Question

Calculate mass % of different elements present
in Fe2o3.​

Answer 1

Explanation:

i) Molecular weight of Fe

2

O

3

=(56×2)+(16×3)=160g

Molar mass of Fe in 1 mole of Fe

2

O

3

=56×2=112g

Therefore %age composition of Fe in Fe

2

O

3

=

MolecularweightofFe

2

O

3

molarmassofFe

×100=

160

112

×100=70%

ii) Molecular weight of Urea( H

2

NCONH

2

) =2+14+12+16+2+14=60g

Molar mass of N in 1 mole of Urea =2×14=28g

Therefore %age composition of N in Urea =

Molecular weight ofH

2

NCONH

2

molarmassofN

×100=

60

28

×100=46.6%