Accreditation and Quality Assurance

, Volume 19, Issue 3, pp 213–220 | Cite as

The mole is an Avogadro number of entities, the macroscopic unit for chemical amount

Discussion Forum

Abstract

Just as the gram is an Avogadro number of daltons, g = (g/Da) Da, the current definition of the mole can be interpreted as an Avogadro number of entities, as it is often thought of by chemists—and it should be explicitly redefined this way. By introducing a hitherto missing atomic-scale unit for the amount of any substance, the entity (symbol ent), analogous to the dalton for mass, we can then define the mole as: mol = (g/Da) ent—i.e., an Avogadro number of entities. It is argued that the name for the base quantity should be “chemical amount,” by analogy with “electric current.” Recent proposals and counterproposals for redefining the mole (and renaming “amount of substance”) are critically discussed in light of the above intuitively obvious definition.

Keywords

Redefinition of mole Avogadro number Avogadro constant Entity New SI Chemical amount Amount of substance Number of entities 

References

  1. 1.
    De Bièvre P (2013) Second opportunity for chemists to re-think the mole. Accred Qual Assur 18:537–540CrossRefGoogle Scholar
  2. 2.
  3. 3.
    Leonard BP (2010) Comments on recent proposals for redefining the mole and kilogram. Metrologia 47:L5–L8CrossRefGoogle Scholar
  4. 4.
    Leonard BP (2012) Why the dalton should be redefined exactly in terms of the kilogram. Metrologia 49:487–491CrossRefGoogle Scholar
  5. 5.
    Leonard BP (2007) The atomic-scale unit, entity: key to a direct and easily understood definition of the SI base unit for amount of substance. Metrologia 44:402–406CrossRefGoogle Scholar
  6. 6.
    Leonard BP (2011) Alternative interpretations of the mole and the ideal gas equation. Accred Qual Assur 16:577–581CrossRefGoogle Scholar
  7. 7.
    Curti C (2001) Several meanings of Avogadro number and their utilization in stoichiometry. http://www.chmsoft.com/avogadro/index.html
  8. 8.
    Morikawa T, Newbold BT (2004) ‘Amount of substance’ and a single elementary entity. Chemistry (Bulg J Chem Educ) 13:431–435Google Scholar
  9. 9.
    Nelson PG (2011) What is the mole? Found Chem 5:3–11Google Scholar
  10. 10.
    Mills IM, Mohr PJ, Quinn TJ, Taylor BN, Williams ER (2005) Redefinition of the kilogram: a decision whose time has come. Metrologia 42:71–80CrossRefGoogle Scholar
  11. 11.
  12. 12.
    Brownstein KR (1997) Angles—let’s treat them squarely. Am J Phys 65(7):605–614CrossRefGoogle Scholar
  13. 13.
    Mills IM, Mohr PJ, Quinn TJ, Taylor BN, Williams ER (2006) Redefinition of the kilogram, ampere, kelvin and mole: a proposed approach to implementing CIPM recommendation 1 (CI–2005). Metrologia 43:227–246CrossRefGoogle Scholar
  14. 14.
    Milton MJT, Mills IM (2009) Amount of substance and the mole. Chimia 63:613–615CrossRefGoogle Scholar
  15. 15.
    Johansson I (2011) The mole is not an ordinary measurement unit. Accred Qual Assur 16:467–470CrossRefGoogle Scholar
  16. 16.
    Milton MJT (2013) The mole, amount of substance and primary methods. Metrologia 50:158–163CrossRefGoogle Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 2014

Authors and Affiliations

  1. 1.The University of AkronAkronUSA

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