Talk:Amount of substance

message: Awagadro number is {6.022*10res power 23  — Preceding unsigned comment added by Chinmayjangid9 (talk • contribs) 13:08, 20 November 2022 (UTC)

message: Ed. May I ask your reasons for redirecting _Amount of substance_ to _Mole (unit)_ ? The former is a physical quantity; the latter is a unit for measuring the physical quantity. As such they are very different and, from the physical perspective, we need two different articles. We have this with _Length_ and _Metre_, _Mass_ and _Kilogram_, _Time_ and _Second_, _Temperature_ and _Kelvin_, etc. etc. All of these are Physical Quantities and their respective SI base units.
Thanks  Ian Cairns 21:19, 7 Jul 2004 (UTC)
replies: text: Ian, when I created the redirect every piece of information that was present in the amount of substance article was also present in the mole article, sometimes word-for-word.  As such, it seemed redundant to me and I redirected it.  If you have some additional content to add to amount of substance to make it a better standalone article, please edit over the redirect.  Even if you feel that the redirect is inappropriate and should simply be reverted to the previous page edit, go ahead.  Be bold in editing pages; that's what I was when I first created the redirect.  —Ed Cormany 00:38, 8 Jul 2004 (UTC)
replies: text:  Ed, Thanks for that. I'm happy to revert it. The physical quantity and the unit belong to different categories within the same subject area, and it helps to separate the descriptions as much as possible. Some overlap is unavoidable. However, it may well be that there is some redistribution of content possible between the articles, and I'll action this. Ian Cairns 11:14, 8 Jul 2004 (UTC)
thread_title:  Message to Ed Cormany 

message: The existence of this article is necessitated by the failure to use the term Avogadro's number as the name of the physical quantity identified by the chemical unit mole (unit), and also by the unfortunate use of the term in NIST and BIPM publications.  Using the term "amount" requires the additional explanation that it really means "quantity", and that it does not refer to mass, neither of which would have been required if the the terms "quantity of particles" or "number of particles" had been used instead.  --Blainster 17:49, 24 October 2005 (UTC)
thread_title:  Amount rather than quantity 

message: *Keep.  The keepers of our standards insist on making a distinction.  This is made clear in both BIPM's SI brochure  and in NIST's Guide for the Use of the Internaiotnal System of Units (SI).  Gene Nygaard 19:30, 24 October 2005 (UTC)
replies: text: I see that the term "amount of substance" is used in the NIST guide under 8.6.1 here but was unable to readily find it in the BIPM site.  Nevertheless, the term itself is ambiguous and thus inaccurate.  What the writers intend by using the term "amount of substance" is actually "number of particles", for which the defined quantity would be Avogadro's number.  I agree that the distinction you refer to does exist between the number or quantity of particles and the units (mole) used to measure them, and this is retained by using the term Avogadros number instead of amount of substance.  As I have noted, it would be acceptable to me to retain the article with a redirect to Avogadro's number. --Blainster 20:08, 24 October 2005 (UTC)
thread_title:  Votes for deletion 

message: Does anyone know where it comes?  —Preceding unsigned comment added by 128.214.98.177 (talk) 08:55, 9 September 2008 (UTC)
thread_title:  Symbol n? 

message: This is true. However, it might be worth letting the reader know that in the everyday work of maybe 99% of chemists and other scientists, this is irrelevant. Avogadro's constant is known to about eight significant figures, whereas typical mass measurements in the lab have no more than six. So in most cases the precision of the calculated number of entities is not limited by our knowledge of Avogadro's constant. (I say this because the section about the "Rationale for preferring amount-of-substance to absolute numbers" provides examples that talk about "chemists", and not about metrologists!) --Itub (talk) 13:22, 15 June 2009 (UTC)
replies: text: Let's not forget that the purity of most lab reagents is only three significant figures, which the BIPM puts down as the most usual limitation to the measurement of amount of substance. Physchim62 (talk) 13:32, 15 June 2009 (UTC)
thread_title:  "It is possible to measure the ratios of the numbers of entities in chemical samples more precisely than it is possible to count the absolute numbers of entities" 

message: In many wikipedia articles (Chemistry, Mole (unit), Amount of substance, Avogadro constant), there is confusion about the units of Avogadro's number N0 (should be dimensionless) and the Avogadro constant NA (dimension 1/mol). These are two different constants and should not be used as synonyms. The Avogadro constant is an official physical constant used in the SI system to convert between Amount of substance and number of entities. Because it has a unit, it is not a number. It appears in conversion of macroscopic properties (quantity per mole) to atomic properties (quantity based on a single atom or molecule). 
Avogadro's number was used widely before the unit mole for the quantity amount of substance was added to the basic SI units in the early seventies. Textbooks and teachers have not all made this transition fully, especially when it comes to problem sets and model answers. You will find many instances of the statement 1 mol = 6.022x10E23, but according to the current definitions, that statement is wrong. Saying that the name Avogadro's number was changed to the Avogadro constant is also wrong. It was a switch to different units necessitated by the new system of base units. They do have the same numeric values when using mole as the unit, but they have different dimensions, so they are different.
I'll check in a couple of days to see if anyone wishes to comment, and then revise the article accordingly if there is no objection.
Theislikerice (talk) 00:44, 18 August 2010 (UTC)
thread_title:  Avogadro's number vs. Avogadro constant 

message: It is a dimensionless quantity like the plane angle, altough it would appear dimensional. See details/explanations in mole (unit) about (pseudo)-dimensionality. Or see section above which specifies it is a ratio of number of entities.--188.26.22.131 (talk) 11:28, 24 February 2014 (UTC)
thread_title:  Dimensionless quantity 

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thread_title:  External links modified 

message: An editor has asked for a discussion to address the redirect Orders of magnitude (amount of substance). Please participate in the redirect discussion if you wish to do so.  Utopes (talk / cont) 23:39, 11 April 2020 (UTC)
thread_title:  "Orders of magnitude (amount of substance)" listed at [[Wikipedia:Redirects for discussion|Redirects for discussion]]