Question

What is the weight of 6.3 × 10
21
atoms of
phosphorus?
Answer in units of g

Answer 1

1mol of any substance = 6.022 * 10^23 elementary entities of that substance (be it atoms, molecules or whatever. Think of it as the chemist's "dozen" only it's 6.022 * 10^23 rather than 12.)

For finding the amount of grams in 1 mol of an element, find the element's atmoic mass and that number is the amount of grams.

6.3 * 10^21 P atoms * 1mol of P/6.022 * 10^23 P atoms * 30.97g of P/mol = 0.324g of Phosphorus.

Answer 2

Erm, *atomic mass, sorry.