how many atoms are in a sample of 72.8 grams calcium ?
3 years ago Comment
first find the moles
moles of the calcium= 72.8 / 40
moles of calcium in 72.8g = 1.82mol
number of atoms= moles x Avogadro constant
atoms = 1.82 x 6.02x10+23
so the number of atoms is 1.096x10+24