What is the molar mass of a gas that at #823*K# exerts a pressure of #31.89*kPa# in a volume of #56.0*mL#?

1 Answer
Sep 18, 2017

Answer:

Approx.....#120*g*mol^-1#

Explanation:

We use the Ideal Gas equation, and solve for molar mass.....

#n=(PV)/(RT)=((31.89*kPa)/(101.3*kPa*atm^-1)xx56.0xx10^-3L)/(0.0821*(L*atm)/(K*mol)xx823*K)=2.61xx10^-4*mol#

And thus #"molar mass"="Mass of gas"/"Number of moles"#

#=(3.243xx10^-2*g)/(2.61xx10^-4*mol)=124.3*g*mol^-1#.

And note that this molar mass is consistent with a #P_4# molecule.....