Admission Test for Dental Hygiene (ATDH) Practice

Which of the following concepts is NOT a part of Kinetic Molecular Theory?

1. Particles are in constant motion.

2. Heavier particles move slower than lighter ones.

3. Gas particles are attracted to each other.

4. Temperature affects particle speed.

The correct answer is: Gas particles are attracted to each other.

Kinetic Molecular Theory provides a model for understanding the behavior of gas particles, and it emphasizes several key concepts about these particles and their motions. One of the foundational elements of this theory states that gas particles are in constant motion, which provides a basis for explaining gas pressure and temperature effects. In regard to the specific choice regarding attraction between gas particles, Kinetic Molecular Theory actually assumes that gas particles do not exert significant forces on each other under typical conditions. Instead, the theory posits that gas particles are essentially independent of one another, moving freely and colliding elastically without any appreciable forces acting between them. Therefore, the idea that gas particles are attracted to each other contradicts the assumptions laid out in Kinetic Molecular Theory, making it the correct response since it does not align with the core principles of the theory. The remaining concepts are integral to understanding how gases behave: constant motion describes the inherent behavior of particles in gas, the relationship between particle mass and speed indicates that lighter particles indeed move faster on average than heavier ones, and the influence of temperature on particle speed is a critical factor, as temperature is a measure of the average kinetic energy of particles. Understanding these foundational principles helps to frame the behavior of gases as described by Kinetic Molecular Theory