Question

After cooking the hot dogs, your friend's mom reminds you not to leave the grill out, or the iron (Fe) in the grill will react with oxygen (O2) in the air to produce rust (Fe2O3). a. Write a balanced equation for this reaction. Be sure to show your work.

Answer 1

Answer:

Explanation:

Oxygen gas and water must be present for iron to rust.

A region of the metal’s surface serves as the anode, where oxidation

occurs:

Fe(s) → Fe²⁺ (aq) + 2 e⁻

The electrons given up by iron reduce atmospheric oxygen to water at the cathode, which is another region of the same metal’s surface:

O₂ (g) + 4H⁺ (aq) + 4 e⁻ → 2 H₂O (l)

The overall redox reaction is:

2 Fe(s) + O₂(g) → 4H⁺(aq) + 2Fe²⁺ (aq) + 2 H₂O(l)

The Fe²⁺ ions formed at the anode are further oxidized by oxygen:

4 Fe²⁺ (aq) + O₂(g) 1 (4 + 2x) H₂O (l) → 2 Fe₂O₃ . xH₂O(s) + 8 H⁺(aq)

This hydrated form of iron(III) oxide is known as rust. The amount of water associated with the iron oxide varies, so we represent the formula as 2 Fe₂O₃ . xH₂O.