Talk:Osmotic concentration

Tonicity
Osmolarity and tonicity are not the same thing. thnnbvv Osmolarity pressure that solutes exert on either side of a membrane that allows only water to pass. In contrast, tonicity does not assume such a membrane. Thus, osmolarity is affected only by what solutes are put initially on both sides of the membrane, whereas tonicity is affected by both this and the possible flow of those solutes to the other side, which affects osmosis.

the articles should be linked, but merging them would be confusing.


 * You are absolutely correct that osmolarity and tonicity are not the same thing. However, I believe you otherwise have your definitions for osmolarity and tonicity confused. Tonicity is in fact the phenomenon that refers to water movement exclusively, not osmolarity. Osmolarity takes into account the molecules that can't cross a membrane as well as those that can. I am not entirely sure though whether or not osmolarity absolutely demands the presence of a membrane. The majority of the definitions I've seen refer to the necessity that solutes exert oncotic pressure over a membrane. But it seems to me that simply having particles that would be oncotically active is enough to define a solution's osmolarity without the actual presence of a membrane. IE: A 1mM solution of sodium chloride represents a 2 mOsm/L solution, whether or not a membrane is present. I personally think an "Osmolarity vs. Tonicity" page should be created independent of "Osmolarity" and "Tonicity", to which both pages could link.

Requested move
I'm suggesting moving this page to Osmolarity instead of having that term redirect here. "Osmolarity" is the term/concept you find in the indices of biology textbooks and "osmole" is just the unit it is measured in. After the first sentence, the whole article talks about osmolarity and redirecting it to Osmole (unit) is a bit like redirecting light to Einstein (unit). - tameeria (talk) 15:22, 10 December 2007 (UTC)

Addendum: Alternatively, all these terms (osmolarity, osmolality, osmole) could be merged with/redirected to osmotic pressure. Maybe that would make even more sense than moving this page. - tameeria (talk) 16:56, 11 December 2007 (UTC)


 * I'm not sure osmotic pressure is the best home for it since there is also osmotic potential. I do think that osmole is a little obscure and osmolarity would seem to be a better home. David D. (Talk) 05:06, 13 December 2007 (UTC)


 * I support a move to Osmolarity per David D. --Lox (t,c) 12:11, 17 December 2007 (UTC)


 * ✅ Neıl ☎  14:15, 17 December 2007 (UTC)

Possible error
I believe this is an error, could somebody please correct....

"nju of the erythrocyte"

nju is possibly a typo? —Preceding unsigned comment added by 86.155.149.249 (talk) 12:15, 28 December 2007 (UTC)

Clean up the -osmotic and -tonic section?
I've fixed some minor grammatical mistakes in this section and stuck two separated sentences into one initial paragraph, but the section seems to be a bit disjointed and repetitive. It could probably use some more cleaning up. --Giftiger Wunsch (talk) 18:42, 10 January 2009 (UTC) Bold text

this article is completely incorrect
Osmolarity is mOsmol/L, not Osmol/L. In most chemistry classes and pharmaceutical classes, osmolarity is never referred to as Osmol/L. Please change accordingly. —Preceding unsigned comment added by 24.32.48.86 (talk) 05:19, 20 July 2010 (UTC)

Property and unit mixed up
The equation
 * $$ \mathrm{osmol/L} = \sum_i \varphi_i \, n_i C_i$$

has a unit on left side and a (calculation of a) physical property on right side, so there can not be an equal sign between left and right side. Probably the equation should be:
 * $$ C_{os} = \sum_i \varphi_i \, n_i C_i$$

or
 * $$ \mathrm{Osmolarity} = \sum_i \varphi_i \, n_i C_i$$

Benadikt (talk) 14:15, 31 August 2015 (UTC)
 * You're right. Corrected. Tinss (talk) 03:45, 19 February 2016 (UTC)

There are some confusion in the article “Osmotic Concentration”. According to the equation[3] Osmolarity = Osmolality*(ρsol-ca) = Osmolality*(water g/solution ml +solute g/ solution ml－Ca) = Osmolality*[the mass density of water *( water ml/ solution ml)] IUPAC states that Osmotic Concentration is the ”production of the Osmolality and the ass density of water. Formerly called Osmolarity”. As water ml does NOT strictly equal solution ml, the above derivation shows that “osmotic concentration”and “Osmolarity” are not equivalent. In another word, osmotic concentration is NOT a synonym of Osmolarity. I'd also suggest another symbol to be used for “osmotic concentration” in IUPAC Goldbook

References goldbook version2.3.3 2014-02-24 p.1044 Shihuimin (talk) 04:19, 23 June 2016 (UTC)

Merging Osmole (unit) into this article
I propose that Osmole (unit) should be merged into this article. It is currently a stub with no references, whose content almost exactly matches the "Types of solutes" section of this page, aside from some uncited pieces of anatomy trivia. A brief "unit" section can be created in this article to contain any useful information Osmole (unit) has. --HighFlyingFish (talk) 03:06, 8 October 2017 (UTC)
 * Since no one objected over several months, I have performed the merger. --HighFlyingFish (talk) 06:38, 19 January 2018 (UTC)

osmolality is an expression of solute osmotic concentration per mass of solvent, whereas osmolarity is per volume of solution
better to use osmolamity for mass and osmolavity for volume — Preceding unsigned comment added by 82.140.130.86 (talk) 09:49, 24 January 2019 (UTC)