helium gas of base the equation of state PV equals to RT $-$ A $/$ T into P $+$ b $+$ equals to $386\mathrm{.}7$ B equals to $15\mathrm{.}29$ CP equals to $18\mathrm{.}9+0\mathrm{.}055$ t estimate the change in entropy and enthalpy for helium is changes from $5$to $15$ bars at $300$ Kelvin and $300$ K to $500$ k at $5$ bars