Using Energy Concepts and the Ideal Gas Model

Two-tenths kmol of nitrogen (N2) in a piston-cylinder assembly undergoes two processes in series as follows:

Process 1−2: Constant pressure at 5 bar from V1 = 1.33 m3 to V2 = 1 m3.

Process 2−3: Constant volume to p3 = 4 bar.

Assuming ideal gas behavior and neglecting kinetic and potential energy effects, determine the work and heat transfer for each process, in kJ.

Step 1 of 3</p>

We are required to calculate the work and heat transfer.

Step 2 of 3</p>

The p-V diagram for the given process can be shown as below.

Process 1-2,

This process occurs at constant pressure.

The work done at constant pressure and changing volume process is,

Given data:

bar

N/m2

m3

m3

Therefore, J

kJ

Given,

kmol

From,

K

K

From the relation,

K

K

For the process 2-3,

K

K

Therefore, from table A-23 for nitrogen,

At temperature 300 K, kJ/kmol

At temperature 400 K, kJ/kmol

The heat transferred in process 1-2 is,

kJ

kJ

Therefore, the heat transferred in the process 1-2 is -582 kJ.