Solved: Applying the Entropy Balance: Closed SystemsAir

a.)

Step 1 of 4

We have to find the final temperature of the air contained in a rigid, insulated tank fitted with a paddle wheel, initially at 1 bar, 330 K and a volume of 1.93 m3, receives an energy transfer by work from the paddle wheel in an amount of 400 kJ.

The final temperature can be found using the equation

where,

change in internal energy between final and initial state

energy transfer by work from the paddle

         wheel =kJ = 379.127 Btu

Now,  

where,

mass of the air in lb

 and internal energy of the gas at

  temperature 330 K and final temperature.

Thus,

        )=.127

The mass of the air can be found using ideal gas equation

So,

   kg

         = 4.48 lb