The number of moles of gas in the sample of chlorine gas is calculated by use of ideal gas equation
that is PV=nRT
n=number of moles
R= gas constant ( 62.36367 l.torr/k.mol)
P=pressure
V=volume
from ideal gas equation n= PV/RT
n= (328 x5.0)/ ( 62.36367 x310)= 0.085 moles