Question

An ideal gas with ?=1.4 occupies 5.5L at 300 K and 150kPa pressure and is compressed adiabatically until its volume is 2.0 L. It's then cooled at constant pressure until it reaches 300 K, then allowed to expand isothermally back to state A.

A)Find the net work done on the gas
B) Find the minimum volume reached.

Answer 1

Answer 2

A. NET WORK DONE W = WORK DONE DUE TO ISOTHERMAL + WORK DONE DUE TO ADIABATIC CHANGE

W = 2.3RT Log ( V₂ / V₁ ) + R( T₁ - T₂ ) / ( $\gamma$ - 1 )

= 2.3 x 8.3 x Log( 2.0 / 5.5 ) + (8.3 x 300 ) / ( 1.4 - 1) = 6226.06J

B.SINCE THE TEMPERATURE COMES BACK TO INITIAL VALUE AND THE PRESSURE IS CONSTANT HENCE THE MINIMUM VOLUME WILL REMAIN CONSTANT THAT IS 2.0L.