In air at 1 ata, what is the partial pressure of nitrogen and oxygen?

To understand the partial pressures of nitrogen and oxygen in air at 1 atmosphere absolute (ata), it's essential to know the composition of air. Air is made up of approximately 21% oxygen and 79% nitrogen by volume.

When determining the partial pressures, you apply Dalton's Law of Partial Pressures, which states that the total pressure of a gas mixture is equal to the sum of the partial pressures of the individual gases. In this case, at 1 ata, the partial pressure of a gas can be calculated by multiplying the fractional concentration of that gas by the total pressure.

For oxygen:

• The concentration is 21%, or 0.21 of the total pressure.

• Therefore, the partial pressure of oxygen at 1 ata is 1 ata * 0.21 = 0.21 ata.

For nitrogen:

• The concentration is 79%, or 0.79 of the total pressure.

• Hence, the partial pressure of nitrogen at 1 ata is 1 ata * 0.79 = 0.79 ata.

Thus, the partial pressures of nitrogen and oxygen under these conditions are 0.79 ata for nitrogen and 0.21 ata for oxygen. The correct representation of this relationship is