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Realeted to mole

  1. Feb 26, 2015 #1
    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.
     
  2. jcsd
  3. Feb 26, 2015 #2

    DrDu

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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.
     
  4. Feb 26, 2015 #3
    But why
    1 mole ⇒6.022*1023 atoms is their any derivation for it.
     
  5. Feb 26, 2015 #4

    DrDu

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    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 ammount might contain.
     
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