3 Answers

Using the Ideal Gas Equation
PV = nRT
V = nRT/P
Where
n = moles(He) = 1000g / 4 = 250 moles
R = Gas Constant 8.413.
T = temperature in Kelvvin K (5 + 273 = 278
P = pressure in Pascals(Pa) 98,19213 Pa
Hence
V = 250 x 8.314 x 278 / 98192
V = 5.88 m^3 ( NOT dm^3 nor cm^3, but cubic metres).

Ideal gas equation problem ….
PV = nRT ……………. ideal gas equation
PV = mRT / M ……… n=m/M … m=mass, M=molar mass
V = mRT / (PM) ……. solve for V
V = 1000g x 62.36Ltorr/molK x 278.15K / 735 torr / 4.00 g/mol
V = 5.90×10^3 L ……. to three significant digits

1Kg == 1000/4 = 250 moles
V = nRT/P = (250)(62.4)(278)/735
V = 5900 L