Answer
$$4 \space Fe(s) + 3 \space O_2(g) \longrightarrow 2 \space Fe_2O_3(s) $$
Work Step by Step
1. Identify the chemical compounds:
Solid iron: $Fe(s)$
Gaseous oxygen: $O_2(g)$
Solid iron(III) oxide: $Fe_2O_3(s)$
2. Write the unbalanced reaction.
$$Fe(s) + O_2(g) \longrightarrow Fe_2O_3(s) $$
- Balance the number of iron atoms:
$$2 \space Fe(s) + O_2(g) \longrightarrow Fe_2O_3(s) $$
- Balance the number of oxygen atoms:
$$2 \space Fe(s) + \frac 32 \space O_2(g) \longrightarrow Fe_2O_3(s) $$
- Multiply all coefficients by 2:
$$4 \space Fe(s) + 3 \space O_2(g) \longrightarrow 2 \space Fe_2O_3(s) $$
