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Apparently someone saw fit to undo the changes I made a few days ago to add a section to this article about other definitions of a mole (e.g., a kg-mol). He/she claimed that these changes were inappropriate as "These are not definitions of the mole." I must disagree: I have had numerous students confused by the use of kg-mol and lb-mol in textbooks, primarily because they too thought there was only one way to define a mole. Confusingly or otherwise, these definitions persist.
The term kg-mol is quite common among chemical engineers, and the lb-mol is even more common among chemical engineers from the USA. Software designed to assist in chemical plant design, such as PRO/II and ASPEN, all include these units. While these alternate definitions are rarely if ever seen outside the field of chemical engineering, their existence warrants at least being mentioned in an article dedicated to the definition of a mole.
Examples:
M. S. Peters, K. Timmerhaus, and R. E. West, Plant Design and Economics for Chemical Engineers, Fifth Edition. McGraw Hill (2002-2003). [Uses kg-mol, written as such.]
J. M. Douglas, Conceptual Design of Chemical Processes. Boston: McGraw Hill (1988). [Uses lb-mol, written as mol, throughout.]
Kaiserkarl13 (talk) 21:46, 20 January 2009 (UTC)
The pound-mole (also written without the hyphen) is a separate unit, although the link currently redirects here. The "kilogram-mole" is just an obsolescent name for the kilomole. Both of them are units of measurement of amount of substance that can be found in some US texts, but neither of them is the same unit as the mole. The confusion only arises if you pretend that they are. Physchim62 (talk) 22:12, 20 January 2009 (UTC)
The fact that pound-moles and kilogram-moles are separate units but are still called moles was my point! The fact that kilomoles and kilogram-moles are the same is a result of the fact that kilo(grams) and (kilograms) are the same, but the kg-mol is in no way an obsolete unit---it just happens to have the same meaning as a kmol and takes more characters to type. The purpose of the added text is to point out that there is more than one definition of a mole---with the standard SI unit of a mole being defined in terms of the gram. There's nothing pretend about it, though---the units kg-mol and lb-mol still occur, and they are no less valid as definitions of a mole. They just aren't the ones associated with the SI definition of "the mole." Kaiserkarl13 (talk) 23:00, 20 January 2009 (UTC)
You'd never say that pounds are another way of defining grams, so why do you say that the pound-mole is another way of defining the mole? It's another way of defining a unit of amount of substance, yes, but there is no law that says that all units of amount of substance have to be called "moles": in fact, there is a good pedagogical case for pointing out the exact opposite! Physchim62 (talk) 23:14, 20 January 2009 (UTC)
I'm not contending that the specific unit referred to as the mole (i.e., the SI unit defined as the number of entities in 12 g of 12-C) is the same unit as a kilogram-mole---obviously it isn't. The point of contention is that other units of amount of substance are invariably also called moles (with some modifier), perhaps merely due to lack of creativity. An excellent example is the unfortunate use of pounds in the English Imperial System to refer to both units of force and mass (these are, of course, different but related units). I think this point of contention could be settled by adding a section titled something like, "Units related to the mole" in which other units of amount of substance are defined. This would have the advantage of clarifying that "the mole" (unit) and "a mole" (generic term for amount of substance, usually but not always referring to the SI unit) can be different things. This would also solve the problem of pound-mole and kilogram-mole currently redirecting to Mole_(unit), which doesn't mention either of these other units. I may write these articles at a later date when I have the time. Kaiserkarl13 (talk) 21:35, 21 January 2009 (UTC)
Possibly this should be "Other units called mole" or something on those lines? That would make it clear that the lb-mole and kg-mole (both of which redirect here) are not actually the mole but rather something else with a confusingly similar name… I think I'll go add that. —Preceding unsigned comment added by Sabik (talk • contribs) 16:15, 27 January 2009 (UTC)
I have re-written the section, trying to be brief and non-contentious, while giving a source and giving the style of an encylopedia. I hope this helps. Chemical Engineer (talk) 17:52, 5 February 2009 (UTC)
把关于这个单位的讨论也贴上来，他们自己对这个单位似乎也很混乱！ |
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