If you start with 4 moles of iron and 3 moles of oxygen to produce iron oxide, what is the limiting reagent? (you will need to balance the equation first.) fe + o2 -> fe2o3

No limiting reagent. There is an exact amount  of each.

Explanation:

Start by getting the equation

Fe + O2 -> Fe2O3

If you balance the oxygens the Fe will easily follow.

Fe + 3O2 => 2Fe2O3

So far what you have is 6 oxygens on the right and 6 on the left. Now all you need do is balance the irons. The are 4 on the right (2Fe2). So you must have 4 on the left.

4Fe + 3O2 -> 2Fe2O3

Now to your question if you have 4 mols of iron, you need 3 mols of O2. Those are the balance numbers of the equation. They also represent mols.

There is no limiting reagent in the theoretical world of chemistry. All the iron will be used up and so will the given amount of oxygen.

c most likely

hop this let me know if it is wrong

answer: - 3.) the oxidation state of nitrogen in no changes from +2 to 0, and the oxidation state of carbon in co changes from +2 to +4 as the reaction proceeds.

solution: - as per the rules, oxidation number of oxygen in its compounds is -2. the sum of oxidation numbers of all the elements of a molecule or compound is zero.

also, the oxidation number in elemental form is zero.

in no, the oxidation number of o is -2 so the oxidation number of n is +2 so that the sum is zero.

similarly, the oxidation number of c in co is +2 and o is -2.

on product side the oxidation number of n is 0 as it is in the elemental form() .

oxidation number of c in carbon dioxide is +4 as there are two oxygen in it and we know that each oxygen is -2.

so, oxidation number of n is changing from +2 to 0 and the oxidation number of c is changing from +2 to +4.

since nitrogen is reduced and hence no is acting as an oxidizing agent. carbon is oxidized and so co is acting as a reducing agent.

so, the right choice is number 3.)the oxidation state of nitrogen in no changes from +2 to 0, and the oxidation state of carbon in co changes from +2 to +4 as the reaction proceeds.