Relative Pressure Calculations; Equation Of State - Micromeritics ASAP 2460 Operator's Manual

Appendix C

Relative Pressure Calculations

If Po is measured in the Po tube, the current pressure is measured in the Po tube when each point is
taken, and used to calculate relative pressure for that point:
P
------ -
P =
rel
Po

Equation of State

The ideal gas law relates pressure, volume, temperature, and quantity of gas.
where
P =
R =
T =
V =
z =
The real gas equation of state
PV
------------------------ -
n =

RTz P T
C-2
pressure
a constant that depends on the units of n
3 R
For n in cm , STP
For n in moles, R = 8.3145 J mol
temperature
volume
compressibility factor for the gas at the given pressure and temperature
 
P
STD
------------
=
T
STD
-1 -1
K
ASAP 2460 Operator's Manual
246-42800-01 - Aug 2013