Talk:Empirical formula

Untitled
The definition given suggests that C3H7 is also a valid empirical formula for hexane, but I'm not sure if this is a flaw in the definition or not. Noser 19:29, 8 Dec 2004 (UTC)


 * You are correct - it was a flaw in the example. Fixed it. -Vsmith 03:44, 10 Dec 2004 (UTC)

Valence exchange technique
I removed the following two paragraphs from the article.And let me inform you that chemistry labs are terrible


 * To calculate the empirical formula for two elements (excluding transition metals, lanthanides and actinides), switch the valency of the two elements involved. For example, equation for water is H2O. The valency of H (hydrogen) is 1, and the valency of O (oxygen) is 2. Switch the valencies and you get H2O.


 * N.B. This only works for TWO elements.

The proposed calculation technique lists four exceptions: three large groups of elements, and any compound with more than two elements. But in this very article, the example of hexane contains only two elements, neither of which is in the listed exceptional groups, but hexane's empirical formula is C3H7, not CH4 as predicted by the technique

This makes me think that the technique is simply not worth the trouble. If any editor feels strongly about it, feel free to put it back, but please list all the exceptions (explaining why it fails for hexane, hydrazine, and hydrogen peroxide, for instance). Also include a reference to a reputable source which explains the technique and the reason it works. ACW 20:50, 11 June 2006 (UTC)

Chemical v Molecular v Empirical Formula
The article on Empirical Formula equates "chemical formula" with "empirical formula," and distinguishes "molecular formula"

The article on Chemical Formula equates "chemical formula" with "molecular formula" and distinguishes "empirical formula"

(There is no separate article on "Molecular Formula")

So who is right?

There are many types of chemical formula. An empirical formula and a molecular formula are both types of chemical formula. So to say chemical formula is specify an empirical formula or that a chemical formula is specify a molecular formula are both wrong. Jasoninkid (talk) 18:18, 26 January 2019 (UTC)

arxiv.org link
Should probably be changed to external link section??Mikejens (talk) 15:21, 12 November 2008 (UTC)

Should probably be deleted, it is of very limited interest. —Preceding unsigned comment added by 88.3.201.86 (talk) 17:35, 20 December 2008 (UTC)

Moved into external link section. It's not worthy of being in the content, however I thought that someone may find it useful. 58.7.8.182 (talk) 14:03, 29 April 2010 (UTC)

Old question
Can any body please solve this, show all the workings: 81.8 Carbon, 18.2 Hydrogen --Reeba 09:27, 19 July 2007 (UTC) 81.8*12=981.6/36.4=27 18.2*1=18.2*2=36.4/36.4=1 c=27 h=1

Section "Use in physics"
This section needs to be moved to an article of its own, as the introduction refers only to the meaning in chemistry. Alas, many authors have applied changes to this part, so one needs a tool to extract all of them from the history to make the transplant conform to the license. --Mopskatze (talk) 12:04, 2 July 2011 (UTC)

German (Hungarian) terminology
Locus:

"The empirical formula is used as standard for most ionic compounds, such as CaCl2, and for macromolecules, such as SiO2."

Maybe a slight supplement can make the text more congruent with German (Hungarian) terminology (the proposed addition is at the end of the quoted sentence):

"The empirical formula is used as standard for most ionic compounds, such as CaCl2, and for macromolecules (including inorganic "giant molecules", covalent crystals like SiO2: crystals forming a single giant covalent network, a covalent lattice)."

Sorry for my bad English. Sorry also if the terminology "covalent lattice" or "covalent crystal" is not used in English, or would prove to be inconsistent with the article's treatment. Any way, at least in Hungary, and probably also in Germany, it is the standard term for materials like diamond, graphite and quartz. (German equivalent can bee seen here.) "Macromolecule" is rarely used here for covalent crystals (at least in secondary education), although it is sometimes mentioned that they can be regarded as such.

Physis (talk) 14:58, 16 July 2011 (UTC)

Now I found the corresponding articles on English Wikipedia:

Bonding in solids:
 * Ionic solid
 * Molecular solid
 * Network solid (...)
 * Metallic solid

As for network solid, it seems to be mentioned also as covalent lattice or also as covalent crystal.

The corresponding link included now to the variant:

"The empirical formula is used as standard for most ionic compounds, such as CaCl2, and for macromolecules (including inorganic "giant molecules", covalent crystals like SiO2: crystals forming a single giant covalent network, a covalent lattice)."

Physis (talk) 15:13, 16 July 2011 (UTC)

Forgotten subjects
I would argue that empirical formulas also include all formulas that "uses math without being a part of mathematics as such", and which are build upon empiric knowlidge. Formulas that cannot be verified, but are known through expierience. Some very good examples exists within mechanical engeneering. Such as for solid mechanics (or strength mechanics - like pressure, buckling, bending or comination of these), further also for mechanical elements such as gear-wheel-connections, tolerances, bearings and aerodynamics. And not only within construction, there are formulas for production aswell. Like how often shall a certain lathe steel be replaced, if you want a certain quality. Etc. Also within engeneering of buildings lots of empiric formulas are used. Boeing720 (talk) 22:54, 2 March 2014 (UTC)
 * That's covered by Empirical relationship, but maybe the hatnote pointing there should be improved. &mdash;&thinsp; H HHIPPO  21:47, 18 May 2014 (UTC)