Chemistry Regents Practice Test 2025 – Complete Prep Resource

The temperature of a sample of matter is a measure of the average kinetic energy of its particles. This concept arises from the kinetic molecular theory of matter, which states that the particles in a substance are in constant motion. The faster these particles are moving, the higher their kinetic energy, which in turn correlates to a higher temperature.

When the temperature of a substance increases, it indicates that the average speed of the particles is increasing, resulting in greater kinetic energy. Conversely, if the temperature decreases, the particles are moving more slowly, leading to lower kinetic energy. Therefore, temperature serves as an indicator of the motion and energy state of the particles within a sample of matter.

This concept helps explain why temperature is often used to understand thermal energy transfer, heat capacity, and reactions, as it reflects the energy that can be transferred or transformed during these processes.