Question

How many grams are in 8.91*10^24 atoms of Xe

Answer 1

didn't i show you this the other day? or what that someone else?
you use Avogadro's Number to figure out moles

8.91*10^24 atom Xe | 1 mol Xe
| 6.022*10^23 Divide The top by bottom which = 14.7957 mols

THEN! you have to change moles to grams by using the MM of Xe

14.7957 mol Xe | 131.29 g Xe
| 1 mol Xe Times the two top numbers which = 1942.53 or in scientific notation it would = 1.9*10^3