Avogadro's number vs. the Kofh Number

Yes, we're switching arbitrary values. Prior to 1961, physicists defined unit atomic weight as 1/16th of the mass of an oxygen-16 atom. Chemists defined it as 1/16th of the abundance-weighted average of the three oxygen isotopes present in the Earth's atmosphere. Since then it has been, by definition, 1/12 of the mass of a carbon-12 atom. (Before 1925, it was something different, but my chemistry books aren't that old.
Avagadro's number is just the number of atoms or molecules in the mass in grams of a substance that is numerically equal to the molecular weight, so it's really quite arbitrary.And by the way, Avagadro's number of avocados does, in fact, have the same mass as Earth's Moon for avocados of the unusually large mass of 122 grams each. (or 61 grams each if avocados are naturally diatomic....)

Depends on the element, and the source of the sample. The ratios of the various isotopes can vary enough for some elements to throw you off before the 4th decimal. Particularly if you're talking about Earth water vs. comet water.

It's a factual head count when you define an atomic mass unit as 1/12 of the mass of a carbon-12 atom and a gram as 1/1000 of the mass of that chunk of platinum-iridium alloy that's in Paris as the standard kilogram. If you go back to the pre-1961 definition of an amu, the number will change a little. I don't much care which it is - 15% hydrochloric acid still eats dolomite in these oil wells out here no matter what the third and fourth decimals in Avogadro's number are.

Kofh, you might want to take this up with the IUPAC, the body that decides such things. And also, you might want to cut back on whatever that is you're smoking.

Absolutely not. Like Melchior said - go find a freshman chemistry book and read about binding energy.

WTF are you babbling about now? Why don't you just decide what you really want it to be, and declare it to be so within the metes and bounds of Kofhland? I won't stand in your way.....