Answer:
1.51×10²³
Explanation:
Convert to moles first
moles=mass/molar mass
moles=8.00/32 (molar mass of oxygen is multiplied by 2 since it is diatomic)
moles=1/4
multiply moles with Avogadro's constant
1/4*6.02×10²³
1.505×10²³
1.51×10²³ molecules of O₂ are in 8.00 grams of Oxygen.