Final answer:
Dry air is primarily composed of approximately 78% nitrogen, 21% oxygen, 1% argon, and trace amounts of other gases, with partial pressures calculated by applying the gas's percentage to the total atmospheric pressure.
Step-by-step explanation:
The approximate proportions of the four main components of dry air are 78% nitrogen (N₂), 21% oxygen (O₂), and 1% argon (Ar), with trace amounts of other gases like carbon dioxide (CO₂) and water vapor (H₂O). To calculate the partial pressure of any gas in this mixture, the formula P = (Patm) X (percent content in mixture) can be used. Patm, the atmospheric pressure, is the sum of all of the partial pressures of the atmospheric gases added together.
The approximate proportions of the four main components of dry air are:
Nitrogen: 78%
Oxygen: 21%
Argon: 1%
Trace amounts of other gases
These proportions have been determined through extensive scientific analysis of the Earth's atmosphere.