Final answer:
Absolute zero is the lowest possible temperature at which all molecular motion ceases. It is represented as -273.15°C or 0 K. The concept arises from the behavior of gases and the pressures of gases extrapolating to zero at the same temperature.
Step-by-step explanation:
Absolute zero is the temperature at which all molecular motion has ceased. It is the lowest possible temperature that can be theoretically achieved. The concept of absolute zero arises from the behavior of gases, where the pressures of gases extrapolate to zero at the same temperature, which is -273.15°C or 0 K.
Absolute zero has never been attained in the laboratory, but temperatures close to it have been achieved. The Kelvin temperature scale is based on molecular motion and absolute zero is also referred to as 0 K.
Example: If the average kinetic energy of particles in a hydrogen sample at 200 K is twice that of a hydrogen sample at 100 K, it means that at absolute zero (0 K), the motion of particles theoretically ceases.