Question

Chemical analysis show that hemoglobin contains 0.34 percent Fe by mass. What is the minimum possible molar mass of hemoglobin? The actual molar mass of hemoglobin is four times this minimum value. What conclusion can you draw from these data?

Answer 1

If hemoglobin is 0.34% Fe, that means 100 g hemoglobin contains 0.34 g Fe. The minimum molar mass will contain 1 mole Fe so 100 x (55.85/0.34) = about 16,000 but you need to do it more accurately.
If the actual molar mass is 4x that value, that means the molar mass is 4 x the empirical mass or the molecular formula is (empirical formula)₄.