Question

Given the following equation: 4 Fe + 3022 Fe2O3 What mass of iron is needed

Answer 1

Answer : The mass of iron needed is 29.5 grams.

Explanation : Given,

Mass of $O_2$ = 12 g

Molar mass of $O_2$ = 32 g/mol

First we have to calculate the moles of $O_2$.

$\text{Moles of }O_2=\frac{\text{Given mass }O_2}{\text{Molar mass }O_2}$

$\text{Moles of }O_2=\frac{12g}{32g/mol}=0.375mol$

Now we have to calculate the moles of $Fe$

The balanced chemical equation is:

$4Fe+3O_2\rightarrow 2Fe_2O_3$

From the reaction, we conclude that

As, 3 moles of $O_2$ react with 4 moles of $Fe$

So, 0.375 mole of $O_2$ react with $\frac{4}{3}\times 0.375=0.5$ mole of $Fe$

Now we have to calculate the mass of $Fe$

$\text{ Mass of }Fe=\text{ Moles of }Fe\times \text{ Molar mass of }Fe$

Molar mass of $Fe$ = 59 g/mole

$\text{ Mass of }Fe=(0.5moles)\times (59g/mole)=29.5g$

Therefore, the mass of iron needed is 29.5 grams.