Posted by chris on Saturday, January 15, 2011 at 10:56pm.
An air tank with a volume of 20m^3 is pressurized to 10 MPa. The tank eventually reaches room temperature of 25 degree C. If the air inside is allowed to escape without any heat transfer to the environment unit reaches a pressure of 200 KLPa, find the remaining mass of air in the tank and its temperature.

thermodynamics  drwls, Saturday, January 15, 2011 at 11:55pm
In the USA, it is customary to call the subject thermodynamics. Without the "s", the word "thermodynamic" is an adjective.
It may be different in some English speaking countries.
I do not recognize the meaning of "L" in KLPa. Do you mean KPa? (kiloPascals?)
The air inside undergoes an isentropic adiabatic expansion, and it cools off in the process. You will need to make use of the fact that the specific heat ratio (gamma = Cp/Cv) for air is 1.40.
P/(density)^1.4 is constant in the expansion process. If the pressure falls by a factor of 50, from 10 MPa to 0.2 MPa, the density decreases by a factor 50^(5/7) = 16.35
The new temperature can be deduced using the ideal gas law.
P/(density*T) = constant
T2/T1 = (P2/P1)*(density1/density2)
= (1/50)*(16.35) = 0.327
Temperature must be in Kelvin.
T2 = 130 K
Get the final mass in the tank from the final density and the volume.
Answer This Question
Related Questions
 physics  An air compressor is a device that pumps air particles into a tank. A...
 physics  An air compressor is a device that pumps air particles into a tank. A ...
 thermodynamics  A scuba tank contains 1.5 kg. of air. The air in the tank is ...
 Science  how the volume of air in a tank of compressed air would change if the ...
 Thermophysic and electromagnetisme  A tank of volume V = 2.0 l will burst if ...
 physics  I'm having a really hard time with this physics problem...not really ...
 physics  The volume of a 100 cu ft air tank at 45 psig is put in a 30 cu ft air...
 Physics  The volume of a 100 cu ft air tank at 45 psig is put in a 30 cu ft air...
 phycis  A cylindrical tank has a tightfitting piston that allows the volume of...
 fluids  An open tank holding 400 cubic foot of air at atmospheric pressure at ...
More Related Questions