Moles of gas=19.75
Further explanation
The gas equation can be written
[tex]\large {\boxed {\bold {PV = nRT}}}[/tex]
where
P = pressure, atm
V = volume, liter
n = number of moles
R = gas constant = 0.08206 L.atm / mol K
T = temperature, Kelvin
V=150 L
P=4.2 atm
T=389 K
[tex]\tt n=\dfrac{PV}{RT}\\\\n=\dfrac{4.2\times 150}{0.082\times 389}\\\\n=19.75[/tex]
