Talk:Precipitation (chemistry)

Untitled

This isn't very good, and reads like it has been written by a grade schooler. (anon user)

Your opinion is noted, though you have provided no details of what is wrong with the article. If you feel it needs improvement and you have some knowledge of the topic, feel free to make some changes. if the changes are major, please seek consensus for them on this page first. Euryalus 23:19, 6 May 2007 (UTC)

Why chemical reaction

From your link for definition

Precipitate or the deposit is an insoluble solid formed by reactions in a solution.

Precipitation is also the deposit as result of changing solubility of soluble elements in solid solvent. So chemical reaction is not neccessay. For example carbon can precipitate in steel as pure graphite (theoretically).

Where Does this come from

"After evaporation, condensation occurs and will slowly turn into a cloud." - This is at the end of the main part of the article and it doesn't make any sense to me. I suggest a deletion. Abcjared 06:27, 23 September 2007 (UTC)

Liquid to solid only???

I'm not a scientist or anything, but isn't rain also considered precipitation? That's a phase change from gas to liquid, sort of, not liquid to solid. Is this article lacking? I know that tiny water droplets (liquid phase) becoming snow or sleet or hail (solid phase) is precipitation and is thus relevent to the article, but what about rain? I guess water vapor becoming clouds (gas phase becoming liquid phase) isn't considered precipitation, but what about rain? Sorry if I repeat myself. :) [email protected] 5:01, 28 August 2008 (PST)

Maybe you're looking for Precipitation_(meteorology)? --Rifleman 82 (talk) 17:18, 28 August 2008 (UTC)

How about the reaction NH₃ (g) HCl (g) --> NH₄Cl (s) ?

Ewen (talk) 06:06, 14 October 2008 (UTC)

I would suggest that precipitation is the formation of a heavier insoluble pase as a chemical reaction product or as the result of condensation (phase transisition) due to super saturation. Any views? --Johnsarelli (talk) 15:03, 5 January 2009 (UTC)

Classical precipitation theory (with nucleation and growth subcomponents) has been used to characterize virtually all elementary phase combinations, i.e. the formation of solid, liquid, vapor and even vacancy clusters inside solids, liquids and gases. One possible reference to check on this is Sethna's freely available e-text. Hope that helps a bit. Thermochap (talk) 15:12, 5 January 2009 (UTC)

"Supernatant" redirects to this page, but is not mentioned.

Perhaps it should be explicitly stated that "supernate" is synonymous with "supernatant". —Preceding unsigned comment added by 136.186.1.188 (talk) 00:17, 15 October 2008 (UTC)

I had always assumed that "supernate" was a mispronounciation and corruption of "supernatant". Is it a real word? I cannot find "supernate" in the dictionary. 152.5.254.22 (talk) 19:27, 4 January 2013 (UTC)

Primery and secondary

Hello, Is it possible to elaborate more on primery vs. secondary precipitation?
For example, in relation to crystal growth.
Thanks, Omer. http://sites.google.com/site/omermar/ 07:34, 27 May 2009 (UTC)
—Preceding unsigned comment added by Omermar (talk • contribs)

precipitant

Although I am not familiar with precipitation, a document I am looking at seems to indicate that the substance used to cause precipitation is called a "precipitant," "precipitating agent," or the like. 67.101.6.76 (talk) 05:59, 7 January 2011 (UTC)

Representation using chemical equations

What about the very common practice, often encountered in textbooks, of representing the precipitation of solids out of the liquid pase with a downwards-pointing arrow (↓)? --Tomásdearg92 (talk) 13:58, 4 December 2011 (UTC)

Assessment comment

The comment(s) below were originally left at Talk:Precipitation (chemistry)/Comments, and are posted here for posterity. Following several discussions in past years, these subpages are now deprecated. The comments may be irrelevant or outdated; if so, please feel free to remove this section.

It states that a precipitate is the result of a reaction, and is indicative of chemical change having taken place. However precipitates can be formed via alternate routes as well, such as dissolution in hot liquid followed by cooling.

Last edited at 14:24, 10 August 2007 (UTC). Substituted at 03:21, 30 April 2016 (UTC)

Precipitation upon addition of organic solvent

This article could be easily expanded by the addition of a section that talks about how precipitation is sometimes induced by the addition of an organic solvent. For example, adding an equal volume of methanol to seawater will cause the salt in the water to precipitate out. There's an interesting paper here that mentions in its abstract that "all chemists are very familiar with the notion that adding an organic solvent to an aqueous solution induces the rapid precipitation of dissolved inorganic salts". Daemyth (talk) 23:29, 7 November 2016 (UTC)

Examples of chemical reaction

There should be examples Daksh777 (talk) 07:04, 6 February 2019 (UTC)

I removed this

Without sufficient force of gravity (settling) to bring the solid particles together, the precipitate remains in suspension. After sedimentation, especially when using a centrifuge to press it into a compact mass, the precipitate may be referred to as a 'pellet'. Precipitation can be used as a medium. The precipitate-free liquid remaining above the solid is called the 'supernate' or 'supernatant'. Powders derived from precipitation have also historically been known as 'flowers'. When the solid appears in the form of cellulose fibers which have been through chemical processing, the process is often referred to as regeneration. Huzaifa abedeen (talk) 09:57, 28 November 2020 (UTC)

Multiple topics and unfocused content

I have tried to restructure somewhat the outline of this page in a more consistent way in order to address the mentioned issues (multiple topics and unfocused content), i.e., by reordering informations according to:

• Inorganic chemistry
  • Aqueous solutions
  • Metallurgy and alloys
• Organic chemistry
• Biochemistry
• Industrial uses
• Other uses

More copy edit of the page is still needed. Feel free to still improve the page and to remove the tag when it will have attained a sufficient quality. Shinkolobwe (talk) 21:08, 5 May 2021 (UTC)