Question

how many moles of Fe2O3 are there in 320kg of iron 3 oxide ( 1kg =1000g)

Answer 1

Fe2O3 : 2×56 + 3×16
= 160g = 1 mole.
1kg = 1000g
320kg = 320000g

(by using unitary method)

Moles. Molecular weight
1. 160
X. 320000

X = 2000moles.


Hope it helps................

Answer 2

molecular weight of Fe2O3 = 2× atomic wt of Fe +3× atomic wt of O
= 2× 56 + 3× 16 = 112 + 48 = 160 g/mol

now,
mole = given wt/molecular wt
=320× 10³/160
=2× 10³ moles
= 2000 moles