A heavily insulated cylinder/piston contains ammonia at 1200 kPa, 60C. The piston is moved, expanding the ammonia

Question:

A heavily insulated cylinder/piston contains ammonia at 1200 kPa, 60C. The piston is moved, expanding the ammonia in a reversible process until the temperature is 20C. During the process 600 kJ of work is given out by the ammonia. What was the initial volume of the cylinder?