Question

What is the mass of 3.20x10^23 formula units of iron (III) oxide (Fe2O3)?

Answer 1

The mass of iron (III) oxide (Fe2O3) : 85.12 g

Further explanation

Given

3.20x10²³ formula units

Required

The mass

Solution

1 mole = 6.02.10²³ particles  

Can be formulated :

N = n x No

N = number of particles

n = mol

No = 6.02.10²³ = Avogadro's number

mol of Fe₂O₃ :

$\tt n=\dfrac{3.2.10^{23}}{6.02.10^{23}}=0.532$

mass of Fe₂O₃ (MW=160 g/mol)

$\tt mass=mol\times MW=0.532\times 160=85.12~g$