def molality(xc, xw):
    """Calculates molality of each solute in the aqueous phase.

    Parameters
    ----------
    xc : float
        Mole fraction of component.
    xw : float
        Mole fraction water.

    Returns
    ----------
    float
        Molality of component in mol[component] / kg[water].

    """
    return xc / (xw * 0.018015)