If I measure 12 grams of carbon 12 I have 1 mole of carbon 12. How do I measure it in a weightless state. I can't count molecules to 6.02 x 10^23 and then say I have 1 mole and therefore 12 grams of carbon 12...
Of course you can't count a Mol of atoms. You put a mass of
n Mols of a substance on a scale and measure the effect of the gravitational acceleration on it as the mass impinges on the scale apparatus and determine its weight. You're not really measuring its mass with the scale. Rather, you're extrapolating the mass using an equation specific to the gravitational field (Earth). You know the weight (W) and the force (g) so all you need do is rearrange the equation and isolate mass: m = W/g (m = F/a).
Take the same mass to the Moon and it will weigh only 1/6th but the mass will be the same. Why? The gravitational acceleration is only 1/6th with reference to Earth but
n Mols is
n Mols is
n Mols: 6.02 * 10^23
n atoms (discounting radionuclide decay).
What's actually going on with mass versus weight is that in common use we tend to use the wrong term. It's not a problem because we understand what we mean when talking informally. But in a physics or chem lab the terms are not interchangeable and using them loosely introduces unintentional vagueness and errors. Mass is a scalar and rest mass is a constant in the Newtonian weak field, low velocity limits. Weight is the "F" in F = ma. Mass is included as part of the
definition of weight. If mass is one part of a two part definition of weight then mass, obviously, cannot be weight.
Eistein's problem understanding much of physics is his misapprehension that standing on the surface of the Earth you are not subject to a constant gravitational acceleration. You are. I've told him on more than one occassion that he fails to fully analyze his physics problems, specifically the forces involved and conservation laws. The same is true with this one. I'll ask you: You're receiving a constant gravitational acceleration while standing on the surface. Why don't you fall to the center of the Earth? Think about tall, marble Roman "poles" used in their buildings. The missing link's name is similar to the proper name for the "poles". Another hint: X is to one as Y is to 10^38.