Question

A piston-cylinder assembly containing 3 kg of an ideal gas
undergoes a constant pressure process from an initial volume of 48
m^{3} to a final volume of 30 m^{3} . During the
process, the piston supplies 1.2 MJ of work to the gas. The gas has
a constant specific heat at constant volume of 1.80 kJ/(kg∙K) and a
specific gas constant of 1.48 kJ/(kg∙K). Neglect potential and
kinetic energy changes.

a. Determine the initial specific volume of the gas in
m^{3} /kg.

b. Determine the final specific volume of the gas in
m^{3} /kg.

c. Determine the pressure of the gas in kPa.

d. Determine the initial temperature of the gas in ⁰C

e. Determine the final temperature of the gas in ⁰C f. Determine the specific heat transfer to the gas in MJ/kg.

Answer #1

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.

5 kg of air in a piston cylinder assembly undergoes a Carnot
power cycle. Heat is received at temperature?1=727°C and rejected
at ?3=27°C.During the heat input process, the pressure changes from
?1=1200kPa to ?2=900kPa, respectively. Assume the air behaves as an
ideal gas with constant specific heats.
Determine:
a.pressures [kPa] at beginning and end of the isothermal heat
rejection process (?3,?4)
b.heat transfer from high temperature source [kJ]
c.thermal efficiency
d.net work output for cycle [kJ]

Oxygen gas is contained in a piston cylinder assembly at an
initial pressure of 1000 kPa and expands from 0.2 m3 to 1.0 m3 by a
process where PV = constant. The gas has an internal energy change
of -200 kJ. Calculate the work (kJ) and the heat transfer (kJ) done
during the process.

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]

One kg of water in a piston-cylinder assembly
undergoes two processes in series from an initial state where p1 =
0.8 MPa, T1 = 500°C:
Process 1-2: Constant-pressure compression until the
volume is half of
the initial volume.
Process 2-3: Constant-volume cooling until the
pressure drops to 400 kPa.
Sketch the two processes in series on a p-v and T-v
diagram. Determine the work and heat transfer for both
processes.

A gas undergoes a process in a piston–cylinder assembly during
which the pressure-specific volume relation is
pv1.2 = constant. The mass of the gas
is 0.4 lb and the following data are known: p1
= 160 lbf/in.2, V1 = 1
ft3, and p2 = 300
lbf/in.2 During the process, heat transfer from
the gas is 2.1 Btu. Kinetic and potential energy effects are
negligible. Determine the change in specific internal energy of the
gas, in Btu/lb.
Δu=

1) An ideal gas is contained in a
piston-cylinder device and undergoes a power cycle as follows:
1-2 isentropic compression from an initial
temperatureT1= 20 degree celsius with a compression ratio
r = 5
2-3 constant pressure heat addition 3-1 constant volume heat
rejection
The gas has constant specific heats with cv = 0.7
kJ/kg·K and R= 0.3 kJ/kg·K.
(a) Sketch the
P-v and T-s diagrams for the cycle.
(b) Determine the heat
and work interactions for each pro-cess, in...

A 0.2 m3 piston-cylinder initially contains 400 K air. A heavy
frictionless piston maintains a pressure of 500 kPa abs. Then, a
weakness in the cylinder wall blows out and creates a hole. Air
escapes through the hole until the piston drops far enough to cover
the hole. At that point, the volume is half the initial volume.
During this process, 75 kJ of heat is transferred to the 100 kPa,
300 K surroundings. Using Cp = 1.005 kJ/kg-K and...

A cylinder with a moveable piston holds 1.20 mol of argon at a
constant temperature of 295 K. As the gas is compressed
isothermally, its pressure increases from 101 kPa to 145 kPa.
(a) Find the final volume of the gas. (answer in:
m3)
(b) Find the work done by the gas. (answer in: kJ)
(c) Find the heat added to the gas. (.. kJ)

A piston cylinder device contains a mixture of 0.2 kg of H2 and
1.6 kg of N2 at 100 kPa and 300K. Heat is now transferred to the
mixture at constant pressure unitl the volume is doubled. Assuming
constant specific heats at the average temperature (the constant
pressure specific heats of H2 and N2 are 14.501 kJ/kg°K and 1.049
kJ/kg°K, respectively), determine: a) the heat transfer. b) the
entropy change of the mixture.

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