Talk:Mole fraction

Amount fraction

There should definitely be some indication here that a mole fraction is a measure of moles as an "amount" rather than weight. — Preceding unsigned comment added by 124.169.164.82 (talk) 11:08, 15 April 2012 (UTC)

Who's Calls this 'Amount Fraction'...Someone pls show me or give me and explanation of any higher education society that uses the term amount fraction over mole fraction...This is a specific ration of MOLES of a substance. —Preceding unsigned comment added by 204.249.5.200 (talk) 01:18, 23 March 2009 (UTC)

dictionary definition?

I'm a bit confused here. The article appears to me to be a long-winded way of giving a dictionary definition, that the "mole fraction" of a component ("type of molecule") in a mixture is the proportion of molecules in the mixture to belong to it.

Is that correct? If so, can't we say so?

Appealing to moles appears to me to be a bit of a detour - for non-chemists, who are going to use this for theoretical rather than practical purposes, molecules are a more immediate concept. The mole fraction of X in Y is the probability that a molecule of Y, chosen at random, is actually X. The rest is pretty much obvious.

RandomP 10:30, 17 September 2006 (UTC)

It is mole fraction simply because solutions aren't always molecular. For the example given, there is no molecule of NaCl as it is an ionic compound. So we're not appealing to moles, rather the use of the mole is a more accurate usage. Yeah, that may be a bit much for the non-chemist maybe - so what? That said, the whole thing could be simplified and clarified as it is indeed one of the more simple concepts in chemical concentration. Vsmith 14:00, 17 September 2006 (UTC)

Thanks for the clarification! So it's more of a "particle fraction". Just out of curiousity, would a statement like "the mole fraction of hydrogen in water is 2/3" make sense to a chemist, make them wince, or both? (I.e. speaking of the numerical proportion of atoms in molecules rather than atoms/proper molecules/whatever compounds in a real solution)

"numerical proportion of X molecules in a solution Y" still strikes me as better terminology than "mole fraction", but changing chemical terminology is slightly beyond the scope of Wikipedia :-)

(Thanks for the cleanup edit, too!)

RandomP 16:25, 17 September 2006 (UTC)

Makes sense, although not usually stated that way. Chemical formulas are simply mole ratios of the constituent atoms or ions. The subscripts can be used to express a mole fraction. This can get complicated though - consider ammonium phosphate (NH₄)₃PO₄. Consider also alloys such as brass, in which two or more metals can exist in a range of proportions. Although usually expressed in terms of weight or mass percent, they can be described in terms of mole fractions for a particular alloy formulation - no molecules involved. Vsmith 17:04, 17 September 2006 (UTC)

This needs language that is easier to understand for someone taking Gen Chem for the first time, something non-mathematical, or "in plain english." This article plainly has me lost.

User: Komodo9mm: 2044pm, 30 Jan 2007 —The preceding unsigned comment was added by 68.227.171.164 (talk) 02:45, 31 January 2007 (UTC).

moles of substance before being dissolved or dissolved

Can anybody tell me if you take the moles of the solute before or after it has been dissolved? Electrolytes like e.g. NaCl form ions when they dissolve. --173.53.83.10 (talk) 21:29, 12 February 2010 (UTC)

One mole of NaCl makes one mole of Na+ and one mole of Cl- when it ionizes. Gah4 (talk) 15:43, 22 May 2017 (UTC)

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Inhomogeneous or non-uniform mixture

Non-uniform spatial values of mole/mass fraction causes diffusion, so the qualifier (spatially) non-uniform mixture is better phrasing than inhomogeneous mixture which refers to multi-phase mixture(s).--MagnInd (talk) 10:05, 17 July 2012 (UTC)

I don't think that the meaning of inhomogeneous is restricted to multi-phase mixtures. Anyway, if you prefer "spatially non-uniform mixture" instead of "inhomogeneous" that's fine with me.--RolfSander (talk) 10:41, 17 July 2012 (UTC)

Mole and numbers

As far as I can remember Mole wasn't so wide and complex definition. It is simple number of molecules. That is all. Whoever wrote this article, wrote article about reasons for inventing mole in first place, but not mole itself. Marek Artur Penther 86.150.164.79 (talk) 06:04, 11 May 2014 (UTC)

As above, it can also be numbers of atoms or ions or electrons or almost anything else. It is a convenient size for lab work, though mMol might be even more convenient. Chemistry does reaction energy in kCal/Mol, where physics uses eV, leaving out the unit for the particle, as it is one of whatever is being discussed. US chemical engineers use pound-mole, but conveniently the ratio of pound moles is the same as the ratio of the gram-mole, the specific term for what most just call mole. Gah4 (talk) 15:57, 22 May 2017 (UTC)

Mol%

Is Mol% commonly used? I just saw it in an article on plutonium in bombs. As well as I know, it is more usual to use mMol when Mol is too big. I would change that one to mMol, but I thought I should ask here first. Gah4 (talk) 15:18, 9 February 2017 (UTC)