Question

A gas is allowed to expand in a cylinder against a constant external pressure of 2.5 bar, from an initial volume of 2.5 L to a final volume of 4.5 L. The work done in Joule will be _____________ *
a) -500 J
b) -506 J
c) +506 J
d) 1136 J​

Answer 1

Answer:

The answer would be option b - 506 J

Explanation:

The change in the internal energy is given by the following expression.

                             ΔU=q+W

Since container is well insulated,

                                q=0.

Hence ΔU=W=−PΔV

           ΔU=W=−2.5atm×(4.50L−2.50L)

           ΔU=W=−5.0Latm

Convert the unit to J

           ΔU= W = −5.0 L atm ×  $\frac{101.33 J }{1 L atm }$ = −506J

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