Question

When iron (Fe, gram atomic mass=56 g) is exposed to the atmospheric oxygen, it results in the formation of rust (${\text{Fe}}_2{\text{O}}_3$, gram molecular mass=160 g). If 1120 g of ${\text{Fe}}_2{\text{O}}_3$ is formed, how many moles of ${\text{Fe}}_2{\text{O}}_3$ is formed?

Answer 1

<!--td {border: 1px solid #ccc;}br {mso-data-placement:same-cell;}--> Given mass of ${\text{Fe}}_2{\text{O}}_3$ = 1120 $\text{g}$
Gram molecular mass of ${\text{Fe}}_2{\text{O}}_3$ = 160 $\text{g}$

Number of moles = $\frac{\text{Given mass}}{\text{Gram molecular mass}}$
$\therefore$ Number of moles of ${\text{Fe}}_2{\text{O}}_3$ = $\frac{1120}{\text{160}}$ = $\text{7}\text{mol}$