Question

Hemoglobin, an iron-containing oxygen-transport protein, is 0.349% Fe by mass.

If a hemoglobin molecule contains four iron atoms, what is the molar mass (in g/mol) of hemoglobin?

Answer 1

Answer : The molar mass of hemoglobin is,
`6.40* 10^4g/mol`

Explanation : Given,

Molar mass of iron = 55.85 g/mol

0.349 % Fe by mass that means 0.349 grams of Fe present in 100 grams of hemoglobin.

or,

`\text{Percent of Fe}=\frac{4* \text{Molar mass of Fe}}{\text{molar mass of hemoglobin}}* 100`

Now put all the given values in this formula, we get:

`0.349=\frac{4* 55.85g/mol}{\text{molar mass of hemoglobin}}* 100`

`\text{molar mass of hemoglobin}=64011.46g/mol=6.40* 10^4g/mol`

Thus, the molar mass of hemoglobin is,
`6.40* 10^4g/mol`