What generally happens to the motion of molecules or atoms when the temperature is decreased from 298 K to 273 K?
By a definition, the temperature is a measure of the average kinetic energy of the molecules or atoms. The velocity of motion is proportional to the square root of kinetic energy. When the temperature is decreased from 298 K to 273 K, it corresponds to removing heat energy. As a result, the average kinetic energy of the molecules decreases, and the molecules or atoms decreases their motion.