 #1
ewang
 4
 0
 Homework Statement:
 Find the work done by the gas (or on the gas) for an adiabatic process starting at V = 0.024 m^3 and 101325 Pa and ending at 0.0082 m^3 and 607950 Pa. The working gas is helium
 Relevant Equations:

Work for adiabatic = area under pV diagram
p1V1^gamma = p2V2^gamma
This is a relatively simple problem, but I'm not getting the right answer. For adiabatic compression, work on gas is positive, since work on gas = ΔEth and the adiabatic process moves from a lower isotherm to a higher one. Integrating for work gives:
pV * (V_{f}^{(1  gamma)}  V_{i}^{(1  gamma)})/(1gamma)
I believe this is correct, but when I plug in the numbers, I'm getting a negative number:
101325 Pa * 0.024 m^{3} * ((0.0082 m^{3})^{1  1.67}  (0.024 m^{3})^{1  1.67})/(1  1.67)
= 3823.6 J
pV * (V_{f}^{(1  gamma)}  V_{i}^{(1  gamma)})/(1gamma)
I believe this is correct, but when I plug in the numbers, I'm getting a negative number:
101325 Pa * 0.024 m^{3} * ((0.0082 m^{3})^{1  1.67}  (0.024 m^{3})^{1  1.67})/(1  1.67)
= 3823.6 J