Question

1. your hemoglobin contains 0.33% iron by mass. if the molar mass of hemoglobin is 68,000 g/mol, how many iron atoms are there in each molecule of hemoglobin?

Explanation:

Step1: Calculate the mass of iron in one mole of hemoglobin

The molar mass of hemoglobin is \(M = 68000\space g/mol\). Since hemoglobin contains \(0.33\%\) iron by mass, the mass of iron in one mole of hemoglobin, \(m_{Fe}\), is given by the formula \(m_{Fe}=\frac{0.33}{100}\times M\).
Substituting \(M = 68000\space g/mol\) into the formula, we get \(m_{Fe}=\frac{0.33}{100}\times68000\space g/mol = 224.4\space g/mol\).

Step2: Calculate the number of moles of iron in one mole of hemoglobin

The molar mass of iron, \(M_{Fe}=55.85\space g/mol\). The number of moles of iron, \(n_{Fe}\), in one mole of hemoglobin is calculated using the formula \(n_{Fe}=\frac{m_{Fe}}{M_{Fe}}\).
Substituting \(m_{Fe} = 224.4\space g/mol\) and \(M_{Fe}=55.85\space g/mol\) into the formula, we get \(n_{Fe}=\frac{224.4}{55.85}\approx4\space mol\).
Since one mole of any substance contains \(6.022\times 10^{23}\) atoms (Avogadro's number), and the number of moles of iron in one mole of hemoglobin is approximately \(4\space mol\), the number of iron atoms in one molecule of hemoglobin is \(4\).

Answer:

There are \(4\) iron atoms in each molecule of hemoglobin.