gas they are far apart and move quickly at random.
  2. Gas pressure is caused by particles hitting the walls of the container.
  3. Brownian motion (smoke specks jiggling in air) is evidence that fast, invisible particles are hitting them.

Tips and tricks

  • Describe particles with two words every time: their arrangement and their motion.
  • Gas pressure answers need "particles collide with the walls". Hotter means faster, so the collisions are more frequent and harder.
6 questions, about 2 minutes.

It lands in your notebook with its questions as flashcards.

Particles and states of matter: 6 questions and answers

These are the quiz’s questions. Do the quiz first, then come back here for the ones that got you.

  1. In which state are particles furthest apart?
    • solid
    • liquid
    • gas (the answer)
    • they are the same in all three

    Gas particles are widely spaced.

  2. What causes the pressure of a gas?
    • particles hitting each other
    • particles hitting the container walls (the answer)
    • the weight of the particles
    • particles expanding

    Each collision with a wall pushes on it.

  3. Which describes particles in a solid?
    • far apart and moving quickly
    • close together and sliding past each other
    • close together and vibrating about fixed positions (the answer)
    • not moving at all

    They stay in place but vibrate.

  4. What does Brownian motion show?
    • Smoke is lighter than air.
    • Air is made of moving particles. (the answer)
    • Smoke particles are alive.
    • Light pushes small particles.

    The visible specks are being knocked about by invisible molecules.

  5. A gas is heated in a sealed, rigid container. What happens to its particles?
    • They get bigger.
    • They move faster. (the answer)
    • They move closer together.
    • There are more of them.

    Heating gives the particles more kinetic energy.

  6. Why can liquids flow but solids cannot?
    • Liquid particles are smaller.
    • Liquid particles can move past each other. (the answer)
    • Liquid particles are further apart than gas particles.
    • Liquid particles do not attract each other.

    In a solid the particles are held in fixed positions.

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