Question

Calculate the percentage composition of iron in a ferric oxide ($F{e}_2{O}_3$).

(Atomic mass of $Fe=56$)

• A. 70% $Fe$
• B. 30% $Fe$
• C. 40% $Fe$
• D. 56.5% $Fe$

Answer 1

The correct option is A 70% $Fe$

Molecular weight of ${Fe}_2{O}_3=56\times 2+16\times 3=112+48=160g$

$160g$ of ${Fe}_2{O}_3$ contains $112g$ of $Fe$

$\therefore$ % of $Fe$ $=\frac{112}{160}\times 100=70$%