1.
Substance
Temp
(C)
Water
140
Ammonia
20
100 kPa
Water
100
30
Ammonia
50
Water
20
Water
Pressure
(MPa)
Specific
Volume
Internal
Energy
Specific
Enthalpy
Specific
Entropy
Quality
Phase
0.5
0.1185
1 bar
3 bar
0.5
2. Dr. Pabilona developed a new absolute temperature scale in which the boiling and freezing points of water at
atmospheric pressure are 500°X and 100°X , respectively. Develop a relation to convert this scale to degrees celsius.
Assume that 50°C is read on that temperature scale, how much is the value in terms of °X?
3. A 500-liter tank contains a saturated mixture of steam and water at 300°C. Determine (a) the mass of each phase if the
volumes are equal, (b) the volume occupied by each phase if their masses are equal.
4. Water in a 150-L closed, rigid tank is at 100°C and 90% quality. The tank is then cooled to −10°C. Calculate the heat
transfer for the process.
5. A closed steel bottle contains carbon dioxide at −20°C, x = 20% and the volume is 0.05 m^3. It has a safety valve that
opens at a pressure of 6 MPa. By accident, the bottle is heated until the safety valve opens. Find the temperature and heat
transfer when the valve first opens.
6. A Carnot engine produces 25 kW while operating between temperature limits of 1000K and 300 K. Determine (a) heat
supplied per second, (b) heat rejected per second.
7. A Carnot refrigerator operates between temperature limits of 5°C and 30°C. The power consumed is 4 kW and the heat
absorbed is 30 kJ/kg. Determine (a) the COP, (b) the refrigerant flow rate.
8. In a process outlined by a p-V diagram, state 1 is characterized by constant volume with state 2. State 1 has a pressure
of 1248 kPa and a temperature of 600K, while state 2 has a pressure of 3178 kPa and a temperature of ..?
9. Saturated liquid water at 100°C is contained in a piston-cylinder assembly. The water undergoes a process to the
corresponding saturated vapor state, during which the piston moves freely in the cylinder. There is no heat transfer with
the surroundings. If the change of state is brought about by the action of a paddle wheel, determine the network per unit
mass, in kJ/kg, and the amount of entropy produced per unit mass, in kJ/kg-K.
10. Steam enters a turbine with a pressure of 3 MPa, a temperature of 400°C, and a velocity of 160m/s. Saturated vapor at
100°C exits with a velocity of 100m/s. At steady-state, the turbine develops work equal to 540 kJ/kg. Heat transfer
between the turbine and its surroundings occurs at an average outer surface temperature of 350K. Determine the rate at
which entropy is produced within the turbine per kg of steam flowing, in kJ/kg-K. Neglect the change in potential energy
between inlet and exit.