Apiston-cylinder device contains 1.329 kg of nitrogen gas at 120 kpa and 27 degree c. the gas is now compressed slowly in a polytropic process during which pv^1.49 = constant. the process ends when the volume is reduced by one-half. determine the entropy change of nitrogen during this process.

-0.4199 J/k

Explanation:

Given data

mass of nitrogen(m)=1.329 Kg

Initial pressure=120KPa

Initial temperature 300k

Final volume is half of initial

R=particular gas constant

Therefore initial volume of gas is given by

PV=mRT

V=0.986\times 10^{-3}

Using =constant

=

=337.066KPa

=

and entropy is given by

=+

Where, ==0.6059

==0.9027

Substituting values we get

=+

=-0.4199 J/k