# A container holds three gases: helium, argon, and xenon. The partial pressures are 0.450 atm helium and 0.350 atm argon. The total pressure is 3.00 atm. What is the partial pressure of xenon?

Dec 1, 2014

The sum of the partial pressures is equal to the total pressure. $\text{P"_"total}$ = ${\text{P}}_{1}$ + ${\text{P}}_{2}$ + ${\text{P}}_{3}$... .To calculate the partial pressure of one of the components of a mixture, subtract the sum of known partial pressures of the other components from the total pressure.

Given/Known:

$\text{P"_"He}$ = 0.450atm

$\text{P"_"Ar}$ = 0.350atm

$\text{P"_"total}$ = 3.00 atm

Unknown:
$\text{P"_"Xe}$

Solution: Determine the sum of the partial pressures of helium and argon, then subtract the sum from the total pressure.

The sum of the partial pressures of He and Ar = 0.800atm.

$\text{P"_"Xe}$ = 3.00atm - 0.800 = 2.20atm

Dec 1, 2014

partial pressure = total pressure x mole fraction

for He: mole fraction(A)= 0.45/3=0.15atm
for Ar: mole fraction (B)=0.35/3=0.117atm

sum of mole fractions =1
(C)=1-(0.15+0.117)

partial pressure of Xe= 3 x C
=2.199 atm