The number of moles of ozone atoms in 3.2 g of ozone is …

Given:
m (O3) = 3.2 g

To find:
n (O in O3) -?

Solution:
1) Using the periodic system of D.I.Mendeleev, calculate the molar mass of ozone:
M (O3) = Mr (O3) = Ar (O) * N (O) = 16 * 3 = 48 g / mol;
2) Calculate the amount of ozone substance:
n (O3) = m (O3) / M (O3) = 3.2 / 48 = 0.07 mol;
3) Calculate the amount of oxygen in ozone:
n (O in O3) = n (O3) * N (O) = 0.07 * 3 = 0.21 mol.

Answer: The amount of substance O in O3 is 0.21 mol