Particle Theory / States of Matter

• What are the three states of matter ?

  Solid, liquid, and gas
• What model is used to explain the behavior of particles in different states of matter?

  Particle theory or kinetic theory
• How are particles in solids described in the particle theory?

  As small solid inelastic spheres
• What holds the particles in a solid together?

  Strong forces of attraction
• What structure do particles in solids form?

  A regular lattice structure
• Why do solids have a definite shape and volume?

  Particles are fixed in position
• How do particles in solids behave?

  They vibrate around fixed positions
• What happens to solid particles when heated?

  They gain energy and vibrate more
• What is the melting point?

  The temperature where solids melt
• What occurs at the melting point?

  Particles break free of their bonds
• How are particles arranged in liquids?

  Randomly, but fairly compact
• What allows liquids to flow?

  Weak forces of attraction between particles
• What happens to liquid particles when heated?

  They gain energy and move faster
• What is the boiling point?

  The temperature where liquids boil
• What occurs at the boiling point?

  Particles break bonds and evaporate
• How do gas particles behave?

  They move freely and randomly
• Why do gases not have a definite shape or volume?

  They fill the container they are in
• What does random motion of gas particles mean?

  Particles can travel in any direction
• What happens when gas particles are heated?

  They gain energy and travel faster
• What happens to gas in an expandable container when heated?

  The gas expands
• What happens to gas in a fixed container when heated?

  The pressure increases
• What occurs when gas is cooled down?

  Particles form bonds and condense
• What happens when a liquid is cooled further?

  Particles form more bonds and freeze
• What is the relationship between changes in state and mass in a closed system?

  Mass remains the same
• How does density vary among the states of matter?

  Solids are highest, gases lowest
• What are the key characteristics of solids, liquids, and gases?

  • Solids: Fixed shape and volume, strong attraction, regular lattice.
  • Liquids: Definite volume, shape changes, weak attraction, random arrangement.
  • Gases: No definite shape or volume, very weak attraction, fill container.
• What are the processes of changing states of matter?

  1. Melting: Solid to liquid at melting point.
  2. Boiling: Liquid to gas at boiling point.
  3. Condensation: Gas to liquid when cooled.
  4. Freezing: Liquid to solid when cooled further.