def get_chemical_properties(output):
    """
    Format simulation results from "run_chemical_model".

    Parameters
    ----------
    output : tuple
        Results of function "run_chemical_model".

    Returns
    -------
    partial_pressure : float
        Sum of partial pressures [atm].
    rho_phreeqc : float
        Denisty in [kg/m**3].
    t_phreeqc : float
        Temperature in [°C]

    """
    
    # Indices / output format provided with the USER_PUNCH block in function "make_chemical_model"
    partial_pressure = sum(output[2][0:5]) # why the hell is it not 0:4 here? Whatever it works...
    partial_pressure = partial_pressure
    rho_phreeqc = output[2][5]
    t_phreeqc = output[2][6]
    
    return partial_pressure, rho_phreeqc, t_phreeqc