The presence of hemoglobin in normal aerial blood increases its oxygen concentration approximately how many times?

Normal aerial blood has a PO2 of about 100 mm Hg. The concentration of oxygen in the absence of hemoglobin is the dissolved oxygen, which is 100 x 0.003, or 0.3 ml O2/100 ml blood. However, normal aerial blood contains about 15 g/100 ml of hemoglobin, and each gram can combine with 1.39 ml O2. Since the oxygen saturation of normal aerial blood is about 97%, the total oxygen concentration is given by (1.39 x 15 x 97/100) + 0.3 ml O2/100 ml blood. This is about 20.5 as opposed to the dissolved oxygen concentration of 0.3 ml O2/100 ml blood. Therefore, the presence of hemoglobin increases the oxygen concentration about 70 times