Particle/kinetic theory

• What are the three states of matter?

  Solid, liquid, and gas
• What does particle theory explain?

  How particles behave in different states
• How are particles modeled in particle theory?

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

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

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

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

  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
• What are the forces of attraction like in liquids?

  Weak forces of attraction
• How are particles arranged in liquids?

  Randomly, but fairly compact
• Why do liquids have a definite volume?

  Particles tend to stick together
• What happens when a liquid is heated?

  Particles 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 become gas
• 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?

  They can travel in any direction
• What happens when a gas is heated?

  Particles gain energy and move 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 happens when a gas is cooled down?

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

  Particles form more bonds and freeze
• What happens to mass in a closed system during state changes?

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

  Solids are highest, gases lowest
• What are the changes in state of matter?

  • Solid to liquid: Melting
  • Liquid to gas: Boiling/Evaporation
  • Gas to liquid: Condensation
  • Liquid to solid: Freezing
• What are the characteristics of solids, liquids, and gases?

  • Solids: Fixed shape and volume, strong attraction
  • Liquids: Definite volume, shape changes, weak attraction
  • Gases: No definite shape or volume, very weak attraction