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Kinetic theory (mean KE) Calculator

Relate mean kinetic energy to temperature.

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Mean KE

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Overview

This fundamental equation of kinetic theory establishes a direct relationship between the microscopic translational kinetic energy of gas molecules and the macroscopic measure of absolute temperature. It shows that temperature is a manifestation of the average energy of motion possessed by the particles in a system.

Symbols

Variables

k = Boltzmann Constant, T = Temperature, = Mean KE

Boltzmann Constant
J/K
Temperature
Mean KE

Apply it well

When To Use

When to use: Apply this equation when calculating the average energy of a single particle in an ideal gas sample. It is used under the assumptions of the kinetic-molecular theory, where particles are in constant random motion and intermolecular forces are neglected.

Why it matters: It provides the physical definition of temperature, explaining why heating a substance increases the speed of its constituent atoms. This principle is vital for understanding heat transfer, thermodynamics, and the behavior of atmospheres and plasmas.

Avoid these traps

Common Mistakes

  • Using Celsius for T.
  • Confusing k with R.

One free problem

Practice Problem

Calculate the mean translational kinetic energy of a gas molecule at a room temperature of 293 K.

Boltzmann Constant1.38e-23 J/K
Temperature293 K

Solve for: Ek

Hint: Plug the temperature directly into the formula, ensuring the Boltzmann constant is in J/K.

The full worked solution stays in the interactive walkthrough.

References

Sources

  1. Atkins' Physical Chemistry
  2. Halliday, Resnick, Walker - Fundamentals of Physics
  3. Wikipedia: Kinetic theory of gases
  4. Wikipedia: Boltzmann constant
  5. NIST CODATA
  6. Fundamentals of Physics by Halliday, Resnick, and Walker
  7. Thermodynamics and an Introduction to Thermostatistics by Herbert B. Callen
  8. Transport Phenomena by Bird, Stewart, and Lightfoot