5kg of nitrogen gas contained in a piston-cylinder arrangement expands in a process, such that pv1.4=p1v11.4, where p1 and v1 are the initial pressure and specific volume, from a pressure of 20 bar to a pressure of 1 bar and a temperature of 300K.
a. What is the initial temperature of the nitrogen?
b. How much work is done by the nitrogen as it expands?
I'm not sure which relationships to use or how to even get started for both parts
The Attempt at a Solution
For part b, we will use the conservation of energy:
U2 + Ke2 + Pe2 = U1 + Ke1 + Pe1 + Q - W
So change in Pe and change in Ke is zero?
Thus, W = U2 - U1 - Q