Michigan Test for Teacher Certification (MTTC) Secondary Integrated Science Practice test

Which of the following best describes kinetic molecular theory?

1. It describes the fixed position of molecules in solids

2. It explains the behavior of gases in terms of motion

3. It states that all molecules are always at rest

4. It focuses on the interactions of ionic compounds

The correct answer is: It explains the behavior of gases in terms of motion

Kinetic molecular theory is a fundamental concept in chemistry and physics that explains how gases behave. The theory posits that gas molecules are in constant, random motion and that this motion is responsible for the properties of gases, such as pressure and temperature. According to the kinetic molecular theory, the temperature of a gas is related to the average kinetic energy of its molecules. The more energy they possess, the faster they move, which directly influences their behavior in terms of expansion, compression, and diffusion. In contrast to the other choices, the kinetic molecular theory specifically focuses on the dynamic nature of gases rather than the static arrangement of molecules in solids, the incorrect notion that molecules are always at rest, or the interactions among ionic compounds. Each of those options does not capture the essence of kinetic molecular theory, which is deeply rooted in the motion and energy of particles, particularly in gaseous states.