The essential respiratory bio-macromolecule Haemoglobin is analyzed and found to contain exactly iro — Mole Concept and Some Basic Concepts of Chemistry Chemistry Question
Question
The essential respiratory bio-macromolecule Haemoglobin is analyzed and found to contain exactly $0.25\%$ iron ($Fe$) by weight. If the highly precise molecular weight of Haemoglobin is evaluated to be $89600\text{ g/mol}$, calculate the exact integer number of Iron atoms present in a single functional molecule of Haemoglobin. (Atomic weight of $Fe = 56$).
💡 Solution & Explanation
Step 1: Calculate the total mass of Iron in one mole of Haemoglobin. Mass of Iron = $0.25\%$ of $89600\text{ g}$. Mass of Iron = $\left(\frac{0.25}{100}\right) \times 89600 = \left(\frac{1}{400}\right) \times 89600 = 224\text{ g}$. Step 2: Determine the number of Iron atoms per molecule. Since 1 mole of Haemoglobin contains $224\text{ g}$ of Iron, we divide this by the atomic mass of a single mole of Iron atoms ($56\text{ g/mol}$) to find the molar ratio. Number of Fe atoms = $\frac{224\text{ g}}{56\text{ g/mol}} = 4$. Therefore, there are exactly 4 Iron atoms in each molecule.