If I have the equation 2Fe + 3Cl2 → 2 FeCl3, how many of the iron molecules will I need to match 9 of the chlorine molecules on the reactant side?

Question

and  Using the same equation (and 9 chlorine molecules) as above, how many Iron (III) chloride (FeCl3) molecules can I create?

Answer 1

Since 2 iron molecules combine with 3 chlorine (assuming they are counting Cl2 molecules rather than individual Cl atoms), you would need 6 (2*3) iron molecules for the reaction and create 6 (2*3) FeCl3 molecules.