A frictionless piston cylinder device contains 5 kg of steam at 400 kPa and 200°C. The heat is now transferred to the steam until the temperature reaches 250°C. If the piston is not attached to a shaft, its mass is constant, and by taking the values of specific volume v1 as 0.53434 m3/kg and v2 as 0.59520 m3/kg, the work done by the steam during this process is
1. 121.7 kJ
2. 137.5 kJ
3. 153.3 kJ
4. 189.1 kJ
