def _calculate_total_mass_(elemental_array):
    """
    Sums the total weight from all the element dictionaries in the elemental_array after each weight has been added (after _add_ideal_atomic_weights_())

    :param elemental_array: an array of dictionaries containing information about the elements in the system
    :return: the total weight of the system
    """
    return sum(a["weight"] for a in elemental_array)