Question

One mole of an ideal gas is contained within a cylinder by a frictionless piston and is initially at temperature T. The pressure of the gas is kept constant while it is heated and its volume doubles. If R is molar gas constant, the work done by the gas in increasing its volume is ..............RT.

Answer 1

Ideal gas equation $PV=nRT$

Initial position: $PV=RT$ as mole of gas is one,

Final position: $P2V=2RT$ as volume doubles & P is constant.

So the work done by the gas in increasing its volume is:

$W=P△V=P_2{V}_2-P_1{V}_1=2RT-RT=1\times RT$.

The correct answer is 1.