Answer: 1:3
Explanation:
1) To state the mole ratio of a product and a reactant we need the chemical equation that shows the reaction.
2) In the case of Fe3O4 and Fe, the chemical equation is:
Fe+H2O → Fe3O4+H2.
3) Now, you balance the equation, which will give you the coefficients of each reactant and product of the chemical reaction:
3Fe+4H2O → Fe3O4+4H2
4) From that the mole ratios are:
3 mol Fe : 4 mol 4H2O : 1 mol Fe3O4 : 4 mol H2.
5) The question requires you to find the mole ratio for Fe3O4 to Fe. Tha is:
1 mole Fe3O4 : 3 mole Fe
So, the answer is 1:3
