Apply kinetic theory to solids and liquids?

In summary, the conversation discusses the use of the kinetic theory to explain the properties of solids and liquids in a chemistry textbook. The conversation raises the question of whether the kinetic theory should only be used for gases, as one of its postulates states that particles do not exert forces on each other. The book disabled this axiom and explained that forces increase as particles get closer. However, it is argued that this is not good or proper. The conversation also mentions the use of the free electron theory in metals as another example of a simplified model that can be used to understand materials. It is concluded that the kinetic theory is not only limited to gases, but can also provide qualitative behavior for solids and liquids.
  • #1
pivoxa15
2,255
1
My chemistry textbook tries to explain the properties of solids and liquids with the kinetic theory. Is this not good? Should only gases be explained by the kinetic theory since one of the postulates in this theory is that particles exert no forces on each other. The book had to disable this axiom when explaining solids and liquids and said that the forces increase the closer the particles are. But cancelling an axiom is not good or improper isn't it? But theory should be used to explain solids and liquids in general?
 
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  • #2
The assumption (I wouldn't call it an axiom) that the particles do not interact is just a starting point for learning how things really work. For example the free electron theory in metals does not work too well with real materials but it's easy to exctract some quantitatively correct results out of it to get one started in learning about metals.
 
  • #3
I'd say "transport theory" is not only about "kinetic theory of gases". Yes, the simple models of noninteracting quantum gases could provide qualitative behavior, since the general eqns from transport theory (either semiclassical or purely quantum) cannot be solved for solids, nor liquids.

Daniel.
 

1. What is kinetic theory?

Kinetic theory is a scientific theory that explains the behavior of particles in matter. It states that all matter is made up of tiny particles that are constantly in motion, and that the temperature of a substance is directly related to the average kinetic energy of its particles.

2. How does kinetic theory apply to solids and liquids?

In solids, the particles are tightly packed together and vibrate in a fixed position. As the temperature increases, the particles vibrate more vigorously, causing the solid to expand. In liquids, the particles are less tightly packed and can move around each other. As the temperature increases, the particles move faster, causing the liquid to expand and take on the shape of its container.

3. What is the relationship between temperature and kinetic energy in solids and liquids?

According to kinetic theory, temperature and kinetic energy are directly proportional in solids and liquids. This means that as the temperature increases, the average kinetic energy of the particles also increases.

4. How does kinetic theory explain the different properties of solids and liquids?

The properties of solids and liquids, such as density, viscosity, and compressibility, can be explained by the behavior of their particles according to kinetic theory. For example, the tightly packed particles in solids make them more dense and less compressible, while the more loosely packed particles in liquids make them less dense and more compressible.

5. Can kinetic theory be applied to gases as well?

Yes, kinetic theory can also be applied to gases. In gases, the particles are widely spaced and move freely, colliding with each other and the walls of their container. The temperature of a gas is directly related to the average kinetic energy of its particles, just like in solids and liquids.

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