- #1
Vegie
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Homework Statement
Consider a pump that is required to compress air in a factory. The cylinder in the pump has an inner
diameter of 2.00 cm and length 60.0 cm. Air is drawn into the pump at atmospheric pressure and
18°C and the pump adiabatically compresses the air to a pressure of 17 atmospheres.
Calculate the volume and temperature of the compressed air.
I calculated the volume to be 24.9153 cm3, and the temperature to be 653.8 Kelvin. Volume was found by using the P1V1gamma = P2V2gamma formula, presuming it was a diatomic gas (air), and for temperature just used P1V1/T1 = P2V2/T2 (or could have used the T1V1^gamma-1)
But this question stumps me:
What is the increase in internal energy of the gas during the compression?
Homework Equations
Eint = (5/2) * n * R * T
Eint = (5/2) * N * Kb * T
ΔE = Q + W
W = PΔV
The Attempt at a Solution
My first thought was to use the top equation with the different temperatures and minus them from each other, but realized I didn't have the amount of moles.
My second thought was to use the last equation and sub it into the second to last equation (I know Q=0 since it's adiabatic), but was confused about what pressure to use? Would I use 101300 Pa, or 1722100 Pa (which is 17 atm), or neither?