Question

The molar mass of hemoglobin is about 65000 g/mol. Hemoglobin contains 0.35%Fe by mass. Thus, iron atoms present in hemoglobin molecules are _______.

Answer 1

Hint: We know that hemoglobin is a protein found in red blood cells. Iron is an essential element for blood production. In our body most of the iron is found in hemoglobin and in muscle cells called myoglobin.

Step by step solution:
Hemoglobin carries oxygen efficiently from the lungs to the tissues in the body. It also aids in transporting hydrogen ions and carbon dioxide back to the lungs. Iron is an essential element for blood production. About 70% of our body’s iron is found in red blood cells of our blood and in muscle cells. From the given data we can find that:
Mass of Fe in hemoglobin = 0.35% of molar mass of hemoglobin
                     = 0.35% of 65000
                     = (0.35 x 65000) / 100
                     = 227.50 g/mol
Now, we know that molecular mass of iron (Fe) = 55.85 g/mol
So, the number of moles of iron in 1 mole of hemoglobin = mass of iron in hemoglobin / molecular mass of iron.
                                   = 227.50/55.85
                                   = 4.07, which is approximately equal to ‘4’
Correspondingly 1 molecule of hemoglobin contains 4 atoms of Fe.
So, the correct answer is “4”.

Note: The given data of hemoglobin weight and %weight of iron will change by some minute amount in mass and weight %. And the chemical formula of hemoglobin is$$C_{2952}{H}_{4664}{O}_{832}{N}_{812}{S}_{8}F{e}_4$$.