Chemistry Gases SZABMU 2022
PMDC Verified Question 36 of 65
Collision shown by gases involve the following:
A
No energy change
B
No pressure change
C
Small energy change
D
Large energy change
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option A: No energy change
Concept:

According to the Kinetic Molecular Theory (KMT) of ideal gases, all molecular collisions are perfectly elastic.

Solution:

  • An elastic collision is defined as a collision where the total kinetic energy of the system is completely conserved before and after the impact.


  • While individual molecules may transfer kinetic energy to one another (one speeds up, the other slows down), there is zero net loss or gain of energy in the system as a whole.


  • Therefore, the collisions involve "No energy change" in terms of the total macroscopic kinetic energy.


Why other options are incorrect:

  • Options C & D: Any net change (small or large) would imply an inelastic collision, which violates the KMT and would cause the gas to eventually freeze or spontaneously heat up.
  • Option B: Pressure is actually created by these collisions with the walls, so saying "no pressure change" misrepresents the nature of the collision's effect on the container.

Quality & Fidelity Assurance: Every question on BeambePrep is rigorously curated against the official PMDC syllabus with zero filler, zero out-of-syllabus content, and zero typos. When an authentic past paper originally contained a historical mistake or ambiguity from the examining board (such as UHS or NUMS), BeambePrep faithfully reflects the original paper while detailing the nuance and scientific consensus in the autopsy above.

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