Chemistryhard · Past Paper
Calculate the percentage of Iron in pure Magnetite (Fe3O4). (Atomic mass: Fe=56, O=16)
A70.0%
B72.4%
C75.5%
D68.2%
✓ Correct Answer: B — 72.4%
Molar mass = (3x56) + (4x16) = 168+64 = 232. %Fe = (168/232) x 100 ≈ 72.4%.
Share this question