A gas performs the maximum work, when it expands
A. Non-uniformly
B. Adiabatically
C. Isobarically
D. Isothermally
Answer: Option C
Solution (By Examveda Team)
The Isobaric, isothermal and adiabatic process represented in $$P β V$$ as the following.Since, area under $$P-V$$ plot for isobaric process is more than the isothermal and adiabatic process the work done in isobaric process is highest.
This Question Belongs to Chemical Engineering >> Chemical Engineering Thermodynamics
To determine when a gas performs maximum work during expansion, letβs evaluate each process:
πΉ A. Non-uniformly
Usually implies irreversible or uncontrolled process.
Irreversible processes do not give maximum work.
β Incorrect
πΉ B. Adiabatically
No heat exchange.
Work is done at the expense of internal energy.
Compared to isothermal expansion, less work is done for the same volume change.
β Incorrect
πΉ C. Isobarically (constant pressure)
Work =
π
=
π
(
π
2
β
π
1
)
W=P(V
2
β
βV
1
β
)
Less work than isothermal expansion for an ideal gas under similar conditions.
β Incorrect
πΉ D. Isothermally (constant temperature)
For ideal gases, reversible isothermal expansion gives:
π
=
π
π
π
ln
β‘
(
π
2
π
1
)
W=nRTln(
V
1
β
V
2
β
β
)
This is the maximum possible work a gas can do between two volumes, since heat continuously enters to keep temperature constant and support expansion.
β Correct answer: D. Isothermally