A massive hemoglobin molecule contains exactly $0.25\%$ of elemental iron by weight. If the experime

Question

A massive hemoglobin molecule contains exactly $0.25\%$ of elemental iron by weight. If the experimentally determined molecular weight of this hemoglobin is $89600 \mathrm{~g/mol}$, the exact number of iron atoms present in a single molecule of it is (Atomic weight of Fe is $56 \mathrm{~u}$)

Professor PC Thomas Classes · Answer

(a) : The total mass contribution of iron within one single molecule of hemoglobin can be found by calculating $0.25\%$ of its molecular weight. Mass of iron = $\frac{89600 	imes 0.25}{100} = 224 \mathrm{~u}$. Since the atomic weight of a single iron (Fe) atom is $56 \mathrm{~u}$, the number of iron atoms present is simply the total iron mass divided by the atomic mass: $\frac{224}{56} = 4$ atoms.