The Nature of Gases

When you look around, you don't see or notice the gases around you.  It appears that we are surrounded by empty space, but there are actually molecules of gases and particles in constant motion.

All gases:

1. Gases have mass.
2. Gases are compressible. The particles can be pushed closer together, decreasing the volume.
3. Gases will expand their container. The particles can move farther part, increasing the volume.
4. Gases diffuse. The particles expand to fill their container, therefore they mix and equally distribute themselves throughout the space.
5. Gases exert pressure.  Gases apply a force by colliding with a surface.
6. Pressure is related to temperature.  Temperature is average kinetic energy.  The higher the temperature, the more energy, therefore momentum each pas particle has.

The Kinetic Molecular Theory (KMT) states that gases are composed of tiny particles in constant motion. In reality, gases are effected by many variables.  Some have a large effect like temperature, while others have very effect, such as intermolecular forces.  In science, we simplify this concept by ignoring the smaller influences.  We call this an ideal gas.

Ideal gasses are assumed to:

1. be composed of small hard particles.
2. have an insignificant volume in comparison to the space they occupy.
3. have only empty space between the particles.
4. have no attractive or repulsive forces between the particles.
5. are in constant, random, straight line motion.
6. only change path when they collide with each other or the walls of their container.