Question

Hemoglobin contains 0.25 % iron by mass. The molecular mass of hemoglobin is 89600. Calculate the number of iron atoms per molecule of hemoglobin [Atomic mass of Fe =56].
A. 4
B. 5
C. 6
D. 2

Answer 1

Hint: By using the method of mole concept. We can calculate the given data and find the number of atoms present in the molecule of hemoglobin.

Complete step by step answer:
In the given question,
Amount of iron in % = 0.25 %
Molecular mass of hemoglobin is 0.25% mass of iron atom
It means only the out of 100 % mass of hemoglobin, only 0.25 % consists of iron. So, with the help of mass percent formula, molecular mass of iron present in hemoglobin is
\[ = 89600 \times 0.0025\]............. (because 0.25 % = $\dfrac{0.25}{100}$)
$ = 224$
Now, the mass of atom iron atom $ = 56$
So, No. of atoms $ = \dfrac{224}{{56}}$
$ = 4$ atoms
So, one molecule of hemoglobin contains 4 atoms of iron.

So, the correct answer is “Option A”.

Additional Information: Hemoglobin is a protein in red blood cells that carries oxygen from lungs to different organs of the body and transports carbon dioxide from different organs to lungs.
Lower levels of hemoglobin than the normal level mean low red blood cell count, which leads to anemia. Higher levels of hemoglobin is not considered good either.

Note: Interpretation of such questions is very important. You need to understand what exactly is asked and what exactly is given in the question. In this particular question, understanding the meaning of “Hemoglobin contains 0.25 % iron by mass” was extremely important to get the correct answer.