Gases :  Kinetic Molecular Theory
  • Gases are composed of a many particles that behave like hard spherical objects in a state of constant, random motion. 
  • These particles move in a straight line until they collide with another particle or the walls of the container. 
  • These particles are much smaller than the distance between particles, therefore the volume of a gas is mostly empty space and the volume of the gas molecule themselves is negligible. 
  • There is no force of attraction between gas particles or between the particles and the walls of the container. 
  • Collisions between gas particles or collisions with the walls of the container are elastic.  That is, none of the energy of the gas particle is lost in a collision. 

  • The average kinetic energy of a collection of gas particles is dependent only upon the temperature of the gas. 
    In short, the key parts are: 
    1. constant random motion 
    2. straight line motion 
    3. negligible volume 
    4. no forces of attraction 
    5. elastic collisions 

    Check out this Animated Molecular Model for an Ideal Gas!

    The Relationship Between P and n

    Boyle's Law

    Amonton's Law

    Charles' Law

    Avogadro's Hypothesis

    Dalton's Law of Partial Pressures