The First Law of Thermodynamics (Concept of Work, Heat Internal Energy and Enthalpy, Heat Capacity,...) NEET Questions

Physical Chemistry - Chemical Thermodynamics

The First Law of Thermodynamics (Concept of Work, Heat Internal Energy and Enthalpy, Heat Capacity,...) MCQ Questions


13.
The work done in expansion of a gas against constant external pressure is given by:
A.
w = +pexΔV
B.
w = ΔV/pex
C.
w = −pexΔV
D.
w = pex/ΔV
😑 View Answer Rough Work Error
ANSWER :
C. w = −pexΔV
14.
For isothermal reversible expansion of an ideal gas, work done is:
A.
w = −nRT(Vf − Vi)
B.
w = +pexΔV
C.
w = +nRT ln(Vf/Vi)
D.
w = −nRT ln(Vf/Vi)
😑 View Answer Rough Work Error
ANSWER :
D. w = −nRT ln(Vf/Vi)
15.
Free expansion of an ideal gas into vacuum involves:
A.
No work done at all
B.
Maximum work done by the gas
C.
Work done equals nRT ln(Vf/Vi)
D.
Work done against atmospheric pressure
😑 View Answer Rough Work Error
ANSWER :
A. No work done at all
16.
1 mole of an ideal gas expands isothermally and reversibly from 1 L to 10 L at 300 K. Work done is approximately (R = 8.314 J K⁻¹ mol⁻¹):
A.
−5740 J
B.
+2740 J
C.
+5740 J
D.
−2740 J
😑 View Answer Rough Work Error
ANSWER :
A. −5740 J
17.
Maximum work is obtained when expansion of a gas is carried out:
A.
In a single step
B.
Against vacuum
C.
Reversibly
D.
Against constant external pressure
😑 View Answer Rough Work Error
ANSWER :
C. Reversibly
18.
For a reversible isothermal expansion of an ideal gas at temperature T from volume V₁ to V₂, q is:
A.
−nRT ln(V₂/V₁)
B.
+nRT ln(V₂/V₁)
C.
+nRT(V₂−V₁)
D.
Zero
😑 View Answer Rough Work Error
ANSWER :
B. +nRT ln(V₂/V₁)