Question

A mixture of He, N₂ and Ar has a pressure of 18.7 atm at 28.0 degrees C . If the partial pressure of He is 2449 torr and that of Ar is 2775 mmHg, what is the partial pressure N₂ of ?

Answer 1

To find the partial pressure of N2, convert the given pressures of He and Ar to atm, then use Dalton's law of partial pressures to subtract the sum of He and Ar pressures from the total pressure of the gas mixture. The partial pressure of N2 is found to be approximately 11.826 atm.

Step-by-step explanation:

To find the partial pressure of N2, we first need to make sure that all pressures are in the same units. We have the pressure of the mixture as 18.7 atm, partial pressure of He as 2449 torr, and partial pressure of Ar as 2775 mmHg. Note that 1 atm = 760 torr = 760 mmHg. Therefore, we convert the pressures of He and Ar to atm:

• Pressure of He = 2449 torr × (1 atm / 760 torr)
• = 3.223 atm
• Pressure of Ar = 2775 mmHg × (1 atm / 760 mmHg)
• = 3.651 atm

Now, using Dalton's law of partial pressures, which states that the total pressure is the sum of the partial pressures of the individual gases, we can find the partial pressure of N2.

Total pressure (Ptotal) = Pressure of He + Pressure of Ar + Pressure of N2

Substituting the known pressures:

1. 18.7 atm = 3.223 atm + 3.651 atm + Pressure of N2
2. Pressure of N2 = 18.7 atm - (3.223 atm + 3.651 atm)
3. Pressure of N2 = 11.826 atm

Thus, the partial pressure of N2 in the mixture is approximately 11.826 atm.