Question

balance the following reaction:
fe + o₂ → fe₂o₃

Explanation:

Step1: Balance oxygen atoms

$$O_2 ightarrow Fe_2O_3$$

The least - common multiple of 2 (from $O_2$) and 3 (from $Fe_2O_3$) is 6. So we put a 3 in front of $O_2$ and a 2 in front of $Fe_2O_3$: $3O_2
ightarrow 2Fe_2O_3$

Step2: Balance iron atoms

Now, looking at the iron atoms. In $2Fe_2O_3$, there are 4 iron atoms. So we put a 4 in front of Fe: $4Fe + 3O_2
ightarrow 2Fe_2O_3$

Answer:

$4Fe + 3O_2
ightarrow 2Fe_2O_3$