Transcript week3-fPAL.ppt

PAL 3/23/12
1.
Consider a gas held at constant temperature as the pressure is increase
without limit (to infinity).
a) What happens to the specific volume of the gas, according to the ideal
gas law?
b) Does this make sense? (Hint: Is there room for the molecules?)
2.
Consider a gas held at constant temperature.
a) Suppose the volume is such that the molecules are 1 m apart.
According to the ideal gas law, by how much do you need to increase
the pressure in order to decrease the volume by half?
b) Suppose the volume is such that the molecules are 1 mm apart.
According to the ideal gas law, by how much do you need to increase
the pressure in order to decrease the volume by half?
c) Does this make sense? If not, which of the above processes should
require a greater pressure increase? (Hint: Which should be harder to
compress?) For this question, ignore the finite size of the molecules
(we dealt with that in #1), and just consider their interactions.
3.
A system consisting of CO2 gas is at a temperature of 20oC and a
molar volume of 10-4 m3/mole. Calculate the pressure, using…
a)
b)
c)
d)
Ideal gas law.
Beattie-Bridgeman eos.
Benedict-Webb-Rubin eos.
Assuming that your answer to (c) is most accurate, find the percent
error in (a) and (b).