Stoichiometric yield of iron from hematite (Fe₂O₃)

Steps:

• Hematite formula is Fe₂O₃; molar mass ≈160 g/mol, with 2 Fe atoms (112 g iron).
• Iron mass fraction in pure hematite = 112/160 = 0.7 (70%).
• Maximum iron from 500 kg hematite = 500 × 0.7 = 350 kg.

Why C is correct:

• 350 kg equals the theoretical yield from the Fe₂O₃ formula, where 70% by mass is iron.

Why the others are wrong:

• A: 160 kg assumes only 32% iron, ignoring Fe₂O₃ stoichiometry.
• B: 240 kg implies 48% iron, underestimating the 2:3 Fe:O ratio.
• D: 420 kg suggests 84% iron, violating conservation of mass in Fe₂O₃.

Final answer: C