Question

P (atm) B V 2 10 20 30 40 V(L)

a) Ten liters of ideal air undergoes the "B" path (see P-V diagram). Starting from 1 atm and 300 K, the air is pressurized isochorically to 3 atm. Then it follows the curved paths of the "B", expanding to a maximum of 20 L before returning to the original volume at 2 atm, and then expanding once more to 20 L before returning to the original volume at 1 atm. Each curved path is half of an ellipse on a P-V diagram. Find ΔU, Q, and W for the whole process. (The area of an ellipse is πab, where a and b are half the lengths of the major and minor axes.)

b) Thirty liters of ideal air undergoes the "U" path. Starting from 3 atm and 300 K, the air expands to 35 L while the pressure drops to 1 atm, and then expands to 40 L while the pressure returns to 3 atm. The curved path is half of an ellipse. Calculate Q

Answer 1

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1370