PV=nRT
P = 85.0 x 10^3 Pa
T = 273 + 20 = 293 K
n = 2.0 moles
R = 8.314 m3. pa / mol .K
V = 2.0 x 293 x 8.314 / 85.0x10^3 = 0.195623529 m^3
The mass of He gas = 21.428 g
<h3>Further explanation</h3>
Given
120 liters of He gas
Required
the mass in grams
Solution
Conditions at T 0 ° C and P 1 atm are stated by STP (Standard Temperature and Pressure). At STP, Vm is 22.4 liters/mol.
Mol for 120 L :

Mass of He gas(MW=4 g/mol) :
