1. ES340
Sample Exam III Problems
Fall 2013
Neglect kinetic and potential energy in all problems. No interpolation is necessary, take the
closest value.
1. (35) Air contained in a rigid, insulated tank fitted with a paddle wheel, initially at
300K, 2 bar, and a volume of 2 m3, is stirred until its temperature is 500 K. Assuming
the ideal gas model for the air, and ignoring kinetic and potential energy change,
determine
A. The final pressure, bar
B. The work, kJ
C. The amount of entropy production, in kJ/K
2. (35) Air modeled as an ideal gas enters a turbine operating at steady state at 1040 K,
278 kPa and exits at 120.126 kPa. The mass flow rate is 5.501 kg/s, and the power
developed is 1120 kW. Stray heat transfer and kinetic and potential are neglected,
determine
A. The temperature of at turbine exit, in K
B. The isentropic turbines efficiency
C. Represent this process in T-s diagram.
3. (30) A vessel whose volume is 1m3 contains 4kmol of methane at 100oC, determine
the pressure using following equations.
A. Ideal gas equation of state
B. Van der waal’s equation of state
C. Redlich-kwong equation of state