Final answer:
The rate of diffusion is affected by the steepness of the concentration gradient, the mass of the molecules, temperature, and the characteristics of the membrane such as its surface area and permeability.
Step-by-step explanation:
The rate of diffusion is dependent upon several factors that can influence how quickly a substance moves from an area of high concentration to an area of lower concentration across a membrane. These factors include the steepness of the concentration gradient, mass of the molecules diffusing, temperature, and the characteristics of the membrane itself such as surface area and permeability.
Specifically, a greater difference in concentration leads to more rapid diffusion, whereas the process slows down as equilibrium is approached. Similarly, lighter molecules tend to diffuse more quickly compared to heavier ones. The temperature also plays a critical role, with higher temperatures typically increasing the rate of diffusion due to the enhanced movement of molecules. Finally, the characteristics of the membrane, such as surface area and permeability to the diffusing molecules, are crucial, with larger surface areas and higher permeability facilitating a higher rate of diffusion.