12.5 In changing the state of a gas adiabatically from an equilibrium state A to another equilibrium state B, an amount of work equal to 22.3 J is done on the system. If the gas is taken from state A to B via a process in which the net heat absorbed by the system is 9.35 cal, how much is the net work done by the system in the latter case? (Take 1 cal = 4.19 J)
The first process is an adiabatic process. So, ΔQ = 0.
ΔW = –22.3 J (Since the work is done on the system)
According to the first law of thermodynamics,
ΔQ = ΔU + ΔW
ΔU = ΔQ – ΔW = – (– 22.3 J)
ΔU = + 22.3 J
In the second process, the net heat absorbed by the system is:
ΔQ = 9.35 cal = 9.35 × 4.19 = 39.1765 J
Again according to the first law of thermodynamics, ΔQ = ΔU + ΔQ
ΔW = ΔQ – ΔU
= 39.1765 – 22.3
= 16.8765 J
Therefore, 16.88 J of work is done by the system.
© 2024 GoodEd Technologies Pvt. Ltd.
