What is the term for the lowest possible temperature where molecular motion stops?

The term for the lowest possible temperature at which molecular motion stops is known as Absolute Zero. At this theoretical temperature, which is 0 Kelvin or -273.15 degrees Celsius, the kinetic energy of particles is minimized, causing them to reach a state of rest. This means that at Absolute Zero, the thermal motion of atoms and molecules ceases, fundamentally altering their behavior and interactions.

This concept is significant in the fields of physics and chemistry, as it establishes a baseline for temperature measurements and impacts various phenomena, including the behavior of gases and the properties of materials. Understanding Absolute Zero is crucial for scientists studying thermodynamics and quantum mechanics, as it represents a limit that cannot be physically achieved but serves as an essential reference point in theoretical discussions.

The other choices relate to different temperature concepts: the Freezing Point refers to the temperature at which a substance changes from a liquid to a solid, Thermal Equilibrium involves the state where all systems in contact have reached the same temperature, and the Kelvin Scale is a temperature scale used in science that starts from Absolute Zero but does not define the lowest limit itself.