Question

Aluminum metal and manganese (IV) oxide react to produce aluminum oxide and manganese metal. What mass of manganese (IV) oxide reacts to produce 1.12kg of manganese metal?

Answer 1

Answer: 1.77 kg of manganese (IV) oxide reacts to produce 1.12kg of manganese metal.

Explanation:

The balanced chemical equation is:

$4Al+3MnO_2\rightarrow 2Al_2O_3+3Mn$

To calculate the moles, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text {Molar mass}}$

moles of manganese = $\frac{1.12\times 1000g}{55g/mol}=20.4mol$

According to stoichiometry :

3 moles of $Mn$ is produced by = 3 moles of $MnO_2$

Thus 20.4 moles of $Mn$ is produced by =$\frac{3}{3}\times 20.4=20.4moles$  of $MnO_2$

Mass of $MnO_2=moles\times {\text {Molar mass}}=20.4moles\times 86.9g/mol=1773g=1.773kg$    (1kg=1000g)

Thus 1.77 kg of manganese (IV) oxide reacts to produce 1.12kg of manganese metal.