Problem 1. Producing oxygen-enriched air for people with emphysema When a person has emphysema, the inner walls of the air sacs in the lungs weaken and eventually rupture - creating one large air space instead of many small ones. This reduces the surface area of the lungs and, in turn, the amount of oxygen that reaches the bloodstream. For patients with severe emphysema, oxygen-enriched air is provided to help relieve the symptoms. Consider the case where oxygen-enriched air is made by adding pure oxygen at atmospheric pressure (101kPa) to ordinary air ( 21 mole\% oxygen, 79% mole nitrogen). A mixing chamber blends the two streams to produce a mixture with 35 mole \% oxygen at a rate of 0.7 moles of mixture/minute. Flowchart (not completely labeled) a) Draw a completely labeled flowchart of the process. (Hint: Redraw by hand and complete the one above) b) What is the maximum number of independent material balances that can be written for this process? c) Do a degree-of-freedom analysis for the problem. d) How many moles of pure oxygen gas must be added to each mole of air? ( Ans: moles O2/ mole air =0.215 moles O2 /mole air)