Here's how to calculate the number of moles of phosphorus (P) in the given sample:

1. Avogadro's Number:

* Avogadro's number tells us that there are 6.022 x 10^23 atoms in one mole of any element.

2. Calculation:

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

(3.78 x 10^24 atoms) / (6.022 x 10^23 atoms/mol) = 6.28 moles of P

Therefore, there are approximately 6.28 moles of phosphorus (P) in the sample.