Refrigerant 134a initially at $-36^{\circ} \mathrm{C}$ fills a rigid vessel. The refrigerant is heated until the temperature becomes $25^\circ C$ and the pressure is 1 bar. There is no work during the process. For the refrigerant, determine the heat transfer per unit mass and the change in specific exergy, each in kJ/kg. Comment. Let $T_{0}=20^{\circ} \mathrm{C}, p_{0}=0.1 \mathrm{MPa}.$

A closed, rigid tank contains Refrigerant 134a, initially at $100^{\circ} \mathrm{C}$. The refrigerant is cooled until it becomes saturated vapor at $20^{\circ} \mathrm{C}$. For the refrigerant, determine the initial and final pressures, each in bar, and the heat transfer, in kJ/kg. Kinetic and potential energy effects can be ignored.

One kilogram of Refrigerant 134a contained within a piston-cylinder assembly undergoes a process from a state where the pressure is 7 bar and the quality is $50 \%$ to a state where the temperature is $16^{\circ} \mathrm{C}$ and the refrigerant is saturated liquid. Find the change in specific entropy of the refrigerant, in $\mathrm{kJ} / \mathrm{kg} \cdot \mathrm{K}$. Can this process be accomplished adiabatically?

Find the greatest number In the data set. {23, 35, 31, 28, 26, 34}

Water at $24^{\circ} \mathrm{C}, 1\ \text{bar}$ is drawn from a reservoir $1.25 \mathrm{~km}$ above a valley and allowed to flow through a hydraulic turbine-generator into a lake on the valley floor. For operation at steady state, determine the maximum theoretical rate at which electricity is generated, in MW, for a mass flow rate of $110 \mathrm{~kg} / \mathrm{s}$. Let $T_0=24^{\circ} \mathrm{C}, p_0=1\ \text{bar}$ and ignore the effects of motion.

The following term reduces to zero within the steady-state form of the closed system exergy rate balance. a. The time rate of the change of exergy within the closed system b. The time rate of exergy transfer by work c. The time rate of exergy transfer by heat d. The time rate of exergy destruction

When the exergy of a system increases, its state moves ________ the dead state.

One pound of air is contained in a closed, rigid, insulated tank. Initially the temperature is $500^{\circ} \mathrm{R}$ and the pressure is $1 \mathrm{~atm}$. The air is stirred by a paddle wheel until its temperature is $700^{\circ} \mathrm{R}$. Using the ideal gas model, determine for the air the change in exergy, the transfer of exergy accompanying work, and the exergy destruction, all in Btu. Ignore the effects of motion and gravity and let $T_0=500^{\circ} \mathrm{R}$. $p_0=1 \mathrm{~atm}$.

A domestic water heater holds 189 L of water at $60^{\circ} \mathrm{C},$ 1 atm. Determine the exergy of the hot water, in kJ. To what elevation, in m, would a 1000-kg mass have to be raised from zero elevation relative to the reference environment for its exergy to equal that of the hot water? Let $T_{0}=298 \mathrm{K}, p_{0}=1 \mathrm{atm}, g=9.81 \mathrm{m} / \mathrm{s}^{2}$

The Brute Force Bandits is a punk rock band planning their next concert tour. The band has a total of 30 new songs in their repertoire. (a) How many different set lists of 18 songs can the band select to play on the tour? (Hint: Assume that the order in which the songs are listed is irrelevant.) (b) How many different ways are there for the band to record a CD consisting of IS songs chosen from the 30 new songs? (Hint: In recording a CD, the order in which the songs appear on the CD is relevant.)

A mass of 3 kg of saturated liquid-vapor mixture of water is contained in a piston-cylinder device at 160 kPa. Initially, 1 kg of water is in the liquid phase and the rest is in the vapor phase. Heat is now transferred to the water, and the piston, which is resting on a set of stops, starts moving when the pressure inside reaches 500 kPA. Heat transfer continues until the total volume increases by 20 percent. Determine (a) the initial and final temperatures, (b) the mass of liquid water when the piston first starts moving, and (c) the work done during this process. Also, show the process on a $P-v$ diagram.

For the free-falling parachutist with linear drag, assume a first jumper is 70 kg and has a drag coefficient of 12 kg/s. If a second jumper has a drag coefficient of 15 kg/s and a mass of 80 kg, how long will it take him to reach the same velocity the first jumper reached in 9 s?

What is 133% of 90?

Consider 100 kg of steam initially at 20 bar and $240^{\circ} \mathrm{C}$ as the system. Determine the change in exergy, in kJ, for each of the following processes: a. The system is heated at constant pressure until its volume doubles. b. The system expands isothermally until its volume doubles. Let $T_{0}=20^{\circ} \mathrm{C}, p_{0}=1$ bar and ignore the effects of motion and gravity.