Question

Iron and oxygen gas can react to form the magnetic oxide of iron Fe3O4. How many grams of Fe3O4 can be made from 13.2 g of O2?

Answer 1

1. Write and balance the equation.
3Fe + 2O2 ==> Fe3O4

2. Convert grams O2 to mols. mols = grams/molar mass = ?

3. Using the coefficients in the balanced equation, convert mols O2 to mols Fe3O4. That's ?mols O2 from step 2 x (1 mol Fe3O4/2 mols O2) = ? mols O2 x (1/2) = ?

4. Now convert mols Fe3O4 to grams. g = mols x molar mass.