Question

equation for when iron metal is strongly heated in air

Answer 1

Iron (III) + oxygen = Iron (III) Oxide 

Fe(+3) + O2 -> Fe2O3 


Balanced Version: 
4 Fe + 3 O2 -> 2Fe2O3 

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Answer 2

Answer:

When iron metal is ‘strongly heated’ in air, iron oxide is formed.  

Explanation:

When iron metal is ‘strongly heated’ in air, iron oxide is formed. This happens since, iron, which is mainly in ferric (Fe(III)) state combined with the Oxygen in the air when heated in the air. The Iron (III) oxide is thus formed $\left(\mathrm{Fe}_{2} \mathrm{O}_{3}\right)$.  

The equation or reaction is as follows:

Iron (III) + Oxygen = Iron (III) Oxide  

$\mathrm{Fe}^{(+3)}+\mathrm{O}^{(-2)} \rightarrow \mathrm{Fe}_{2} \mathrm{O}_{3}$

On Balancing the above equation, we get:

$4 \mathrm{Fe}+3 \mathrm{O}_{2} \rightarrow 2 \mathrm{Fe}_{2} \mathrm{O}_{3}$