From Citizendium
Jump to navigation Jump to search
This article is developing and not approved.
Main Article
Related Articles  [?]
Bibliography  [?]
External Links  [?]
Citable Version  [?]
To learn how to update the categories for this article, see here. To update categories, edit the metadata template.
 Definition In science, engineering and in general common usage: the measure of how much of a given substance there is in a given mixture of substances. [d] [e]
Checklist and Archives
 Workgroup categories Engineering, Chemistry and Physics [Categories OK]
 Subgroup categories:  Chemical Engineering and Environmental Engineering
 Talk Archive none  English language variant American English

Many other expressions of concentration

Daniel, as you know, there are quite a few ways to express concentration other than moles per litre. For example:

  • mass per volume (mg/m³, kg/m³, pounds per gallon or lb/gal)
  • parts per million by volume (ppmv) and parts per million by weight (ppmw)
  • molality of solutions, which is moles per mass (mole/kg)
  • mole fraction (moles of component x per total moles)
  • percent by volume (%v) and percent by weight (%w)

Would it not be helpful to mention at least a few of the other ways of expressing concentration? Regards, Milton Beychok 20:06, 29 January 2009 (UTC)

I stick to SI units as far as possible but sure, go ahead. I do not have particular plans for this one, just needed it for Concentration (disambiguation). --Daniel Mietchen 03:38, 1 February 2009 (UTC)

Wikipedia has an article with the same name

I was a minor contributor to the WP article. I have completely re-written, re-formatted and expanded the WP article before uploading it here into CZ. Milton Beychok 01:45, 4 February 2009 (UTC)

I think you're wrong about "general common usage"

When you write in the lede: "in general common usage, concentration is" so-and-so, I won't dispute that a fairly common usage is something like "the concentration of orange juice concentrate to water is one to three" or whatever.

A more common usage, I would submit, is "Pancho Gonzales displayed other-worldly powers of concentration as he came back from two sets down to...."

"Concentration" (and "focus") are such cliches these days that one can hardly listen to a sporting event without being battered by them on a once-a-minute basis, or so it seems to me. Hayford Peirce 01:54, 4 February 2009 (UTC)

Would you like me to change the wording to read "... and in fairly common usage ..."? Please let me know and I will do so. Its no big deal. However, I must say that what is "general common usage" depends on one's interests. Yes, "concentration" and "focus" are used quite a bit in sports reporting and commentating ... and "concentration" as used in science, engineering, technolgy and many industries is also used quite a bit (perhaps, even more so). So, I guess it depends on what turns you on.
Again, just let me know and I will change the wording. I would like to know what you think of the Concentration article as a whole. I am finding, as a I use Google to search Citizendium that a great many of our existing articles have links to Concentration as used in science, engineering and etc. And I am only partially through my Google search. Milton Beychok 02:43, 4 February 2009 (UTC)
"fairly" would be fine; there might also be some way of tweaking it to something like "and in one fairly common usage." I'll take another look at it tomorrow -- inspiration may come overnight.... As for the article as a whole, I am overwhelmed by all the expertise in it and all the info. Wow! Are you going to expand each of the headings, or is it pretty much in finished form? Hayford Peirce 03:14, 4 February 2009 (UTC)
I'll change the opening sentence to "fairly" for now and await your possible further inspiration. Do I plan to expand each of the headings? Not at the moment. The article now has everything I know on the subject. I will create the "Related Articles" and "Bibliography" subpages as soon as I can. As for upgrading the status from 2 to 1, I will wait 2-3 weeks to see if anyone comes up with any needed revisions or additions.
The monthly Write-a-Thon is tommorrow. Do you think you could get Aleta to credit this article as part of tomorrow's Write-a-thon even though I uploaded a6-7 hours ahead of time? (:>) Regards, Milton Beychok 03:42, 4 February 2009 (UTC)
I would think so -- the rules seem to be fairly informal, or at least a little bit stetchable from time to time.... Hayford Peirce 03:53, 4 February 2009 (UTC)
You're in! Chris Day 04:23, 4 February 2009 (UTC)
Hayford, perhaps one could cover both usages with a Jeff Foxworthy skit, about finding a not terribly bright man, apparently frozen much as the foods he was examining in the frozen food case. When he was able to speak, he explained he was merely following the directions on the orange juice container: "concentrate." Howard C. Berkowitz 20:30, 2 February 2010 (UTC)

This one sentence article should be merged into Concentration

There is really no reason now to have this one-sentence Concentration (chemistry) article, when that one sentence is actually covered in the much larger and extensive Concentration article.

The one sentence in this article is:

In chemistry, concentration indicates what amount of a substance (measured in units of mole) is present in a given volume of reference (usually measured in units of litres or cubic metres).

The Molarity section, one of the many sections in the Concentration article, states:

Molarity or molar concentration (in units of mol/L) denotes the number of moles of a given solute per litre of solution. The units of mol/L are commonly replaced by the symbol M.
The National Institute of Standards and Technology (NIST) of the United States considers the term molarity and the symbol M to be obsolete and recommends using the term amount-of-substance concentration of B (or concentration of B) and the symbol c with SI units of mol/m3 or other SI acceptable units.[1]. This recommendation has not been universally implemented in academia or chemistry research yet.

Note that Molarity in the Concentration (chemistry) is expressed in the same mol/liter as is defined in this one sentence Concentration (chemistry) article.

If there is no objection forthcoming in the next few days, I will merge this article into Concentration and I will add a new section on Mol per volume so that the merged article will then cover that concentration expression as well. Milton Beychok 05:53, 9 May 2009 (UTC)

Since there have been no objections to the proposed merge, I have made the merge. Milton Beychok 17:38, 13 May 2009 (UTC)

Edit needed, I believe

Milton, under, you direct the reader, for more information, to Concentration (chemistry), but clicking there redirects to this article. Anthony.Sebastian 04:47, 20 January 2010 (UTC)

Anthony, thanks for picking that up. There was once a 1-sentence article at "Concentration (chemistry)" that was merged into this article. So I am simply going to remove the link to "Concentration (chemistry)" from this article. Milton Beychok 05:17, 20 January 2010 (UTC)

Merged talk histories

I just merged the talk histories here from 'concentration' and 'concentration (chemistry)'. Chris Day 17:34, 2 February 2010 (UTC)

  1. NIST Guide to SI Units NIST website, accessed February 1, 2009. (Scroll down to item 18)