Question

How many joules of net work does this person's lung do during one complete breath? Express your answer to three significant figures and include the appropriate units Constants Work Done by the Lungs. The graph (Figure 1) shows a pv diagram of the air in a human lung when a person is Inhaling and then esthaling a deep breath Such graphs, obtained in clnical practice, are normally somewhat curved, but we have modeled one as a set of straight lines of the same general shape (important The pressure shown is the gauge pressure, not the absolute pressure) Wa 495 mol Submit Figure 1 of1 X Incorrect; Try Again; 4 attempts remaining pmm of Hg) 12.0 Part B 10.0 8.0 6.0 4.0 2.0 The process ilustrated here is somewhat different from those we have been studying, because the pressure change is due to changes in the amount of gas in the lung not to temperature changes (Think of your own breathing Your lungs do not expand because they've getten hot ) w emperature ofthe ak inthe hang remains a reasonable 20°C what is the macinum number af moles in this person's hangduring·breath? Express your answer to two significant figures and include the appropriate units Ext V(L) 0.5 36 O Type here to search

Answer 1

Part A

work done = area enclosed in PV graph

just count the number of squares

each square is 1 mmHg * 0.1 L

where, 1 L = 1e-3 m³

1 mmHg = 133.3 pA

work done = 7.5 * 133.3 * 1e-3

work done = 1 J

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Part B

Notice the maximum pressure, ( on the right hand , upper end of pV curve)

p = 11 mmHg

so,

total pressure = 760 + 11 = 771 mmHg

and

v = 1.4 L ( on the right hand , upper end of pV curve)

so,

n = PV / RT

n = 771 * 133.3 * 1.4e-3 / 8.314 * (20 + 273)

n = 0.059 mol