Question

A helium gas cylinder of the sort used to fill balloons has a volume of 150 L and a pressure of 2200 psi (150 atm) at 25 ∘C

How many moles of helium are in the tank?

How many grams of helium are in the tank?

Answer 1

volume = 150 L

pressure = 150 atm

temperature = 298 K

P V = n R T

150 x 150 = n x 0.0821 x 298

n = 919.7

moles of helium = 919.7

mass of helium = moles x molar mass

                          = 919.7 x 4

                           = 3678.6 g

mass of helium =3678.6 g