How does the molecular mass affect diffusion of different substances

Mass of the molecules diffusing: Heavier molecules move more slowly; therefore, they diffuse more slowly. The reverse is true for lighter molecules. Temperature: Higher temperatures increase the energy and therefore the movement of the molecules, increasing the rate of diffusion.

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what is the average time it took the car to travel 0.25 meters?

⇒ 2.23 seconds

what is the average time it took the car to travel 0.50 meters?

⇒ 3.13 seconds