speed of osmosis?

[newbie46]

hello, i was learning about osmosis in school and i have a question about it. does the size of the solutes dissolved in water affect the rate of osmosis? kind of a funky question but i just wanna know thanks!

[JackBean]

you mean if you compare e.g. Na+ and say heme? Yes.

[newbie46]

thanks for your quick response. but would larger solutes cause osmosis to happen more quickly or slowly than smaller solutes? also, if you could please elaborate on why ? thank you!

[JackBean]

what do you think?

[newbie46]

well, if i were to guess, i would have to say that a larger solute would take less energy since it would be less liable to slip through the membrane. in class we barely went over the topic of osmosis so i'm not exactly sure of what a large solute like sugar would do vs a small solute like sodium.

[JackBean]

less energy? What do you mean by that?

[newbie46]

well, i guess i was thinking of reverse osmosis when i said energy

im still not exactly sure of how or why the size of the solute would or wouldnt affect the rate. is there something i failed to research correctly, since none of my research has given me any results

[JackBean]

Just imagine some large net with relatively large holes in it. Cat will go through it easily, right? You will have probably some problems, but may be able to pass. Elephant would have no chance to get through, unless it breaks it

[jonmoulton]

This might help -- smaller molecules diffuse faster than larger molecules. Think about the relationship of diffusion and osmosis. In addition to diffusion, membrane permeability is a factor -- that's Jack's cats and elephants metaphor. The combination of diffusion rate and membrane permeability determines the rate of osmosis. Other factors, such as temperature and viscosity, will also affect the rate. What others did I miss?