Question

What will be the masses of h2, o2 and n2 in a 15l gaseous mixture at 20 degree and 740 mm pressure, if the composition of the mixture by volume is h2 = 10%, o2 =20% and n2 = 70%?

Answer 1

Since inspired air is 21% oxygen and atmospheric pressure is 760 mmHg (at sea level), the partial pressure of oxygen is 0.21 x 760 mmHg = 160 mmHg. As air moves into the alveoli, water vapor and carbon dioxide are added, and that reduces the partial pressure of oxygen to about 100 mmHg in the alveolar gas.