Talk:Molar volume

molecular volume??
Is the symbol 'M' also used for a 1 molar solution? Both halophile and extremophile use this convention (unwikified), and IIRC, it is what I was taught in my high school chemistry. CS Miller 15:59, May 19, 2004 (UTC)
 * Thinking about it, I think 1M is a mole per litre.

The molar volume is the volume occupied by 1 mole of a gas. Conditions must be specified.

From IUPAC: standard conditions for gases Temperature, 273.15 K (°C) and pressure of $$10^5$$ pascals. IUPAC recommends that the former use of the pressure of 1 atm as standard pressure (equivalent to 101'325 Pa) should be discontinued.

normal The term ‘normal’ in e.g. ‘normal boiling temperature’ means the value at a pressure of 101'325 Pa. --Yvanduvent 01:01, 4 October 2005 (UTC)

Some minor but important changes
Molar volumes are used in many physical sciences other than chemistry and are also widely used by chemical engineers and other engineers. I realize full well that the cognoscenti of the chemistry field (i.e., those very knowledgeable of chemistry) are aware of the fact that term "mole" or "mol" refers to a gram mole. But engineers and others quite often use "kilogram mole" and "kgmol". Thus, it behooves us to be sure that we clearly differentiate between a gram mole and a kilogram mole. Therefore, I changed all of the usage of "mole" and "mol" in this article to "gram mole" and "gmol" respectively.

I also changed the usage of K to °K wherever Kelvin temperatures were used. The statement "It can be computed as the substance's atomic or molecular weight, divided by its density" was not correct. For a gas, only the molecular weight can be used. Therefore, I also changed that statement. mbeychok 05:56, 4 February 2006 (UTC)


 * I disagree with the changes of unit symbols, and have therefore changed them back. The SI units of amount of substance and temperature are mole (mol) and Kelvin (K) respectively, nothing else. To me as a chemistry student, gmol is equally confusing, as I first interpreted it as gram times mole, or gram times gram mole, if you prefer. Actually, I have after one year of chemisty studies at a European university never heard of the kilogram mole. As I changed the unit symbols to SI, I inserted a link to mole (unit), which already clarifies the difference if somebody would be confused. And what about monatomic gases? /130.243.135.145 21:35, 21 February 2006 (UTC)

Whether you find the correct units of gram mole confusing or not, the fact remains that gmol is correct and mol is ambiguous. There certainly can be no debate that kilogram mole and pound mole are acceptable units and it is therefore necessary to differentiate between the different moles.129.59.91.115

°K is absolutely a wrong unit and half to one mark will be deducted if we write this in our exam papers. We always say "x kevins" rather than "x degrees kevin".202.40.137.198 06:01, 22 March 2007 (UTC)

To give molar volume for such number of figures is senseless. If it was computed on the basis on 1 atm and 273.15 K, it can't have more than 5 figures.
 * It can have more than five significant figures, in fact, because 1 atm is exactly 101.325 kPa and 0 °C is exactly 273.15 K, both by definition. There is no experimental uncertainty in those figures, so the limitation in the number of significant figures in the calculation doesn't apply. Physchim62 (talk) 09:30, 5 October 2008 (UTC)

The Molar Volume for ideal gases is wrong
The usual way to define molar volume for ideal gas is to use the volume at 1 atm, and 0°C, so your value of 22.71 is wrong. You should rather use 101,325 Pa, and get the value of 22.41 L/mole. —Preceding unsigned comment added by Reyfari (talk • contribs) 00:56, 5 October 2008 (UTC)
 * The value given here is correct for the conditions we quote it under, ie 100 kPa: if you want a molar volume at 1 atm (101.325 kPa), simply use Boyle's law (or multiply by 100/101.325, which amounts to the same thing). Physchim62 (talk) 09:30, 5 October 2008 (UTC)

Ideal Gas Expansion
I recommend adding a basic explanation explaining why the volume of any gas, assumed to be ideal, can be found this way and how this relates to the kinetic theory of gasses. (Some reference to Avagadro's law may be helpful) Currently, the section only shows how to find the Molar Volume without any explanation of the underling principles. I think less examples and more theory is needed. If a full explanation is not appropriate perhaps some links to relevant articles could be put under the heading. I would make this expansion myself but I fear I may miss some obscure subtly in my wording and have every chemistry editor on wikipedia reprimanding me. PatxiG (talk) 03:14, 14 February 2011 (UTC)

Why is the molar gas volume constant for all ideal gases?
(for a given temperature and pressure) — Preceding unsigned comment added by 2404:E800:EA15:3A4:449D:66EE:BF7C:79E7 (talk) 23:28, 14 March 2014 (UTC)