Question

1 kg of water in a piston cylinder arrangement is initially in a saturated liquid state at 1 bar. It undergoes expansion at constant pressure due to external heat supply to it, to a final state of saturated vapor.

(i) What is the initial temperature of water in C? (a) 93.50 (b) 96.71 (c) 99.63 (d) 111.4 (e) 12.2

(ii) What is the change in enthalpy of water (kJ/kg-K)? (a) 417.46 (b) 2258.0 (c) 2675.5 (d) 2506.1

(iii) What is the change in entropy of water (kJ/kg-K)? (a) 1.3026 (b) 7.3594 (c) 6.0568 (d) 8.6620

Answer #1

Water, initially (state 1) a saturated liquid at
1100C, is contained in a piston-cylinder assembly. The
water undergoes a process to the corresponding saturated vapor
(state 2), during which the piston moves freely in the cylinder. If
the change of state is brought about by heating the water as it
undergoes an internally reversible process at constant pressure and
temperature, determine (a) heat transfer using first law of
thermodynamics in kJ/kg and (b) heat transfer using second law of
thermodynamics...

500 g of saturated liquid water is contained in a
piston-cylinder arrangement. The inside diameter of the cylinder is
100 mm. The water is heated at a constant pressure of 150 kPa until
it becomes saturated vapor. Determine (a) the distance through
which the piston is raised, and (b) the amount of energy
transferred to the water.

A vertical, insulated piston cylinder is filled with saturated
liquid H2O at 50 kPa. A stirrer moves rapidly inside the cylinder
until 22% of the H2O (by mass) evaporates. Determine the net work
done (in kJ/kg), the change in entropy during this process (in
kJ/kg-K) and the entropy generated during this process (in
kJ/kg-K).

Water undergoes a constant‐volume process within a
piston–cylinder assembly from saturated liquid at 4 bar to a final
pressure of 50 bar. Kinetic and potential energy effects are
negligible. Determine the work and the heat transfer, each in kJ
per kg of water. [7 points]

Initially (state 1) a well-insulated rigid tank contains 20 kg
of a saturated liquid-vapor mixture of water at 100 kPa and half 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 (state 2). Determine (a) the
initial specific volume in m3/kg, (b) the final specific
entropy in kJ/kg.K and (c) change of entropy in kJ/K.

Initially (state 1) a well-insulated rigid tank contains 20 kg
of a saturated liquid-vapor mixture of water at 100 kPa and half 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 (state 2). Determine (a) the
initial specific volume in m3/kg, (b) the final specific
entropy in kJ/kg.K and (c) change of entropy in kJ/K.

A mass of one kg of water within a piston–cylinder assembly
undergoes a constant-pressure process from saturated vapor at 500
kPa to a temperature of 260°C. Kinetic and potential energy effects
are negligible. For the water:
a) Evaluate the work, in kJ,
b) If the work is 30 kJ, evaluate the heat transfer, in kJ,
c) If the heat transfer is negligible, evaluate the entropy
production in kJ/K
d) Determine if the process is reversible, irreversible, or
impossible.

Entropy From Steam Tables
A piston-cylinder assembly contain 2 kg of water. The water is
initially at the pressure of 0.5 MPa and the temperature of 300°C.
The water is cooled down at constant pressure process until it is a
saturated vapor. Determine the change in the entropy of the
system.

A piston-cylinder device initially contains 75 g of saturated
water vapor at 340 kPa . A resistance heater is operated within the
cylinder with a current of 0.6 A from a 300 V source until the
volume doubles. At the same time a heat loss of 7 kJ occurs.
Part A)Determine the final temperature (T2).
Part B)Determine the duration of the process.
Part C)
What-if scenario: What is the final
temperature if the piston-cylinder device initially contains
saturated liquid water?

A cylinder-piston device contains a mass of 2.4 kg of
liquid-vapor mixture water with 70% titer at 50 bar. The system
goes through a process of cooling to constant pressure until the
obtaining compressed liquid with 14 ºC of subcooling. Evaluate:
(i) The initial and final temperatures of the process.
(ii) The specific enthalpy at the beginning of the process.
(iii) The change in total volume during the process.
(iv) The amount of heat removed from the system during the...

ADVERTISEMENT

Get Answers For Free

Most questions answered within 1 hours.

ADVERTISEMENT

asked 9 minutes ago

asked 12 minutes ago

asked 16 minutes ago

asked 27 minutes ago

asked 28 minutes ago

asked 40 minutes ago

asked 57 minutes ago

asked 58 minutes ago

asked 1 hour ago

asked 1 hour ago

asked 1 hour ago

asked 1 hour ago