1. Avogadro's Number

Avogadro's number tells us the number of atoms or molecules in one mole of a substance. It's approximately 6.022 x 10^23.

2. Calculation

* Divide the number of atoms by Avogadro's number:

(1.81 x 10^24 atoms S) / (6.022 x 10^23 atoms/mol) = 3.01 mol S

Answer: There are 3.01 moles of sulfur in 1.81 x 10^24 atoms of sulfur.