A 20-ft^3 rigid tank initially contains saturated refrigerant- 134a vapor at 160 psia. As a result of heat transfer from the refrigerant, the pressure drops to 50 psia. Show the process on a P-v diagram with respect to saturation lines and determine (a) the final temperature, (b) the amount of refrigerant that has condensed, and (c) the heat transfer.

A $0.06-m^{3}$ rigid tank initially contains refrigerant-134a at 0.8 MPa and 100 percent quality. The tank is connected by a valve to a supply line that carries refrigerant-134a at 1.2 Mpa and $36^{\circ} \mathrm{C}$. Now the valve is opened, and the refrigerant is allowed to enter the tank. The valve is closed when it is observed that the tank contains saturated liquid at 1.2 MPa. Determine (a) the mass of the refrigerant that has entered the tank and (b) the amount of heat transfer.

A 5-ft^3 rigid tank contains a saturated mixture of refrigerant-134a at 50 psia. If the saturated liquid occupies 20 percent of the volume, determine the quality and the total mass of the refrigerant in the tank.

A 0.5-m^3 rigid tank contains refrigerant-134a initially at 160 kPa and 40 percent quality. Heat is now transferred to the refrigerant until the pressure reaches 700 kPa. Determine (a) the mass of the refrigerant in the tank and (b) the amount of heat transferred. Also, show the process on a P-v diagram with respect to saturation lines.

A well-insulated rigid tank contains 3 kg of saturated liquid-vapor mixture of water at 200 kPa. Initially, three-quarters of the mass is in the liquid phase. An electric resistance heater placed in the tank is now turned on and kept on until all the liquid in the tank is vaporized. Determine the entropy change of the steam during this process. Answer: 11.1 kJ/K

A 0.5-m^3 rigid tank contains refrigerant-134a initially at 200 kPa and 40 percent quality. Heat is transferred now to the refrigerant from a source at 35$^\circ{}$C until the pressure rises to 400 kPa. Determine (a) the entropy change of the refrigerant, (b) the entropy change of the heat source, and (c) the total entropy change for this process.

Is $\ce{N2O4}$ molecular or empirical formula?

A $5- \mathrm{ft}^{3}$ rigid tank initially contains refrigerant-134a at 60 psia and 100 percent quality. The tank is connected by a valve to a supply line that carries refrigerant-134a at 140 psia and $80^{\circ} \mathrm{F}.$ The valve is now opened, allowing the refrigerant to enter the tank, and is closed when it is observed that the tank contains only saturated liquid at 100 psia. Determine (a) the mass of the refrigerant that entered the tank. (b) the amount of heat transfer with the surroundings at $70^{\circ} \mathrm{F},$ and (c) the entropy generated during this process.

A rigid 1-ft^3 vessel contains R-134a originally at -20$^\circ{}$F and 27.7 percent quality. The refrigerant is then heated until its temperature is 100$^\circ{}$F. Calculate the heat transfer required to do this. Answer: 84.7 Btu

If sufficient data are provided, complete the blank cells in the following table of properties of water. In the last column describe the condition of water as compressed liquid, saturated mixture, superheated vapor, or insufficient information; and, if applicable, give the quality.

$$\begin{matrix} \text{P, kPa} & T, ^\circ C & v, m^3/kg & \text{u, kJ/kg} & \text{Phase description}\\ \quad & \text{250} & \quad & \text{2728.9}\\ \text{300} & \quad & \quad & \text{1560.0}\\ \text{101.42} & \text{100} & \quad & \quad\\ \text{3000} & \text{180} & \quad & \quad\\ \end{matrix}$$

A rigid copper tank, initially containing $1 \: m^3$of air at 295 K, 5 bar, is connected by a valve to a large supply line carrying air at 295 K, 15 bar. The valve is opened only as long as required to fill the tank with air to a pressure of 15 bar. Finally, the air in the tank is at 310 K. The copper tank, which has a mass of 20 kg, is at the same temperature as the air in the tank, initially and finally. The specific heat of the copper is $c = 0.385 \: kJ/kg \cdot K$. Assuming ideal gas behavior for the air, determine (a) the initial and final mass of air within the tank, each in kg, and (b) the heat transfer to the surroundings from the tank and its contents, in kJ, ignoring kinetic and potential energy effects.

A frictionless piston-cylinder device contains 5 kg of nitrogen at 100 kPa and 250 K. Nitrogen is now compressed slowly according to the relation $PV^{1.4}$ = constant until it reaches a final temperature of 450 K. Calculate the work input during this process.

A frictionless piston–cylinder device contains 5 kg of nitrogen at 100 kPa and 250 K. Nitrogen is now compressed slowly according to the relation PV^1.4=constant until it reaches a final temperature of 360 K. Calculate the work input during this process.

Propane is compressed isothermally by a piston-cylinder device from $100^{\circ} \mathrm{C}$ and 1 MPa to 4 MPa. Using the generalized charts, determine the work done and the heat transfer per unit mass of propane.