Arun
Last Activity: 6 Years ago
1 amu = 1.66 x 10-24 grams
126 amu = 126 x 1.66 x 10-24
= 209.16 x 10-24 grams
1 mole HNO3 = 63.01 g
Hence 209.16 x 10-24 grams = 3.32 x 10-24 moles
1 mole = 6.023 x 1023 molecules
hence 3.32 x 10-24 moles = 19.99 x 10-23 molecules
1 molecule of HNO3 contains 5 atoms.
Hence, 19.99 x 10-23 molecules = 99.96 x 10-23 atoms
Therefore, 126 amu of HNO3 contains 99.96 x 10-23 atoms.