Question

Carbon dioxide (CO_{2}) is compressed in a
piston–cylinder assembly from *p*_{1} = 0.7 bar,
*T*_{1} = 280 K to *p*_{2} = 14 bar.
The initial volume is 0.2 m^{3}. The process is described
by *pV*^{1.25} = *constant*.

Assuming ideal gas behavior and neglecting kinetic and potential
energy effects, determine the work and heat transfer for the
process, each in kJ, using constant specific heats evaluated at 300
K, and data from Table A-23.

Answer #1

Steam undergoes an isentropic compression in an insulated
piston–cylinder assembly from an initial state where T1 = 120°C, p1
= 1 bar to a final state where the pressure p2 = 20 bar. Determine
the final temperature, in °C, and the work, in kJ per kg of steam.
The final temperature equals 513.87°C.

H3.3 A frictionless piston-cylinder device contains 2 kg of H2O
initially at T1 = 300◦C and p1 = 5 bar. The device is cooled at
constant pressure until the volume is ∀2 = 0.5 m3 . Assume a
quasiequillibrium process which occurs slowly with no acceleration
as the piston moves. Kinetic and potential energy effects are
negligible. Determine: a. work [kJ] during process (indicate
magnitude and direction) b. heat transfer [kJ] during process
(indicate magnitude and direction)

Problem 6.100 SI
Carbon dioxide (CO2) at 1 bar, 300 K enters a
compressor operating at steady state and is compressed
adiabatically to an exit state of 10 bar, 590 K. The CO2
is modeled as an ideal gas, and kinetic and potential energy
effects are negligible.
For the compressor, determine:
(a) the work input, in kJ per kg of CO2 flowing,
(b) the rate of entropy production, in kJ/K per kg of
CO2 flowing, and
(c) the percent isentropic...

Carbon dioxide (CO2) gas is compressed at steady state from 0.8
bar and 17 °C to 3.5 bar with a compressor drawing 10 kW of power.
The CO2 flows through the compressor at a rate of 0.1 m3/s through
an inlet orifice that is 200 cm2. The gas leaves the compressor at
a velocity of 12 m/s. Heat loss from the compressor to the
surroundings is roughly 2% of the power fed to the compressor. In
addition to the Give,...

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.

In a cylinder/piston arrangement, air is compressed in a
reversible polytropic process to a final state of 800 kPa, 500 K.
Initially air is at 110 kPa and 25oC. During the
compression process heat transfer takes place with the ambient
maintained at 25oC. Assume air as an ideal gas (R =0.287
kJ/kg) and has constant specific heats of Cp = 1.004
kJ/kgK and Cv = 0.717 kJ/kgK. If the mass of air in the
cylinder is 0.1286 kg, determine
a)...

A rigid, well-insulated tank, with a volume of 0.057 m3 ,
contains air at p1 = 1.4 bar, T1 = 280 K. The air is stirred by a
paddle wheel, resulting in an energy transfer to the gas of
magnitude 6.78 kJ. Assuming ideal gas behavior for the air,
determine the final temperature, in K, and the final pressure, in
bar. Neglect kinetic and potential energy effects

A cylinder contains 0.200 mol of carbon dioxide (CO2) gas at a
temperature of 30.0 ∘C. The cylinder is provided with a
frictionless piston, which maintains a constant pressure of 1.00
atm on the gas. The cylinder is placed on a hot plate and a 920 J
of heat flows into the gas, thereby raising its temperature to 124
∘C. Assume that the CO2 may be treated as an ideal gas.
What is the change in internal energy of the...

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.

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=

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