Final answer:
According to the kinetic-molecular theory of gases, gases have the same average kinetic energy at a given temperature. This means that the kinetic energy of gas particles is directly proportional to the temperature of the gas. Gases composed of lighter molecules have more high-speed particles, while gases consisting of heavier molecules have more low-speed particles.
Step-by-step explanation:
According to the kinetic-molecular theory of gases, the average kinetic energy of gas particles is directly proportional to the temperature of the gas. This means that at a given temperature, all gases will have the same average kinetic energy. The kinetic energy of gas particles is related to their speed, so gases composed of lighter molecules will have more high-speed particles, while gases consisting of heavier molecules will have more low-speed particles.