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Kinetic-Molecular Theory

Properties of gas molecules

Atoms Practice
Estimated5 minsto complete
Practice Kinetic-Molecular Theory
Estimated5 minsto complete
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Credit: Amy Thibodeau
License: CC BY-NC 3.0

The Hammer and Sickle [Figure1]

Kinetic Molecular Theory

Sometimes things seem to work in theory, but never do in practice. For instance, many countries have tried to create a utopia, usually through Communism, but all have failed. However the strength of the goals and theory behind communism lead it to become a strong model for many governments. Kinetic Molecular Theory is similar to this, as many of the tenants don’t hold in the real world, however it is a good place to start understanding how gases behave.

Review of the 5 postulates of KMT:

1.    A gas consists of a collection of small particles traveling in straight-line motion and obeying Newton's Laws.

2.    The molecules in a gas occupy no volume (that is, they are points).

3.    Collisions between molecules are perfectly elastic (that is, no energy is gained or lost during the collision).

4.    There are no attractive or repulsive forces between the molecules.

5.    The average kinetic energy of a molecule is directly related to its temperature.

Creative Applications

1. Which of these don’t apply for real gases? Why not?

2. When do real gases differ from the KMT?

3. How does the KMT explain Boyle’s Law (that Pressure and Volume are indirectly related)?

4. How does the KMT explain Charles’ Law (that volume is directly related to temperature)?

Further Reading


Image Attributions

  1. [1]^ Credit: Amy Thibodeau; License: CC BY-NC 3.0

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