Chapter 6, Problem 6.32CU

Steam at a pressure of 21 bar and a dryness fraction of 0.9 occupies a volume of 0.427 m' in a cylinder behind a piston is allowed to expand reversibly to a pressure of 7 bar according to the relationship, PV1.25 = Constant. Sketch the process on the p-v diagram and calculate the work and heat transfers in kJ. %3D

A vessel of volume 0.04 m3 contains a mixture of saturated water and steam at a temperatureof 250°C. The mass of the liquid present is 9 kg. Find the pressure, mass, specific volume,enthalpy, entropy and internal energy.

4. Choose the correct statement/s with respect to entropy change during a process a. Entropy increases with increase in pressure at constant temperatureb. Entropy increases with increase in temperature at constant pressurec. Entropy can be kept constant by systematically increase both pressure and temperatured. Entropy can not be changed

for steam, the specific ideal gas constant = 461.5 J/kg K A closed system is comprised of pure water substance initially at a temperature of 500 oC and a pressure of 20 MPa (state 1). The system undergoes an isochoric process whereby its pressure drops to 0.1 Mpa (state 2). Evaluate the specific entropy, specific volume and temperature of the system at state 2.

A 300-lb iron casting, initially at 1500°F, is quenched in a tank filled with 2121 lb of oil, initially at 80°F. The iron casting and oil can be modeled as incompressible with specific heats 0.10 Btu/lb · °R, and 0.45 Btu/lb · °R, respectively. (a) For the iron casting and oil as the system,determine the final equilibrium temperature, in °F. Ignore heat transfer between the system and its surroundings. Tf = i °F (b) For the iron casting and oil as the system,determine the amount of entropy produced within the tank, in Btu/°R. Ignore heat transfer between the system and its surroundings. O = i Btu/°R

7.450 kg of steam at a pressure of 20 bar and temperature of 300 deg C expands isentropically to a pressure of 0.5 bar. Determine the work done on steam in kJ during expansion. Use steam tables of keenan et al

Suppose that 0.27 kg of water is contained in a vertical cylinder/piston arrangement as a 2 phase mixture at 50°C. Initially the volume beneath the 125 kg piston (area of 8.77 cm2) is 0.03 m^3. With the atmospheric pressure of 101.325 kPa (g = 9.81 m/s^2), the piston is resting on the stops. Energy is transferred to this arrangement until the piston rises from the stops. a) What is the temperature of the water when the piston first rises from the set of stops? b) What is the temperature at which the system reaches the saturated vapor state? c) Show the process on a T-v diagram and label the known states on the diagram.

An ideal gas is confined to one side of a rigid, insulated container divided by a partition. The other side is initially 500 K, and V1 =0.2 m³. When the partition is removed, the gas expands to fill the entire container, which has a total volume of 0.5 m³. Assuming evacuated. The following data are known for the initial state of gas: P1 = 5 bar, T1 %3D that there is no change in the internal energy of the gas, determine the (a) pressure, in bar and the (b) product of mass, specific gas constant and T in the final state (in kPa-m³).

Explain the following terms in relation to a system - Boundry, surroundings, equilibrium, phase, pure substance, entropy.