what is the mass of a gas that has 48.9liters a pressure of 724torr 25 degrees C and molecular weight of 345g?

Question

what is the mass of a gas that has 48.9liters a pressure of 724torr 25 degrees C and molecular weight of 345g/ mole?

Answer 1

number of moles n= pV/RT
in MKSA
R=8.314 , T = 25+273=298, V =48.9*10^-3m^3, 724torrs = 724*133.3Pa=96510Pa

n= 0.0489*96510/(8.314*298) =1.90mole
and the mss is 1.9*345=657g

Answer 2

Assuming ideal behavior (since you have no a or b values):

PV=nRT

(724/760 atm)(48.9 L) = n(0.08206 L*atm/mol*K)(298 K)

Solve for n and multiply by 345 g/mol for mass.