Tracy P. Hamilton
Posts: 1239
Joined: May 2006
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| Quote (REC @ Mar. 06 2012,19:47) | | Quote (Occam's Aftershave @ Mar. 06 2012,19:23) | | Quote (khan @ Mar. 06 2012,19:14) | | Quote (Occam's Aftershave @ Mar. 06 2012,19:45) | | Quote (Joe G @ Mar. 06 2012,17:51) | | Yes, I know- what I didn't know is if you were using some sort of shorthand for "molecule" |
Jeezus tittyfuckin' christ.... :D :D :D |
Shit, I recall most of this stuff from 10th grade (1965 for those keeping track). |
Same here but in the late 70's, although I learned Avogadro's number as 6.023x10e23, not 6.022
Did the measurement get more precise? |
Determination of the Avogadro Constant by Counting the Atoms in a 28Si Crystal
published 18 January 2011
The Avogadro constant links the atomic and the macroscopic properties of matter. Since the molar Planck constant is well known via the measurement of the Rydberg constant, it is also closely related to the Planck constant. In addition, its accurate determination is of paramount importance for a definition of the kilogram in terms of a fundamental constant. We describe a new approach for its determination by counting the atoms in 1 kg single-crystal spheres, which are highly enriched with the 28Si isotope. It enabled isotope dilution mass spectroscopy to determine the molar mass of the silicon crystal with unprecedented accuracy. The value obtained, Na=6.02214078(18)×10^-23 mol-1, is the most accurate input datum for a new definition of the kilogram.
http://link.aps.org/doi.........030801 |
In case it is not clear, the kg standard will be based on an exact number for Avogadro's constant within 3 years.
Just like an inch is defined as EXACTLY 2.54 cm now.
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"Following what I just wrote about fitness, you’re taking refuge in what we see in the world." PaV
"The simple equation F = MA leads to the concept of four-dimensional space." GilDodgen
"We have no brain, I don't, for thinking." Robert Byers
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