chapter 8

• solid

  have the highest densities

  have a fixed volume and a fixed shape

  arrangement

  • particles are closely packed together in a regular pattern. the particles in solids have the least energy among the three states of matter

  motion

  • particles vibrate about their fixed positions. they are held in position by strong attractive forces between particles
• liquid

  have slightly lower densities than solids

  have a fixed volume and no fixed shape

  arrangement

  • particles are slightly less closely packed than in solids and arranged in irregular pattern

  motion

  • particles slide over one another throughout the liquid without fixed positions. the attractive forces holding them together are weaker than in solid
• gas

  have the lowest densities

  have no fixed volume as it is compressible and no fixed shape

  arrangement

  • particles are very far apart from one another in an irregular pattern. the particles in gases have the most energy among the three states of matter

  motion

  • particles move freely in any direction. attractive forces between particles are weak
• brownian motion


  particles moving constantly and randomly in all directions
• temperature

  as temperature increases, the average kinetic energy of the particles in a body increases.

  the concept above is only applicable to a collection of particles, never a single particle itself

  when a substance such as water is heated, the energy in the kinetic store of the particles increases, causing particles to move and vibrate at a faster rate. when the thermometer comes into contact with the water, the more energetic particles in the water transfers some of the energy to the less energetic particles i the thermometer through solution
• pressure


  at the particle level, pressure is the average force exerted by the particles per unit area

  when a gas particle collides with the inner walls of a container, it exerts a force on the wall. the reaction force causes the particle to bounce back from the wall