When air is inhaled, it enters the alveoli of the lungs,

Chapter 6, Problem 74P

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Problem 74P

When air is inhaled, it enters the alveoli of the lungs, and varying amounts of the component gases exchange with dissolved gases in the blood. The resulting alveolar gas mixture is quite different from the atmospheric mixture. The following table presents selected data on the composition and partial pressure of four gases in the atmosphere and in the alveoli:

Atmosphere (sea level)	Alveoli
Gas	Mole%	Partial Pressure (torr)	Mole%	Partial Pressure (torr)
N2	78.6	–	–	569
O2	20.9	–	–	104
CO2	00.04	–	–	40
H2O	00.46	–	–	47

If the total pressure of each gas mixture is 1.00 atm, calculate:

(a)  The partial pressure (in torr) of each gas in the atmosphere

(b)  The mole % of each gas in the alveoli

(c)  The number of O2 molecules in 0.50 L of alveolar air (volume of an average breath of a person at rest) at 37°C