STANDARDChemistry-Thermodynamics

STANDARD Chemistry First law of thermodynamics MCQ Question

Type: MCQ-numerical-Medium-Class 11

A gas is allowed to expand in a well insulated container against a constant external pressure of 2.5 atm from an initial volume of 2.50 L to a final volume of 4.50 L. The change in internal energy ΔU of the gas in joules will be

A

−500 J

B

−500 J

C

+500 J

D

1136.25 J

Correct Answer

Option B

Detailed Explanation

The work done is w = −PₑₓₜΔV = −2.5(4.50 − 2.50) = −5 L atm = −5 × 101.325 J = −506.625 J. Since the container is insulated, q = 0, hence, ΔU = w = −506.625 J.

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