def calDensityIG(MW, CoSp):
    """ 
    calculate: density of ideal gas (IG) [kg/m^3]
    args:
        MW: molecular weight [kg/mol]
        CoSp: concentration species [mol/m^3]
    """
    try:
        # density
        den = MW*CoSp
        return den
    except Exception as e:
        pass