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Kinetic Molecular Theory

The Kinetic Molecular Theory (KMT) explains the behavior of gases based on the motion of particles. It provides a microscopic understanding of gas laws and helps predict how gases respond to changes in temperature, pressure, and volume.

Postulates of Kinetic Molecular Theory​

  1. Gas particles are in constant, random motion.
  2. Gas particles are very small compared to the distance between them; most of the gas volume is empty space.
  3. Collisions between gas particles and container walls are elastic, meaning no kinetic energy is lost.
  4. No intermolecular forces exist between gas particles; they do not attract or repel each other.
  5. Average kinetic energy of gas particles is proportional to temperature in Kelvin.

Implications of KMT​

  • Explains pressure: Gas pressure arises from collisions of particles with container walls.
  • Explains temperature effects: Increasing temperature increases kinetic energy, raising pressure if volume is constant.
  • Supports gas laws: KMT underpins the Ideal Gas Law, Boyle’s Law, Charles’s Law, and others.

Limitations​

  • Does not account for intermolecular forces or finite particle volume, which are important at high pressures and low temperatures.
  • Real gases deviate from ideal behavior under these conditions.

Applications​

  • Predicting gas behavior in chemical reactions and laboratory experiments.
  • Understanding diffusion, effusion, and gas transport phenomena.
  • Forming the basis for statistical mechanics and thermodynamics.

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