Question

How many atoms are in 15.0 moles of C2H6O

Answer 1

Answer: $813.1\times 10^{23}$ atoms.

Explanation:

According to avogadro's law, 1 mole of every substance weighs equal to the molecular mass and contains avogadro's number $6.023\times 10^{23}$ of particles.

1 molecule of $C_2H_6O$ contains = 9 atoms

1 mole of $C_2H_6O$ contains = $9 \times 6.023\times 10^{23}=54.21\times 10^{23}$ atoms

Thus 15 moles $C_2H_6O$ contains =$\frac{54.21\times 10^{23}}{1}\times 15=813.1\times 10^{23}$ atoms.

Thus the answer is $813.1\times 10^{23}$ atoms.

Answer 2

1 mole = 6.22 x 10^23 molecules (Avogadro's number)
15 moles x (6.22 x 10^23) = 9.33 x 10^24 atoms