6.6 Nitric oxide (NO) is an extremely potent vasodilator that is used to treat newborns who have pulmonary hypertension and adults who have undergone certain operative procedures. We want to examine the transport of the gas through an alveolus and into the capillaries. The gas is added at a concentration of less than 100 parts per million (ppm). The alveolus is modeled as a sphere of radius Ra (see Figure 6.29). FIGURE 6.29 Diffusion in an alveolus. Determine the mole fraction of the gas and assess the maximum error in the flux, assuming that the gas is a dilute solution of NO. In each inspiration, the concentration of NO in each alveolus is 30ppm and the gas is initially uniformly mixed. Is the gas completely removed between breaths? Use the following data: alveolus radius =50mDNO=0.2cm2s1 gas concentration in blood =0