Final answer:
Increasing the concentration gradient enhances the rate of net diffusion since there is a greater difference in concentration, which serves as the driving force for molecule movement.
Step-by-step explanation:
If you increase the concentration gradient of a substance, the effect on the rate of net diffusion will be an increase. The net rate of diffusion is directly proportional to the extent of the concentration gradient; a higher concentration difference results in a more rapid diffusion process.
As molecules move from an area of higher concentration to an area of lower concentration, raising the concentration gradient enhances the driving force for diffusion, causing a higher rate of molecule movement. However, once equilibrium is reached, the concentration difference disappears, and there will be no net diffusion. Factors such as the mass of the molecules diffusing and temperature can also affect diffusion rates, with lighter molecules and higher temperatures typically increasing the rate of diffusion.