Stoichiometric calculations
1. Ferrous oxide on heating in air converts to ferric oxide. What mass of ferric oxide will be produced by
heating 5 g of ferrous oxide in air?
111.1g)
Answers
Answer:
Ferrous oxide on heating in air converts to ferric oxide. Mass of ferric oxide produced by heating 5 g of ferrous oxide in air is 5.56 g
Explanation:
The equation for the reaction of heating ferrous oxide in to form ferric acid
4FeO + O₂ = 2Fe₂O₃
Calculate the moles of 5g Ferrous oxide using gram formula mass
Moles = mass / molar mass
molar mass of FeO = 56 + 16 = 72
Moles = 5g / 72gmol⁻¹
= 0.0694 moles
Use the mole ratio in the equation to find the moles of 2Fe₂O₃
Mole ratio FeO : Fe₂O₃ = 4:2 = 2:1
Moles of FeO = 0.06944 moles
Moles of Fe₂O₃ = 0.0694 / 2 = 0.03472 moles
Use the gram formula mass to calculate the mass of Fe₂O₃
Molar mass of Fe₂O₃ = (56 × 2) + (16 × 3) = 112 + 48 = 160 g/mol
Mass = moles × molar mass
Mass = 0.03472 moles × 160 gmol⁻¹
Mass = 5.5552
The mass of Fe₂O₃ produced is 5.56 g