A mixture of He , N2 , and Ar has a pressure of 12.0 atm at 28.0 °C. If the partial pressure of He is 2381 torr and that of Ar is 2249 mm Hg, what is the partial pressure of N2 ?

Answer 1

The total pressure is the sum of the partial pressures of each gas

P_T = P_He + P_N2 + P_Ar

Let's first convert all pressures to the same unit, say, atmospheres.

P_He = 2381 torr x 1 atm/760 torr = 3.13 atm

P_N2 = X

P_Ar = 2249 mm Hg x 1 atm/760 mm Hg = 2.96 atm

P_T = 12.0 atm

P_T =12.0 atm = 3.13 atm + X atm + 2.96 atm

X = P_N2 = 12.0 - 3.13 - 2.96

P_N2 = 5.91 atm