Which factor does NOT impact the rate of diffusion?

The rate of diffusion is influenced by several factors that relate to the physical properties of the substances involved and the environment they are in. The concentration gradient, for instance, is a primary driver of diffusion; substances will tend to move from areas of higher concentration to areas of lower concentration until equilibrium is reached. Similarly, the molecular weight of solutes also plays a significant role: lighter molecules tend to diffuse faster than heavier ones. Surface area is crucial as well, since a larger surface area allows for greater interaction between molecules, facilitating a higher rate of diffusion.

Time of day, however, does not inherently affect the diffusion process. While external factors like temperature and pressure might vary throughout the day, which could indirectly influence diffusion, the fundamental principles governing how molecules move across regions are not dependent on the time. Therefore, it is correct to state that time of day is not a direct factor impacting the rate of diffusion.