states of matter

• Solid


  State of matter where particles are held close together in a fixed position to form a regular lattice structure
• Liquid


  State of matter where particles are free to move around but are held together by weak forces of attraction
• Gas


  State of matter where particles are free to move around with very weak forces of attraction between them
• Melting


  Solid particles gain energy, vibrate more, and break free of bonds to become a liquid
• Boiling/Evaporation


  Liquid particles gain enough energy to break bonds and become a gas
• Condensation


  Gas particles lose energy and form bonds to become a liquid
• Freezing


  Liquid particles lose enough energy for bonds to form and become a solid
• Particle theory model


  • Particles are small solid inelastic spheres
  • Explains how particles behave in each state of matter
• The particle theory model is a simplification and doesn't perfectly represent reality</b>
• In reality, particles are atoms, ions or molecules, not solid inelastic spheres
• The particle theory model does not include details about the forces between particles
• Despite its limitations, the particle theory model is a useful simplification for understanding the states of matter
• In solids, the particles are held together by strong forces so they vibrate around fixed positions
• In liquids, the particles have weaker bonds between them so they can move past one another but still remain close to their original position
• solid- 3 characteristics 


  have fixed volume, fixed shale and particles vibrate around fixed positions
• liquid- 3 characteristics 


  have fixed volume, not fixed shale (can change shape), particles can move over eachother
• gases- 3 characteristics 


  no fixed shape, no fixed volume, particles far apart and move quickly in all directions
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• State change


  The amount of energy needed to change state from solid to liquid and from liquid to gas depends on the strength of the forces between the particles
• Strength of forces between particles

  The stronger the forces of attraction, the more energy that is needed to overcome them for a state change to occur
• Strength of forces between particles

  The higher the melting point and boiling point of the substance
• Physical change


  When matter changes from one state to another due to changes in temperature or pressure, the change is called an interconversion of state. It involves changes in the forces between the particles, but the particles themselves and the chemical properties remain the same. Physical changes are relatively easy to reverse as no new substance is formed.
• Terms to describe state changes

  • Melting
  • Boiling
  • Freezing
  • Evaporation
  • Condensation
  • Sublimation
• Melting


  When a solid changes into a liquid. It requires heat energy which transforms into kinetic energy, allowing the particles to move. It occurs at a specific temperature known as the melting point which is unique to each pure solid.
• Boiling


  When a liquid changes into a gas. This requires heat which causes bubbles of gas to form below the surface of a liquid, allowing for liquid particles to escape from the surface and from within the liquid. It occurs at a specific temperature known as the boiling point which is unique to each pure liquid.
• Freezing


  When a liquid changes into a solid. This is the reverse of melting and occurs at exactly the same temperature as melting, hence the melting point and freezing point of a pure substance are the same. It requires a significant decrease in temperature (or loss of thermal energy) and occurs at a specific temperature which is unique for each pure substance.
• Evaporation


  When a liquid changes into a gas. Evaporation occurs only at the surface of liquids where high energy particles can escape from the liquids surface at low temperatures, below the boiling point of the liquid. The larger the surface area and the warmer the liquid/surface, the more quickly a liquid can evaporate. Evaporation occurs over a range of temperatures, but heating will speed up the process as particles need energy to escape from the surface.
• Condensation


  When a gas changes into a liquid, usually on cooling. When a gas is cooled its particles lose energy and when they bump into each other, they lack energy to bounce away again, instead grouping together to form a liquid.
• Sublimation


  When a solid changes directly into a gas. This happens to only a few solids, such as iodine or solid carbon dioxide. The reverse reaction also happens and is called desublimation or deposition.
• State


  • Solid
  • Liquid
  • Gas
• Solid


  • Arrangement of particles: Regular
  • Movement of particles: Vibrate about a fixed position
  • Closeness of particles: Very close