Mole: Avogadro's Number & Its Discovery

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Discussion Overview

The discussion centers around the concept of a mole and Avogadro's number, specifically questioning why one mole is defined as 6.022 x 1023 atoms and the historical context of its determination. Participants explore the definitions, derivations, and empirical nature of this constant.

Discussion Character

  • Exploratory, Technical explanation, Conceptual clarification, Debate/contested

Main Points Raised

  • One participant questions why 1 mole is defined as 6.022 x 1023 atoms and seeks a derivation for this number.
  • Another participant asserts that Avogadro did not determine this number, noting that it was first approximated by Loschmidt in 1865 and that the mole was originally defined based on the number of atoms in 1g of hydrogen gas.
  • A different viewpoint emphasizes that the definition of the gram is arbitrary and that the number of atoms in one mole is empirical, referencing the historical context of the gram's definition related to water.

Areas of Agreement / Disagreement

Participants express differing views on the historical attribution of Avogadro's number and the nature of its definition. There is no consensus on the derivation of the number or its empirical basis.

Contextual Notes

Participants note the limitations of historical definitions and the lack of instruments at the time of Avogadro, which may affect the understanding of how the number was determined.

akashpandey
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Why there is
1mole⇒6.022*1023 atom.
Why there is not another number.
How avogrado find that number exactely correct at that time where there was no instuments.
 
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Avogadro did not find that number, it was only named after him. It's approximate value was first determined by Loschmidt in 1865:
http://books.google.de/books?id=ppEAAAAAYAAJ&pg=PA395#v=onepage&q&f=false
One mole was first defined as the number of atoms in 1g of hydrogen gas. As 1g is a fundamental unit in the cgs system, which is until today the preferred unit system in theoretical physics, this setting seems quite reasonable.
 
But why
1 mole ⇒6.022*1023 atoms is their any derivation for it.
 
It is the definition of the gram which is arbitrary and the number of atoms in one mole is purely empirical. The original definition of the gram was the mass of 1 cubic centimetre of water. At that time (end of the 18th century), one had no idea about the number of molecules that this amount might contain.
 

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