Chemistry Gases MDCAT 2019
PMDC Verified Question 54 of 65
All the collisions between the particles of gases are elastic in nature. What is meant by "Elastic Collisions"?
A
The velocity of the molecules changes
B
No change in mass during the collisions
C
No change in the kinetic energy (no change in total energy)
D
No change in potential energy during the Collisions
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option C: No change in the kinetic energy (no change in total energy)
Concept:

According to the Kinetic Molecular Theory (KMT) of gases, the collisions between gas molecules, as well as with the walls of the container, are perfectly elastic.

Solution:

  • An elastic collision is fundamentally defined in physics as a collision in which there is no net loss or gain of kinetic energy.


  • When gas particles collide, they may transfer kinetic energy from one to another, but their total kinetic energy remains completely conserved.


Why other options are incorrect:

  • Option A: While velocities of individual molecules do change upon collision, this does not define the term "elastic".
  • Option B: Mass is conserved in all types of collisions (both elastic and inelastic).
  • Option D: Ideal gas molecules are assumed to have no intermolecular forces, and thus no potential energy to begin with.

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