Talk:Apparent molar property

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Definition a bit thin[edit]

Opening sentence: "An apparent molar property is a quantity that can be used to calculate a property of a solution." This isn't a definition, and it's pretty vague on top of that. (talk) 12:20, 3 June 2014 (UTC)

I edited this and some other things. The article is still pretty fluffy and watery. (talk) 12:54, 3 June 2014 (UTC)

I have now replaced the opening sentence by a more precise and informative version. Dirac66 (talk) 01:10, 14 March 2016 (UTC)

Ternary mixtures - pseudo-component and pseudo-binary mixtures[edit]

I think it would be a useful addition to article to present the connection between the concept from this article and the pseudo-component defined by process simulation software when analyzing multicomponent mixtures.-- (talk) 12:23, 28 January 2016 (UTC)

Pseudobinary systems can occur in solutions with more than one solvent where the molality can be defined as amount of solute in moles per kilogram of mixed solvent.-- (talk) 23:02, 3 October 2016 (UTC)

Removal of info from article[edit]

I notice an insufficiently explained removal of some subsections from article. Please discuss before removing some details from article.-- (talk) 12:26, 28 January 2016 (UTC)

Yes, some of the deletions seem more justified than others. Perhaps if no further reasons for deletion are given, the rest of us can feel free to restore that content which seems justified. Possibly in improved or modified form. See for example my comment below. Dirac66 (talk) 00:14, 30 January 2016 (UTC)

Solvent apparent quantities[edit]

I see the sections above and the latest edits to article. They seem to assume that the solvent is not entitled to have apparent quantities defined for it. This is a problematic assumption. Thoughts?-- (talk) 07:20, 29 January 2016 (UTC)

Yes, the mention of solvent apparent molar volume was deleted 1-2 days ago by Eric Kvaalen. I have found one thermodynamics textbook (Rock, Peter A., Chemical Thermodynamics, MacMillan 1969, p.227-230) which includes a graph and table of apparent molar volumes of both components of the two-liquid systems water-glycerol and water-ethanol, but without identifying the components as solvent and solute. Probably this is the way to go since there is no rigorous way to define which is solvent and which is solute. Dirac66 (talk) 00:14, 30 January 2016 (UTC)
I see that ref you mention is cited by Handbook of Aqueous Electrolyte Thermodynamics [1].-- (talk) 11:25, 11 March 2016 (UTC)
I have reread the relevant section of Rock's book (and added the missing page numbers above). The graph and table cited are rather confusing to understand. A clearer mention of the properties of both components is at the bottom of p.229, where he uses the data to calculate the values of apparent molar volume for both water and ethanol in the binary mixture at 50 weight per cent ethanol. Dirac66 (talk) 20:06, 12 March 2016 (UTC)
And for another recent reference see Table 4 of this recent paper with detailed data tables for the diethylsulfoxide - methanol system, and also for diethylsulfoxide - ethanol. Dirac66 (talk) 20:20, 12 March 2016 (UTC)
I have now added both the above references to the article, so it is clear that yes, one can measure partial molar volumes for both components of the same system. Dirac66 (talk) 01:10, 14 March 2016 (UTC)
If both components are considered for apparent quantities, is this consideration limited only to mixture of liquids or it can be applied also to liquid-solid (solute) solutions?-- (talk) 11:40, 14 March 2016 (UTC)
My tentative answer is in the footnote I added: For mixtures of a liquid and a solid, the liquid is usually identified as the solvent and the solid as the solute, but the theory is still valid if the labels are reversed. I think the problem with considering the solid as solvent is that its phase change is ignored. Consider for example aqueous NaCl solution at 25oC. Since liquid NaCl does not exist at this T, the only way to find an apparent molar volume of water would be to compare the solution volume with the volume of solid NaCl at the same T. Does this really make sense for a liquid solution? I would like to know what a reliable reference says. Dirac66 (talk) 22:38, 14 March 2016 (UTC)
It seems that phase change is implicitly included when it comes to dissolution. For an ideal solution obtained by dissolving a non-electrolyte solid or gas in a liquid the enthalpy of dissolution equals the enthalpy of fusion.-- (talk) 10:47, 18 March 2016 (UTC)
An opposite aspect involves the solidification of the solution when the liquid freezes and may form a solid solution with the solid solute if they are (partially) miscible in solid state.-- (talk) 10:57, 18 March 2016 (UTC)

Multicomponent systems[edit]

In this context of present discussion, what is the situation of apparent quantities when a solid say an electrolyte is dissolved in a mixture of the two liquids like water and ethanol? Is such a case and even more complex ones presented in the source you mention?-- (talk) 10:37, 2 February 2016 (UTC)
In such cases where there is no rigorous way to define which is solvent and which is solute apparent properties can be ascribed to every component.-- (talk) 12:09, 29 February 2016 (UTC)
Now we have changed the subject to three-component systems: electrolyte, water and ethanol all mixed together. So as indicated in the section Apparent molar property#Multicomponent mixtures/solutions, there is no unambiguous definition of apparent molar properties. Dirac66 (talk) 20:20, 12 March 2016 (UTC)
I don't quite understand which is the nature of ambiguity of the ambiguity since as mentioned above every component can have an apparent quantity defined for it and the number of equations equals the number of components of multicomponent mixtures.-- (talk) 11:40, 14 March 2016 (UTC)
Or perhaps the supposed ambiguity refers to the possibility of treating multicomponent mixtures as if they were (pseudo-)binary ones when the pure component quantity of a component subtracted from the the quantity of the mixture gives the apparent quantity of the other 2 or generally n-1 components from the multicomponent mixture (like above):-- (talk) 11:48, 14 March 2016 (UTC)
?-- (talk) 12:08, 14 March 2016 (UTC)
I do not understand these equations because I don't know what is meant by It is the apparent volume of components 2 and 3 combined, but how exactly do we divide it into the separate effects of components 2 and 3? Actually I can think of more than one possible way, but I have no idea what is actually done in the solution thermodynamics literature. Again we need some reliable sources. Dirac66 (talk) 22:38, 14 March 2016 (UTC)
The possibilities can be enumerated but the division of the apparent quantities of more than one component could be unnecessary at some point (or perhaps could be done by finding the relation between and ). Two or more components from a multicomponent solution can be grouped together (as if they were) (a)s single component. It seems that this is done (at least) for freezing-point depression of more than one electrolyte in a single solvent. Of course sources could be helpful.-- (talk) 11:25, 18 March 2016 (UTC)

I see the most recent edits to article involving a recently noticed source. In these conditions I think that at least some if not all of the content removed in 28th of January this year could be reinserted back with necessary adjustments if needed.-- (talk) 15:40, 18 July 2016 (UTC)

The problem was that the content removed was unsourced, as is some of the content retained. If you can find sources for some of the removed content, go ahead and restore it. Dirac66 (talk) 00:07, 19 July 2016 (UTC)

I also think that the source recently linked on talk:Activity coefficient#Ternary_solutions_-_electrolyte_-_non-electrolyte_interaction regarding sugar salt solutions could be cited as well.-- (talk) 15:45, 18 July 2016 (UTC)

This reference from Food Science may be useful as a source. Perhaps you would like to read it over and see if you can find some material of interest for the article. How does it treat ternary solutions? Dirac66 (talk) 00:07, 19 July 2016 (UTC)

Relation to activity coefficient of an electrolyte[edit]

It seems that there are some relations between an apparent quantity such as apparent volume of an electrolyte divided to the molar volume of the solvent and the statistical part of its activity coefficient in concentrated solutions, as in the source mentioned there on coefficient page. Can someone access the full text of that source to extract more info?-- (talk) 14:42, 31 August 2016 (UTC)