Calculate the mass, in grams, of Avogadro's number of calcium atoms.

Required data to solve this problem:

This is a unit analysis problem wherein we are given Avogadro's number and we're trying to output a mass in grams.  Molar mass can be used as a conversion factor, since molar mass is in units of grams per mole.  Since we know that Avogadro's number is equal to one mole, we can set up a unit analysis to go from Avogadro's number to grams, with moles as the middleman, so to speak.

The moles cancel and the answer is Avogadro's number divided by 40.078.

1.503x10²² grams

gravity causes stares to cluster i think so

the old alchemists made significant contributions to science even though there starting premises were off a bit. their conclusions after failure would steer them into better directions for investigation. science is no more than close observation and the initial mistakes result in rethinking and retrying experiments.