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How to solve this problem- - Chemical Thermodynamics - NEET

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 \DeltaU of the gas in joules will be :

  • Option 1)

    1136.25 J

  • Option 2)

    -500 J

  • Option 3)

    -505 J

  • Option 4)

    +505 J

 
Answers (1)
238 Views

P =2.5\: atm

v_{i}=2.50L

v_{f}=4.50L

\Delta U=?

Word done,

W = -P \Delta v

=-2.5\left ( 4.50-2.50 \right )

=-5L-atm

=-5\times 101.3 J

=-506.5J

Now, for adiabate process, f=0

\therefore \Delta U=f+w

=-506.5J

=-505J

 


Option 1)

1136.25 J

This option is incorrect.

Option 2)

-500 J

This option is incorrect.

Option 3)

-505 J

This option is correct.

Option 4)

+505 J

This option is incorrect.

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