Answer: To calculate the partial pressure of nitrogen in the low-pressure system, we need to use Dalton’s law of partial pressures. According to this law, the total pressure of a mixture of gases is equal to the sum of the partial pressures of the individual gases in the mixture.
In this case, we know that the atmospheric pressure is 691 mmHg. We also know that 78.0% of dry air is nitrogen. Therefore, nitrogen makes up 78.0% of the total pressure.
To calculate the partial pressure of nitrogen, we can multiply the atmospheric pressure by the fraction of nitrogen in dry air:
Partial pressure of nitrogen = Atmospheric pressure x Fraction of nitrogen in dry air Partial pressure of nitrogen = 691 mmHg x 0.78 Partial pressure of nitrogen = 539.58 mmHg
Therefore, the partial pressure of nitrogen in this low-pressure system is 539.58 mmHg.