Mole Day - National Chemistry Week

Mole Day is Oct 23.  More specifically, Mole Minute is 6:02AM on Oct 23!

It was named Mole Day because when it the date/time is written out ( 6:02 10/23 ) it symbolizes Avogadro's number 6.02 x 1023 ! Mole Day has it's own organization which features an amusing "Pledge of Allegiance!" 

National Chemistry WeekThe week that includes Oct 23 is generally declared to be National Chemistry Week and is celebrated by the American Chemical Society. In 2009 it is the week of October Oct.18-24, and the theme is "“Chemistry - It's Elemental".

NIST provides a definition of the mole as well as the presently accepted value for Avogadro's number.  This is called into question by a recent study ( Ref 1 ) done in Germany.  X-ray diffraction was used to calculate the exact separation between silicon atoms in a 1 kilogram, 10 cm diameter billet of pure silicon. If the separation is accurately and precisely known, Avogadro's number can be calculated from the known mass and dimensions of the billet. Although the relative precision of the measurement is good (3.4x10-7), it differs from the accepted value by nearly three times that amount! If the precision can be improved, and the accuracy question answered, this measurement could lead to an absolute definition of the kilogram.

To Electrochemistry and Beyond! To Electrochemistry and Beyond!

Becker, P.  et al. Determination of the Avogadro Constant via the Silicon Route. .METROLOGICA, 40 (2003), 271.  Summarized in Nature Science Update and Physics Web

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