Avogadro's constant: Difference between revisions

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The [[SI]] definition of '''Avogadro's constant''' (designated  ''N''<sub>A</sub>) is: the number of entities (such as atoms, ions,  or molecules) per [[mole (unit)|mole]]. (This definition requires a definition of mole that does not rely on ''N''<sub>A</sub>, but one that is in terms of <sup>12</sup>C atoms). The constant ''N''<sub>A</sub> has dimension mol<sup>&minus;1</sup>.  
The [[SI]] definition of '''Avogadro's constant''' (designated  ''N''<sub>A</sub>) is: the number of entities (such as atoms, ions,  or molecules) per [[mole (unit)|mole]]. (This definition requires a definition of mole that does not rely on ''N''<sub>A</sub>, but one that is in terms of <sup>12</sup>C atoms). The constant ''N''<sub>A</sub> has dimension mol<sup>&minus;1</sup>.  
The numeric value of Avogadro's constant is ''N''<sub>A</sub> = 6.022&thinsp;141&thinsp;79   x 10<sup>23</sup> mol<sup>&minus;1</sup>.  
The numeric value of Avogadro's constant is ''N''<sub>A</sub> = 6.022&thinsp;140&thinsp;76   x 10<sup>23</sup> mol<sup>&minus;1</sup>.  


Because the mole and  Avogadro's number are defined in terms of the atomic mass constant (one twelfth of the mass of a <sup>12</sup>C atom), Avogadro's ''constant'' and ''number'' have by definition the same numerical value. In practice the two terms are used interchangeably.
Reference:
 
https://www.nist.gov/si-redefinition/meet-constants

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See for more details Avogadro's number.

The SI definition of Avogadro's constant (designated NA) is: the number of entities (such as atoms, ions, or molecules) per mole. (This definition requires a definition of mole that does not rely on NA, but one that is in terms of 12C atoms). The constant NA has dimension mol−1. The numeric value of Avogadro's constant is NA = 6.022 140 76 x 1023 mol−1.

Reference:

https://www.nist.gov/si-redefinition/meet-constants