Determine whether the ideal gas approximation is good or
reasonable or all wet for the following conditions. State exactly
why or why not.
Oxygen at 30C, 3 MPa
UNGRADED Methane at 30C, 3 MPa
UNGRADED Water at 30C, 3 MPa
R-134a at 30C, 3 MPa
R-134a at 30C, 100 kPa
A rigid tank holds
4
m of air at
6
bar and 100C. To
cool it down a bit,
2
kg of air is allowed to escape. This lowers
the temperature by 25C. What is the final pressure?
In the ideal Diesel cycle, the combustion proceeds
isobarically. Assume that the air-fuel mixture can be approximated
as plain air, and that the initial volume is 0.5
L and the final volume
1.3
L,
while the initial pressure and temperature are
7
MPa and
700C.
What is the mass of the air, and the final temperature in degrees
centrigrade?
UNGRADED (Refer to figure P3.73 / P 3.53 / P 2.80 in the book.) A rigid
tank of volume 2 m is connected by a valve to another
tank with twice the volume. Initially, tank holds nitrogen
at 100 kPa and 250 K, and tank nitrogen at 200 kPa and 300 K.
Then the valve is opened and the combined tanks come to a uniform
state at a temperature of 280 K. What is the pressure in the tanks
then?