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abundance, as physical quantity Mole Day, an informal holiday on October 23, was introduced among chemists of North America in honor and a reminder of the measurement unit mole for the physical quantity named amount of substance. That rather unusual academic move suggests that the introduction of the unit, as basic SI unit (like the meter and the second), carries at least some resis- tance and criticism if not controversy. The mole (abbrev. mol) is defined as an amount of substance that contains as many elementary entities (e.g. atoms, molecules, ions, electrons) as there are atoms in 12 grams of pure carbon-12 (12C). This number is called Avogadro's number and has the value 6.02214179(30)×1023. The main criticism, as I understand it, is that the mole is not a true metric (i.e. measuring) unit, rather it is a parametric unit and amount of substance is a parametric base quantity. The minimum to be done, some critics say, is to define the number of constituents in the mole to be equal to exactly 6.02214×1023 . While I don’t have any nightmares about unit called mole, I oppose the name of its physical quantity. Although the definition of mole involves the substance, isotope 12C, it is simply a number, the number of constituents in a given volume or physical system or whatever. You don’t see any particular substance behind the number, you just try to find out ‘how many’. The unit mole might not be practical to express the number of pigs or oranges but why not the number of stars in a galaxy clusters? The bytes of the Google servers? When SI measurement system was introduced to Croatia, the quantity measured in moles was wisely double named as koli čina tvari (the literally translation of amount of substance) and množina. Now, the best English equivalent of Croatian množina, not generally but in the context of mole, I consider to be abundance. So I’ve stated in my glossary. |
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