function that returns the vaporPressure given the temperature
function vaporPressure_pTX input Modelica.SIunits.AbsolutePressure p "Pressure"; input Modelica.SIunits.Temperature T "Temperature"; input Modelica.SIunits.MassFraction[:] X "Mass fractions of composition"; output Modelica.SIunits.AbsolutePressure pVap "Vapor pressure"; end vaporPressure_pTX;