Kinetic-Molecular Theory of Matter
The Kinetic-Molecular Theory (KMT) of matter uses a set of assumptions and approximations made about matter at the atomic and molecular levels to explain behavior of matter at the macroscopic (everyday) level. Some of the major assumptions and approximations made by the KMT are as follows.
- All matter is composed of particles (atoms and/or molecules).
- Each atom or molecule can be considered to be a point-particle. In other words, the KMT says that any atom or molecule has approximately no volume. Note: This is just an approximation.
- The particles in a gas are far enough apart to exert no forces on each other. Again, this is only an approximation.
- The particles in a liquid are close enough together to exert forces on one another but are still able to move about relative to one another.
- The particles in a solid are close enough together to exert forces on one another and are unable to move around relative to one another.
- The particles in a substances are always moving.
- The particles in a substance are constantly bumping into each other.
- The particles in a substance undergo totally elastic collisions. In other words, the total kinetic energy of the particles in a substance remains the same no matter the number of collisions of particles in the substance. Again, this is only an approximation.
- The temperature of a substance is directly proportional to the average translational kinetic energy of the particles in the substance. In other words, the faster the particles in a substance are moving, the higher the temperature of the substance.