What mass of iron is present in a 100*g mass of "ferric oxide"?

Sep 26, 2016

Approx. $70 \cdot g$.

Explanation:

The molecular mass of $\text{ferric oxide, } F {e}_{2} {O}_{3}$ is $159.69 \cdot g \cdot m o {l}^{-} 1$.

$\text{Moles of ferric oxide}$ $=$ $\text{Mass"/"Molar mass}$ $=$ $\frac{100 \cdot g}{159.69 \cdot g \cdot m o {l}^{-} 1}$ $=$ $0.626 \cdot m o l$

And thus in a $100 \cdot g$ sample there are $2 \times 0.626 \cdot m o l \times 55.85 \cdot g \cdot m o {l}^{-} 1$ of iron metal.

And thus iron content $=$ $0.626 \cdot m o l \times 2 \times 55.85 \cdot g \cdot m o {l}^{-} 1$

$=$ ??g.