How do I find the number of atoms using a chemical formula? ex: 4 HNO3

you should

MOL × NA(Avogadro Constant)

Mol = 4

HNO3 = 5 Atome ( 1H + 1N + 3O)

NA = 6.02 × 10* ( * = 23)

2.408 x 10^24

GREETINGS!

One mole of a substance is equal to 6.02 × 10²³ units of that substance. The number 6.022 × 10²³ is known as Avogadro's number.

so if one mole of molecule is equal to that number so,

                              for 4 moles of = 4 x ()

so answer is,

                      2.408 x 10^24

HOPE IT HELPS YOU.