Question

what is the mass percent of fe in a 100 g sample of fe2o3 containing 16% pure fe2o3

Answer 1

Mass of Fe2O3= 100g

Mass of pure Fe2O3= 16% of 100g
= 16/100 × 100
= 16g
Molar mass of Fe= 56g
Molar mass of O = 16g

Molar mass of Fe2O3 = 56×2+16×3
= 160g
Ratio in which atoms of Fe and O are present in Fe2O3 = 2:3


Mass of Fe present in 160g of Fe2O3= 56×2
= 112g
Mass of Fe present in 1g of Fe2O3 = 112/160g
Mass of Fe present in 16g of Fe2O = 112/160 × 16
= 11.2g





- Abhinav Singh