Question

Iron(III) oxide is formed when iron combines with oxygen in the air. How many grams of Fe2O3 are formed when 1.47 g of Fe reacts completely with oxygen?

Answer 1

Answer:

2.10 g

Explanation:

Write the unbalanced reaction:

Fe + O₂ → Fe₂O₃

Balance it:

4Fe + 3O₂ → 2Fe₂O₃

Now use stoichiometry.  Convert mass of Fe to moles of Fe:

1.47 g Fe × (1 mol Fe / 55.8 g Fe) = 0.0263 mol Fe

Convert moles of Fe to moles of Fe₂O₃:

0.0263 mol Fe × (2 mol Fe₂O₃ / 4 mol Fe) = 0.0132 mol Fe₂O₃

Finally, convert moles of Fe₂O₃ to mass of Fe₂O₃:

0.0132 mol Fe₂O₃ × (159.7 g Fe₂O₃ / mol Fe₂O₃) = 2.10 g Fe₂O₃