Answer:
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
Explanation:
