Write the balanced equation for the rusting of iron in which iron reacts with oxygen to form iron(III) oxide. Phases are optional.

Question

Write the balanced equation for the rusting of iron in which iron reacts with oxygen to form iron(III) oxide. Phases are optional.

Answer 1

I would like to add to J.R.S.'s answer by providing an explanation of how I would approach and explain this problem to you:

1.) First thing to recognize is that it requires you to know the molecular formula for Iron(III) Oxide, which is Fe₂O₃. If you don't know this formula in all textbooks there is a page that has it and other compounds listed. I would encourage you to review this page and memorize the other compounds as these compounds will come up in future questions.

2.) Now we will write an unbalanced equation, keeping in mind that molecular oxygen( O₂) is used:

Fe + O₂ ==> Fe₂O₃

3.) In balancing problems, I like to always start with Oxygen. Because there are 2 oxygen atoms on the reactant side and three on the product side and we know that both of these numbers go into 6, we will use this to balance the oxygen. We will put a e in front of the molecular Oxygen and a 2 in front of the iron(III) oxide. This will balance the oxygens.

Fe + 3O₂ ==> 2Fe₂O₃

However, notice now that the iron is still out of balance, This can be easily solved by having a 4 in front of the iron. Now everything is balanced!

4Fe + 3O₂ ==> 2Fe₂O₃

Answer 2

The balanced equation for rusting of iron would be....

4Fe + 3O₂ ==> 2Fe₂O₃