An oxygen enrichment device is needed for people with impaired respiratory systems. To design such a device, it is necessary to compute the work needed to produce a stream that contains 50 mol % of oxygen from air (21 mol % oxygen) at 300 K and 1 bar. If the exit streams are at the same temperature and pressure as the inlet air, and half of the oxygen in the air is recovered in the enriched oxygen stream, what is the minimum amount of work required to operate whatever device is developed for this process?