/sci/ - Science & Math

(made my own thread but trying to delete because it belongs here)

According to my Biochemistry textbook, osmolarity is determined only by the number of solutes and the size has nothing to do with it.

While I accept this as true because I'm just an undergraduate, no explanation is made and no references are made in the text as to why this happens. Intuitively, one would think that 100 Na+ ions dissolved in a solution with a semipermeable membrane would have less of an effect than 100 large sugars, just in the sense that there would be less water and more solute inside.

Is there an intuitive explanation why molecules being separate is the defining factor of osmolarity? Thanks

According to my Biochemistry textbook, osmolarity is determined only by the number of solutes and the size has nothing to do with it.

While I accept this as true because I'm just an undergraduate, no explanation is made and no references are made in the text as to why this happens. Intuitively, one would think that 100 Na+ ions dissolved in a solution with a semipermeable membrane would have less of an effect than 100 large sugars, just in the sense that there would be less water and more solute inside.

Is there an intuitive explanation why molecules being separate is the defining factor of osmolarity? Thanks