A rewrite of "The first thermodynamics in the world with regard to hemoglobin (5)." The transfer of oxygen molecules from (2)oxyhemoglobinA to (3)deoxyhomoglobinF. A means Adult including mother and F means Fetus. I'll explain that the transfer of oxygen molecules from mother to fetus is a spontaneous process. The pH value of human blood is 6.8~7.8, the pKa value of (4)deoxyhomoglobinA is 8.2, th