Question

The mass of a single gold atom is 3.27×10-22 grams. How many gold atoms would there be in 70.6 milligrams of gold?

Answer 1

[Total mass of gold atoms] = [Mass of one gold atom] x [number of gold atoms]

divide both sides by mass of one atom:

[Total mass of gold atoms] / [Mass of one gold atom] = [number of gold atoms]

(0.130 grams) / (3.27E-22 grams/atom) = 3.975535168E20 or 397 quintillion gold atoms.