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The temperature of an ideal gas in a sealed 0.50 m3 container is reduced from 40

ID: 2151178 • Letter: T

Question

The temperature of an ideal gas in a sealed 0.50 m3 container is reduced from 400 K to 270 K. The final pressure of the gas is 80 kPA. The molar heat capacity at constant volume of the gas is 28.0 . The work done by the gas, in kJ, is closest to:
The temperature of an ideal gas in a sealed 0.50 m3 container is reduced from 400 K to 270 K. The final pressure of the gas is 80 kPA. The molar heat capacity at constant volume of the gas is 28.0 . The work done by the gas, in kJ, is closest to:
zero
-65
-84
65
84


I'm getting -65kJ but i got it wrong than it said work don by the gas so i thought it was positive
but i still got it wrong. now i am not sure what the answer is.

Explanation / Answer

Isn't the work done zero in a constant volume process? Since there is no change in volume, work done defined by

W= P * dV = 0

This implies that the change in internal energy of the gas is equal to the heat liberated by the gas. (First law of thermodynamics)