The chemical equation provided shows iron rusting to form iron oxide. Use the drop-down menu to choose the coefficients that will balance the chemical equation.

Question

(
)Fe + (
)O2 → (
)Fe2O3

Answer 1

To balance the chemical equation for the rusting of iron which forms iron(III) oxide (Fe₂O₃), you will need to find the correct coefficients.

The unbalanced equation is:

$\text{Fe}+{\text{O}}_2\to {\text{Fe}}_2{\text{O}}_3$

To balance it:

• There are 2 iron (Fe) atoms in iron(III) oxide (Fe₂O₃), so you need 2 Fe on the left:

  $2\text{Fe}+{\text{O}}_2\to {\text{Fe}}_2{\text{O}}_3$

• In Fe₂O₃, there are 3 oxygen (O) atoms. Since O₂ is diatomic (contains 2 O atoms), you will need 1.5 O₂ to get 3 O atoms. However, to avoid using a fractional coefficient, we can multiply the entire equation by 2:

This gives:

$4\text{Fe}+3{\text{O}}_2\to 2{\text{Fe}}_2{\text{O}}_3$

So the balanced coefficients are:

4 for Fe, 3 for O₂, and 2 for Fe₂O₃.

Therefore, the balanced equation is:

$\mathbf{4}\text{Fe}+\mathbf{3}{\text{O}}_2\to \mathbf{2}{\text{Fe}}_2{\text{O}}_3$