Question

initially air is at 250C and 300 kpa it is compressed isothermally such that its new volume 1/8th of the original volume. Determine the final pressure and work done on air

Answer #1

0.5 kilograms of air are compressed from 100 kPa and 300 K in a
polytropic process, n = 1.3, to a state where V2 = 0.5
V1. The air is further compressed at constant pressure
until the final volume is 0.2 V1 . Draw a sketch of the
processes on a p-V diagram. Determine the work for each
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)...

Show that the work done by an ideal gas during an isothermal
change of state (from initial state 1 to final state 2), in a
closed container is given by; 1W2=m.R.T(ln(v2/v1))
A piston-cylinder device contains 0.2 kg of air, initially at
27oC and 100 kPa. The air is then slowly compressed in an
isothermal process to a final pressure of 400 kPa.
Determine: (a) The work done during this process, and
(b) The heat transferred.

5 moles of a monatomic ideal gas initially at 1 atm and 200 K is
compressed isothermally against a constant external pressure of 2.0
atm, to a final pressure of 2.0 atm. Calculate W; Q; U; and H in
Joules.

A quantity of air is contained in a cylinder provided
with a movable piston. Initially the
pressure of the air is 4 × 107 N/m2
, the volume is 1.5 m3
and the temperature is 400 K.
Assume air is an ideal gas. (a) What are the final volume and
temperature of the air if it is
allowed to expand isothermally from initial conditions until the
pressure is 3 × 107 N/m2
and
then is cooled at constant volume until...

A gas initially at 2.8 bar and 60ºC is compressed to a final
pressure of 14 bar in an isothermal internally reversible process.
Determine the work and heat transfer, each in kJ per kg of gas, if
the gas is (a) Refrigerant 134a, (b) air as an ideal gas. Sketch
the process on p–v and T–s coordinates

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...

Consider a cold air-standard Diesel cycle. At the beginning of
compression, 102 kPa, and 300 K. The mass of air is 0.120 kg, the
compression ratio is 16, and the cut-off ratio is 2.0
For a cold air-standard analysis use the following values: cp =
1.005 kJ/kgK, cv = 0.718 kJ/kgK, k=1.40, M=28.97 kg/kmol.
Determine the following :
(a) pressure at end of compression stroke, in kPa
(b) temperature at end of compression stroke, in K
(c) maximum temperature in...

An adiabatic air compressor compresses 10.6 L/s of air at 120
kPa and 20°C to 1000 kPa and 300°C. The constant pressure specific
heat of air at the average temperature of 160°C = 433 K is
cP = 1.018 kJ/kg·K. The gas constant of air is
R = 0.287 kPa·m3/kg·K. Determine the work
required by the compressor

A compressed air tank has a volume of 0.81 ft3. The
temperature is 70 °F and the atmospheric pressure is 14.7 psia.
When the tank is filled with air at a pressure of 46 psig,
determine the density of the air and the weight of air in the
tank.
Answer in lb

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