The mole fraction of oxygen in air is 0.209. Assuming nitrogen is the only other constituent,
what are the partial pressures (in torr) of oxygen and nitrogen when the barometer reads 780
torr?
To determine the partial pressures of oxygen and nitrogen, we need to use the mole fraction of oxygen and the total pressure of air.
Given:
Mole fraction of oxygen (Xoxygen) = 0.209
Total pressure of air (Ptotal) = 780 torr
Step 1: Calculate the mole fraction of nitrogen.
The mole fraction of nitrogen (Xnitrogen) is equal to 1 - Xoxygen.
Xnitrogen = 1 - Xoxygen
= 1 - 0.209
= 0.791
Step 2: Calculate the partial pressure of oxygen.
The partial pressure of oxygen (Poxygen) is equal to the mole fraction of oxygen multiplied by the total pressure.
Poxygen = Xoxygen * Ptotal
= 0.209 * 780 torr
≈ 162.72 torr
Step 3: Calculate the partial pressure of nitrogen.
The partial pressure of nitrogen (Pnitrogen) is equal to the mole fraction of nitrogen multiplied by the total pressure.
Pnitrogen = Xnitrogen * Ptotal
= 0.791 * 780 torr
≈ 617.28 torr
So, the partial pressures of oxygen and nitrogen when the barometer reads 780 torr are approximately:
Partial pressure of oxygen (Poxygen) ≈ 162.72 torr
Partial pressure of nitrogen (Pnitrogen) ≈ 617.28 torr
To calculate the partial pressures of oxygen and nitrogen in air, we need to use Dalton's law of partial pressures. According to Dalton's law, the total pressure of a mixture of gases is equal to the sum of the partial pressures of each gas.
Given:
Mole fraction of oxygen (Xoxygen) = 0.209
Mole fraction of nitrogen (Xnitrogen) = 1 - Xoxygen = 1 - 0.209 = 0.791
Total pressure (Ptotal) = 780 torr
To find the partial pressure of oxygen (Poxygen), we can use the following formula:
Poxygen = Xoxygen * Ptotal
Plugging in the values:
Poxygen = 0.209 * 780 torr
Poxygen = 162.72 torr
So, the partial pressure of oxygen is 162.72 torr.
To find the partial pressure of nitrogen (Pnitrogen), we can use the same formula:
Pnitrogen = Xnitrogen * Ptotal
Plugging in the values:
Pnitrogen = 0.791 * 780 torr
Pnitrogen = 617.34 torr
So, the partial pressure of nitrogen is 617.34 torr.
XO2 = 0.209
XN2 = 1-0.209 = ?
pO2 = XO2*780 = ?
pN2 = XN2*780 = ?