Question

Hydrogen is generated by passing hot steam over iron, which oxidizes to form Fe3O4 in the following equation.
3Fe(s) + 4H2O(g) -> 4H2(g) + Fe3O4(s)
Atomic Mass Fe = 55.85 g/mol
Molar Mass Fe3O4 = 231.55 g/mol
Molar Mass H2 = 2.02 g/mol
Molar Mass H2O = 18.02 g/mol
a. If 625 g of Fe3O4 is produced in the reaction, how many moles of hydrogen are produced at the same time?
b. How many atoms of iron would be needed to generate 27 g of hydrogen?

Answer 1

a. If 625 g of Fe3O4 is produced in the reaction, how many moles of
hydrogen are produced at the same time?

<b><i> mols Fe3O4 = g/molar mass = 625/231.55= approx 2.7
mols H2 produced = 2.7 x (4 mols H2/1 mol Fe3O4) = 2.7 x 4/1 = ?</b></i>

b. How many atoms of iron would be needed to generate 27 g of hydrogen?
27 g H2 = 27/2 = 13.5 mols H2
mols Fe = 13.5 mols H2 x (3 mols Fe/4 mols H2) = 13.5 x 3/4 = approx 10.1 Then you know there are 6.02E23 atoms in a mol of anythng. I'll leave that for you.
Post your work if you have further questions.

Answer 2

9.6 mol h2