What is the Avogadro constant?
The Avogadro constant is N_A = 6.02214076e23 /mol, exact by SI definition (zero uncertainty). It is the number of entities in one mole.
Open the interactive PhysRef tool →Key facts
| Value | 6.02214076e23 mol^-1 |
|---|---|
| Symbol | N_A |
| Exactness | Exact by SI definition (uncertainty 0) |
| Meaning | Entities per mole |
| Source | CODATA 2018 |
Frequently asked questions
What is Avogadro's number?
N_A = 6.02214076e23 per mole, the fixed number of atoms or molecules in one mole since the 2019 SI redefinition.
Is Avogadro's number exact?
Yes. Since 2019 it is an exact defining constant of the SI with zero uncertainty.
What is a mole?
A mole is exactly 6.02214076e23 elementary entities, such as atoms, molecules, or ions.
Related pages
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