how would you find the solution?

Question

A mixture of He, N2, and Ar has a pressure of 21.0 atm at 28.0 °C. If the partial pressure of He is 2427 torr and that of Ar is 1787 mm Hg, what is the partial pressure of N2?



𝑃N2=

Answer 1

Daltons law of partial pressures.

The total pressure is equal to the sum of the partial pressures of all the gases present.

In this problem, we have different units of pressure. We have a total P of 21.0 atmospheres.

We have 2427 torr for He and we have 1787 mm Hg for Ar. We will convert all of them to atmospheres.

P_total = 21.0 atm

P_He = 2427 torr x 1 atm / 760 torr = 3.19 atm

P_Ar = 1787 mm Hg x 1 atm / 760 mm Hg = 2.35 atm

P_N2 = ?

Daltons law: P_total = P_He + P_Ar + P_N2

21.0 = 3.19 + 2.35 + P_N2

P_N2 = 15.5 atm