Calculate the work engergy gained or lost by the system when a gas expands from 35 to 55 l against a constant external presure of 3atm.

 The work energy lost by the system is -6078 Joules

Explanation:

According to first law of thermodynamics:

=Change in internal energy

q = heat absorbed or released

w = work done or by the system

w = work done by the system=  {Work is done by the system as the final volume is greater than initial volume and is negative}

where P = pressure = 3 atm

= change in volume = (55-35) L = 20 L

w =  

{1Latm=101.3J}

Thus work energy lost by the system is -6078 Joules

a gas, having a molecular weight of 13 kg/kmol and a kinematic viscosity of 0.25 cm2/s, flows through a pipe 0.25 m internal diameter and 5 km long at the rate of 0.4 m3/s and is delivered at atmospheric pressure.