Why does the kinetic theory of gases neglect potential energy ?

In summary, in a gas, the forces between atoms are very weak due to the large spaces between them. This means that the force is not inversely proportional to the square of the distance, as it drops even quicker with increasing distance. This also explains why the potential energy is negligible as the potential at infinity and at real distances are nearly the same.
  • #1
kira506
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My textbook says that the forces of intermolecular attraction between gas molecules are very weak due to large intermolecular spaces between them , that's why they're negligible , Does this have a relation with "force is inversely proportional to the square of distance " (again , I don't know if this rule even applies here !) and my textbook also says that due to that , the potential energy is = Zero , what does that have to do with weak intermolecular forces that are negligible ?
 
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  • #2
Forces between atoms in a gas usually do not follow an inverse square law - they drop even quicker with increasing distance.

If forces are negligible, the potential "at infinity" and the potential at real distances is nearly the same, therefore the potential energy (defined as this difference) is negligible.
 
  • #3
mfb said:
Forces between atoms in a gas usually do not follow an inverse square law - they drop even quicker with increasing distance.

If forces are negligible, the potential "at infinity" and the potential at real distances is nearly the same, therefore the potential energy (defined as this difference) is negligible.

Thank you ! This was really helpful :smile:
 

1. Why is potential energy neglected in the kinetic theory of gases?

The kinetic theory of gases is based on the assumption that gas particles are in constant motion and have negligible volume. This means that they do not interact with each other or with their surroundings, and therefore, potential energy is not considered as it does not affect the particles' motion.

2. Can potential energy be completely ignored in the kinetic theory of gases?

No, potential energy cannot be completely ignored as it is still present in the system. However, it is much smaller in magnitude compared to the kinetic energy of the gas particles, and thus, it is often neglected in calculations for simplicity.

3. What is the main focus of the kinetic theory of gases?

The main focus of the kinetic theory of gases is to understand and explain the behavior of gases in terms of the motion of their particles. It is particularly useful in explaining gas pressure, temperature, and volume.

4. Is the kinetic theory of gases applicable to all gases?

The kinetic theory of gases is applicable to all gases, regardless of their chemical composition. This is because it is based on the fundamental properties of gas particles such as mass, velocity, and energy, which are independent of the type of gas.

5. How does the neglect of potential energy affect the accuracy of the kinetic theory of gases?

The neglect of potential energy does not significantly affect the accuracy of the kinetic theory of gases for most practical applications. However, it may lead to slight deviations in certain situations, such as at high pressures or low temperatures, where intermolecular forces become more significant.

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