Avogadro constant

From Wikipedia, the free encyclopedia
(Redirected from Avogadro's number)
Jump to: navigation, search
Value of NA[1] in various units
6.02214179(30)×1023 mol−1
2.73159757(14)×1026 lb-mol−1
1.707248479(85)×1025 oz-mol−1

The Avogadro constant (symbols: L, NA) is the number of particles (usually atoms or molecules) in one mole of a given substance.[2] Its value is equal to 6.02214129(27)×1023 mol−1.[3] The constant was named after the Italian scientist Amedeo Avogadro.

The measurement of Avogadro's constant was refined in 2011 to 6.02214078×1023 ± 0.00000018×1023.[4]

An old term closely related to the Avogadro constant is Avogadro's number. Avogadro's number is the number of atoms in 12 grams of the carbon isotope carbon-12. Avogadro's number is a dimensionless quantity and has the numerical value of the Avogadro constant given in base units.

Related pages[change | change source]

References[change | change source]

  1. Mohr, Peter J.; Taylor, Barry N.; Newell, David B. (2008). "CODATA Recommended Values of the Fundamental Physical Constants: 2006". Rev. Mod. Phys. 80: 633–730. doi:10.1103/RevModPhys.80.633. http://physics.nist.gov/cuu/Constants/codata.pdf.  Direct link to value.
  2. Johnston, Lesley (2008). Salters Advanced Chemistry: Revise Chemistry For Salters AS (Second ed.). Heinemann. p. 2. ISBN 978-0-435-63154-3. 
  3. "Avogadro constant". National Institute of Standards and Technology. Retrieved 2013-11-07. 
  4. Andreas, Birk (2011). "Determination of the Avogadro Constant by counting the atoms in a 28Si Crystal". Physical Review Letters 106 (3). doi:10.1103/PhysRevLett.106.030801.