Talk:Empirical formula

Can any body please solve this, show all the workings: 81.8 Carbon, 18.2 Hydrogen --Reeba 09:27, 19 July 2007 (UTC)

	This article is within the scope of WikiProject Chemistry, a collaborative effort to improve the coverage of chemistry on Wikipedia. If you would like to participate, please visit the project page, where you can join the discussion and see a list of open tasks.ChemistryWikipedia:WikiProject ChemistryTemplate:WikiProject ChemistryChemistry
???	This article has not yet received a rating on Wikipedia's content assessment scale.
???	This article has not yet received a rating on the project's importance scale.

Physics Unassessed

	Physics portal This article is within the scope of WikiProject Physics, a collaborative effort to improve the coverage of Physics on Wikipedia. If you would like to participate, please visit the project page, where you can join the discussion and see a list of open tasks.PhysicsWikipedia:WikiProject PhysicsTemplate:WikiProject Physicsphysics
???	This article has not yet received a rating on Wikipedia's content assessment scale.
???	This article has not yet received a rating on the project's importance scale.

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.

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)[reply]

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?