Question

A gas can expand from 100 mL to 250 mL under a constant pressure of 2 atm. The work done by the gas is:

• A. 30.48 J
• B. 25 J
• C. 5 kJ
• D. 16 J

Answer 1

The correct option is A 30.48 J

Solution:- (A) $30.4J$

As we know that, work done is given as-

$W=-P_{ext.}\Delta V$

Given:-

$P_{ext.}=2atm$

$V_i=100mL=0.1L$

$V_f=250mL=0.25L$

$\Delta V=V_f-V_i=0.25-0.1=0.15L$

$\therefore W=-2\times 0.15=-0.3L-atm=-30.4J$

Here $-ve$ sign indicates that the work is done by the gas.

Hence the work done by the gas is $30.4J$.