In a gaseous mixture of a #2.0*L# volume, at #755*"mm Hg"#, and a temperature of #346*K#, #P_"dinitrogen"=355*mm*Hg#. What are the molar quantities of helium and dinitrogen?

1 Answer
May 8, 2017

Answer:

#"Dalton's Law of Partial Pressures tells us that........."#, I get approx. #150*mg# of helium............

Explanation:

#"In a gaseous mixture, the pressure exerted by a component gas"#
#"is the same as the pressure if it ALONE occupied the container."#

#"The total pressure is the sum of the individual partial pressures."#

And this #P_"mixture"=P_"He"+P_("N"_2)#

And so #P_"He"=(755-355)*mm*Hg=400*mm*Hg#.

Given that we now #P_"He"# we can calculate its equivalent mass by means of the Ideal Gas Equation.......

#n=(PV)/(RT)=((400*mm*Hg)/(760*mm*Hg*atm^-1)xx2.0*L)/(0.0821*(L*atm)/(K*mol)xx346*K)=0.0371*mol#.

Which represents a mass of #0.0371*molxx4.0*g*mol^-1# with respect to helium gas.