Question

Hemoglobin is the oxygen-transport protein in red blood cells and contains 0.340% iron
(Fe) by mass. If a blood sample is found to have 12.0 g/dL of hemoglobin, how many
iron atoms are in a human body that has 5.0 pints of this blood? Note that d stands
for the prefix deci- meaning 1/10, 1 pt = 473.176 mL, and NA = 6:022 X 10^23.

Answer 1

ok, so let's pretend that we have 100 grams of hemoglobin. By ratioof mass, we have 0.340 grams of iron. Let's use that to calculatethe number of moles of iron (and thus the number of moles ofhemoglobin)

.340g x (1mol Fe/ 55.845g) = 0.006088mol Fe

Four atoms of iron per molecule, or four moles of iron per mole ofhemoglobin molecules:

.340g x (1mol Fe/ 55.845g) x (1mol Hem / 4mol Fe) = 0.001522molHem

Given already that we have 100 grams of hemoglobin, just put gramsover moles:

100g hem / .001522mol hem = 65700g/mol

This number is ridiculously large, but for proteins, that'snormal =D