3 ms·
Definition of mole changes too. One mole contains exactly 6.022 140 76×10²³ elementary entities (as opposed to the number of atoms in 12 grams of ¹²C). Effecti
by lelf 7y ago
Definition of mole changes too.
One mole contains exactly 6.022 140 76×10²³ elementary entities (as opposed to the number of atoms in 12 grams of ¹²C). Effective 20 May 2019.
- Izkata 7y agoEh? Straight 6.022*10^23 is what I learned in highschool chemistry in 2003..
- kfichter 7y agoIt's being slightly tweaked: https://chemistry.stackexchange.com/questions/91692/avogadros-number-6-023-x-1023-or-6-022-x-1023 https://chemistry.stackexchange.com/questions/91692/avogadro...
- hexane360 7y agoThe difference is more epistemological than practical. Before, 6.022x10^23 was the measured value of the conversion factor between a gram (exactly 1/100 of the Prototype Kilogram) and a dalton (exactly 1/12 the mass of a carbon-12 atom). After the redefinition, a dalton is defined as being 1/6.022x10^23th of a gram, and measured to be approximately equal to 1/12 the mass of a carbon-12 atom. In essence, the dependency chain was reversed, so now it all flows from the kilogram outwards.
- gubbrora 7y agoThe real wtf is that we had a unitless unit, ie a number whose value changes over time with some reference object.