4 Fe (s) + 3 O₂ (g) → 2 Fe₂O₃ (s)
Explanation:
* Fe (s) represents iron metal in its solid state.
* O₂ (g) represents oxygen gas.
* Fe₂O₃ (s) represents iron(III) oxide, also known as rust, in its solid state.
What happens in the reaction:
1. Iron atoms on the surface of the metal react with oxygen molecules in the air.
2. This reaction requires activation energy, which can be provided by heat or a spark.
3. The iron atoms lose electrons, forming iron(III) ions (Fe³⁺).
4. The oxygen molecules gain electrons, forming oxide ions (O²⁻).
5. These ions combine to form iron(III) oxide (Fe₂O₃), a solid compound that forms the reddish-brown layer of rust.
Note:
* This reaction is exothermic, meaning it releases heat.
* The rust formation process is relatively slow at room temperature but accelerates in the presence of moisture and certain salts.
