Changes of state and internal energy: Particle model of matter: Physics: GCSE (9:1)

• State of matter

  A physical property that describes matter as a solid, liquid, or gas

  
• Change of state


  A physical change of a substance from one state of matter to another

  
• Melting


  The change of state from a solid to a liquid

  
• Boiling

  Change of state from a liquid to a gas (occurs at a fixed temperature known as the boiling point)

  
• Evaporating


  Change of state from a liquid to a gas (that occurs at at the surface of a liquid below it's boiling point)

  
• Condensing


  Change of state from a gas to a liquid

  
• Sublimation


  The change of state from a solid to a gas (or a gas to a solid)

  
• Freezing


  The change of state from a liquid to a solid

  
• Melting point


  The temperature at which a solid becomes a liquid (when being heated) or a liquid becomes a solid (when being cooled)

  
• Boiling point

  The temperature at which a liquid becomes a gas (when being heated) or a gas becomes a liquid (when being cooled)

  
• Physical change

  When a substance recovers its original properties if the change is reversed

  
• Conservation of mass


  Mass cannot be created or destroyed during a physical or chemical change

  
• Internal energy

  The total kinetic energy and potential energy of all the particles (atoms and molecules) that make up a system
• The energy change when a substance is heated or cooled

  The internal energy of the particles increases or decreases
• The energy change when a substance's temperature changes

  The kinetic energy of the the particles increases or decreases
• The energy change when a substance changes state


  The particles are gain or lose potential energy because bonds between them break or form