Answer: Sample A
Explanation:
Since the kinetic energy of a gas is proportional to its temperature in kelvin, Kelvin temperature represents its kinetic energy. Despite the fact that individual gas molecules (differently and) represent variable speeds, gas temperature and energy in its kinetic version refer (rather; is on) average speed. The mean kinetic energy of a molecule in gas, on the other hand, is proportional to the temperature. For temperatures higher than those of the boiling point, the movements of the gas molecules tend to be quicker. While, for instance, we were studying differences in the movement of oxygen gas particles at different temperatures, different samples possess the various kinetic energies. Respectively, the sample of the lowest temperature has the maximum molecular speed at their lowest kinetic energy and the slowest mean speed.
Since 250K is the lowest temperature, the particles will be moving at the lowest speed. Remember, Kelvin measures speed of movement as a temperature unit. Therefore, Sample A has the smallest average speed.
