@property<EOL><INDENT>def isentropic_exponent(self):<DEDENT>
Cp, Cv = self.Cpg, self.Cvg<EOL>if all((Cp, Cv)):<EOL><INDENT>return isentropic_exponent(Cp, Cv)<EOL><DEDENT>return None<EOL>
r'''Gas-phase ideal-gas isentropic exponent of the chemical at its
        current temperature, [dimensionless]. Does not include
        pressure-compensation from an equation of state.

        Examples
        --------
        >>> Chemical('hydrogen').isentropic_exponent
        1.405237786321222