what is the kinetic-molecular theory?

Answer 1

Kinetic theory attempts to explain macroscopic properties of gases, such as pressure, temperature, or volume, by considering their molecular composition and motion. Essentially, the theory posits that pressure is due not to static repulsion between molecules, as was Isaac Newton's conjecture, but due to collisions between molecules moving about with a certain velocity. Kinetic theory is also known as kinetic-molecular theory or collision theory.

Postulates
The kinetic theory for ideal gases makes the following assumptions:
* The gas consists of very small particles, each of which has a mass.
* These molecules are in constant, random motion. The rapidly moving particles constantly collide with each other and with the walls of the container.
* The collisions of gas particles with the walls of the container holding them are perfectly elastic.
* The interactions between molecules are negligible. They exert no forces on one another except during collisions.
* The total volume of the individual gas molecules added up is negligible compared to the volume of the container. This is equivalent to stating that the average distance separating the gas particles is relatively large compared to their size.
* The average kinetic energy of the gas particles depends only on the temperature of the system.
* Quantum-mechanical effects are negligible. This means that the interparticle distance is much larger than the thermal de Broglie wavelength and the molecules can be treated as classical objects.

In addition, if the gas is in a container, the collisions with the walls are assumed to be instantaneous and elastic.

More modern developments relax these assumptions and are based on the Boltzmann equation. These can accurately describe the properties of dense gases, because they include the volume of the molecules. The necessary assumptions are the absence of quantum effects, molecular chaos and small gradients in bulk properties. Expansions to higher orders in the density are known as virial expansions. The definitive work is the book by Chapman and Enskog but there have been many modern developments and there is an alternative approach developed by Grad based on moment expansions. In the other limit, for extremely rarefied gases, the gradients in bulk properties are not small compared to the mean free paths. This is known as the Knudsen regime and expansions can be performed in the Knudsen number.

The kinetic theory has also been extended to include inelastic collisions in granular matter by Jenkins and others.

You could get more information from the link below...

Answer 2

Kinetic Molecular Theory

The Kinetic Molecular Theory explains the forces between molecules and the energy that they possess. This theory has 3 basic assumptions.

Matter is composed of small particles (molecules). The measure of space that the molecules occupy (volume) is derived from the space inbetween the molecules and not the space the molecules contain themselves.
The molucules are in constant motion. This motion is different for the 3 states of matter.
Solid - Molecules are held close to each other by their attractions of charge. They will bend and/or vibrate, but will stay in close proximity.
Liquid - Molecules will flow or glide over one another, but stay toward the bottom of the container. Motion is a bit more random than that of a solid.
Gas - Molecules are in continual straightline motion. The kinetic energy of the molecule is greater than the attractive force between them, thus they are much farther apart and move freely of each other.
When the molecules collide with each other, or with the walls of a container, there is no loss of energy.

The Kinetic Molecular Theory is a single set of descriptive characteristics of a substance known as the Ideal Gas. All real gases require their own unique sets of descriptive characteristics. Considering the large number of known gases in the World, the task of trying to describe each one of them individually would be an awesome task. In order to simplify this task, the scientific community has decided to create an imaginary gas that approximates the behavior of all real gases. In other words, the Ideal Gas is a substance that does not exist. The Kinetic Molecular Theory describes that gas. While the use of the Ideal Gas in describing all real gases means that the descriptions of all real gases will be wrong, the reality is that the descriptions of real gases will be close enough to correct that any errors can be overlooked.

The gas consists of objects with a defined mass and zero volume.
The gas particles travel randomly in straight-line motion where their movement can be described by the fundamental laws of mechanics.
All collisions involving gas particles are elastic; the kinetic energy of the system is conserved even though the kinetic energy among the particles is redistributed.
The gas particles do not interact with each other or the with the walls of any container.
The gas phase system will have an average kinetic energy that is proportional to temperature; the kinetic energy will be distributed among the particles according to a Boltzmann type of distribution.

And if you still don't understand go to :
http://wine1.sb.fsu.edu/chm1045/notes/Gases/Kinetic/Gases08.htm
www.chm.davidson.edu/ChemistryApplets/KineticMolecularTheory/BasicConcepts.html
Hope it will help you!

Answer 3

kinetic theory
n.

A theory concerning the thermodynamic behavior of matter, especially the relationships among pressure, volume, and temperature in gases. It is based on the dependence of temperature on the kinetic energy of the rapidly moving particles of a substance. According to the theory, energy and momentum are conserved in all collisions between particles, and the average behavior of the particles can be deduced by statistical analysis.

Answer 4

you're able to be able to desire to appreciate 2 substantial aspects. [association of debris] a million. gasoline molecules are very far aside. debris are randomly arranged and could occupy any obtainable area. 2. This ends up in gases having very low densities. [flow of debris] a million. debris have little or no charm between them and pass approximately randomly at an rather intense velocity. 2. This explains why gases have not have been given any fastened quantity and shape, and why they're fairly compressible.

Answer 5

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