vapor pressure of water at 20 c kpa is 2.3388.
vapor pressure of water at 20 c kpa is 2.3388.
vapor pressure of water at 20 c kpa?
2.3388
Na
Na
there is, however, a complication that increases the volume of air that needs to be inhaled per minute (respiratory minute volume) to provide the same amount of oxygen to the lungs at altitude as at sea level. during inhalation the air is warmed and saturated with water vapor during its passage through the nose passages and pharynx. saturated water vapor pressure is dependent only on temperature. at a body core temperature of 37 °c it is 6.3 kpa (47.0 mmhg), irrespective of any other influences, including altitude. thus at sea level, where the ambient atmospheric pressure is about 100 kpa, the moistened air that flows into the lungs from the trachea consists of water vapor (6.3 kpa), nitrogen (74.0 kpa), oxygen (19.7 kpa) and trace amounts of carbon dioxide and other gases (a total of 100 kpa). in dry air the partial pressure of o at sea level is 21.0 kpa (i.e. 21% of 100 kpa), compared to the 19.7 kpa of oxygen entering the alveolar air. (the tracheal partial pressure of oxygen is 21% of [100 kpa – 6.3 kpa] = 19.7 kpa). at the summit of mt. everest (at an altitude of 8,848 m or 29,029 ft) the total atmospheric pressure is 33.7 kpa, of which 7.1 kpa (or 21%) is oxygen. the air entering the lungs also has a total pressure of 33.7 kpa, of which 6.3 kpa is, unavoidably, water vapor (as it is at sea level). this reduces the partial pressure of oxygen entering the alveoli to 5.8 kpa (or 21% of [33.7 kpa – 6.3 kpa] = 5.8 kpa). the reduction in the partial pressure of oxygen in the inhaled air is therefore substantially greater than the reduction of the total atmospheric pressure at altitude would suggest (on mt everest: 5.8 kpa "vs." 7.1 kpa).
respiratory system