Question

0.5 kilograms of air are compressed from 100 kPa and 300 K in a
polytropic process, n = 1.3, to a state where V_{2} = 0.5
V_{1}. The air is further compressed at constant pressure
until the final volume is 0.2 V_{1} . Draw a sketch of the
processes on a p-V diagram. Determine the work for each
process.

Answer #1

In this problem, first of all draw the process on the P-V diagram then calculate pressure and Volume at each state and then calculate the work for both process as below:

Note:- The negative sign shows that the work done on the system.

Two kilograms of air undergo a polytropic process (n = 1.3) from
600 K and 200 kPa to 900 K. Considering the system and surroundings
as an isolated system, find the entropy change of the air and the
entropy production.
Answers: -0.1938 kJ/K, 0.284 (Engineering Thermodynamics)

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)...

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

Air expands in a polytropic process (n = 1.35) from 2 MPa and
1200 K to 150 kPa in a piston/cylinder. Determine per
unit mass of air the work produced and the heat transferred during
the expansion process in kJ/kg.

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...

An ideal gas with γ=1.4 occupies 5.0 L at 300 K and 120 kPa
pressure and is heated at constant volume until its pressure has
doubled. It's then compressed adiabatically until its volume is
one-fourth its original value, then cooled at constant volume to
300 K , and finally allowed to expand isothermally to its original
state.
Find the net work done on the gas. W= ___J

One mole of air is compressed from pressure P1 and temperature
T1 at
constant volume till its pressure is doubled. Then it is
expanded
reversibly and isothermally to the original pressure, and finally
restored
to the original temperature by cooling at constant pressure. Sketch
the
path followed by the gas, on a P-V diagram and calculate the net
work
done by the gas.

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.

A 0.2 m3 piston/cylinder contains air at 400 K and
400 kPa and receives heat from a constant temperature heat source
at 1300 K. The piston expands at constant pressure to a
volume of 0.6 m3. Determine the change of availability
of the system.

1. Methane and oxygen exist in a stoichiometric mixture at 500
kPa and 298 K. They are ignited and react at constant volume.
Combustion is complete. The final products are at 1500 K.
a. If the reaction above occurs in an insulated container, find
the final temperature and pressure of the products.
b. If the same mixture reacts at constant pressure, find the
final temperature.
c. Suppose the products from both #2 and #3 then undergo
adiabatic expansion in a...

ADVERTISEMENT

Get Answers For Free

Most questions answered within 1 hours.

ADVERTISEMENT

asked 59 seconds ago

asked 1 minute ago

asked 4 minutes ago

asked 4 minutes ago

asked 4 minutes ago

asked 12 minutes ago

asked 12 minutes ago

asked 16 minutes ago

asked 16 minutes ago

asked 18 minutes ago

asked 18 minutes ago

asked 20 minutes ago