A $0\mathrm{.}2-$m$3$ tank containing helium at $15$ bar and $22$C

will be used to supply $4\mathrm{.}5$ moles per minute of helium

at atmospheric pressure using a controlled adiabatic

throttling valve.

a$.$ If the tank is well insulated, what will be the pressure

in the tank and the temperature of the gas stream

leaving the throttling valve at any later time t$?$

b$.$ If the tank is isothermal, what will be the pressure

in the tank as a function of time?

You may assume helium to be an ideal gas with C$$P $=22$ J$/($mol K$),$ and that there is no heat transfer between the tank and the gas.