How many grams of Fe2O3 will be produced from 24 g of Fe and 5g of O2

Answer 1

Write the balanced equation for the reaction taking place:

4Fe + 3O₂ ==> 2Fe₂O₃ (rust)

Use the stoichiometry of the balanced equation and dimensional analysis to find limiting reagent & grams of Fe₂O₃:

24 g Fe x 1 mol Fe/55.85 g x 2 mol Fe₂O₃/4 mol Fe x 160 g/mol Fe₂O₃ = 34 g Fe₂O₃ (2 sig. figs.)

5 g O₂ x 1 mol O₂/32 g x 2 mol Fe₂O₃/3 mol O₂ x 160 g/mol Fe₂O₃ = 17 g Fe₂O₃ (2 sig. figs.)

Since less Fe₂O₃ is formed from O₂, the O₂ is limiting and the answer is 17 g Fe₂O₃ will be formed.