Some Basic Concepts of Chemistry Part 2

Molar mass of C7H5N3O6
=12×7+5+14×3+16×6
=227‌gm
Given mass of C7H5N3O6=681‌gm
∴ Moles of C7H5N3O6=‌

681

227

=3
In one molecule of C7H5N3O6,3N atoms present.
∴ In 1 mole C7H5N3O6,3 moles of N atoms presents.
∴ In 3 moles of C7H5N3O6,3×3=9 moles of N atoms presents.
We know, 1 mole of N atoms =6.02×1023N atoms.
∴9 moles of N atoms =9×6.02×1023=54.18×1023=5418×1021