Question

4 Fe + 3 O2 = 2 Fe2O3 a) Determine the number of moles of iron oxide produced from 7.5 moles of oxygen. Answer 2 significant digitsb) Determine the number of moles of Iron required to react with 4.5 moles of oxygen. Answer 2 significant digits

Answer 1

4 Fe + 3 O₂ ----> 2 Fe₂O₃

We can read that reaction like a recipe, where the coefficients of the equation are the quantities of the recipe. The reaction says: when 4 moles of Fe reacts with 3 moles of O₂, 2 moles of Fe₂O₃ are produced.

a) According to the reaction, 3 moles of O₂ produces 2 moles of Fe₂O₃. We will use that relationship to find the moles of Fe₂O₃ that are produced from 7.5 moles of O₂.

7.5 moles of O₂ * 2 moles of Fe₂O₃ / (3 moles of O₂) = 5.0 moles of Fe₂O₃

Answer: 5.0 moles of Fe₂O₃ are produced from 7.5 moles of oxygen.

b) According to the reaction, 4 moles of Fe will react with 3 moles of O₂. Let's use that relationship to find the moles of Fe required to react with 4.5 moles of O₂.

4.5 moles of O₂ * 4 moles of Fe/(3 moles of O₂) = 6.0 moles of Fe

Answer: 6.0 moles of Fe are required to react with 4.5 moles of oxygen.