On Sunday 08 May 2011 23:02:16 Alan McKinnon wrote: > Apparently, though unproven, at 00:14 on Monday 09 May 2011, john did opine > > thusly: > > Great widgets. Not sure what a Molar Mass Calculator does? Perhaps > > weighs your teeth?? > : > :-) > > "Molar" as in the adjective describing "mole" as in "quantity of matter" as > in "some gigantic number of identical atoms (or maybe it's molecules)". > It's a very useful measure of "some quantity of stuff". > > IIRC the gigantic number is Avogadro's number, on the order of 10^124. So > one mole of hydrogen would be the amount of hydrogen containing that > number of hydrogen atoms (or maybe it's molecules. Whatever.)
Here's a quotation from http://en.wikipedia.org/wiki/Mole_%28unit%29: "The mole is defined as the amount of substance that contains as many elementary entities (e.g., atoms, molecules, ions, electrons) as there are atoms in 12 g of the isotope carbon-12 (12C).[1] Thus, by definition, one mole of pure 12C has a mass of exactly 12 g." (I don't know how those super- and subscript numbers will appear in e-mail.) You just knew you were setting yourself up, didn't you? :) -- Rgds Peter
