How many atoms does 5.06 grams of oxogen have

1.90x10²³ atoms of O

Explanation: First convert the mass of O into moles:

5.06 g O x 1 mole O / 16 g O

= 0.32 moles O

Next use Avogadro's Number to find the number of atoms of O

0.32 moles O x 6.022x10²³ atoms O / 1 mole O

= 1.90x10²³ atoms O