Micromeritics ACCUPYC II 1345 Operator's Manual page 192

E Sample Volume Equation Derivation
where
P = ambient pressure
a
n = moles of gas in the expansion volume
x
When the valve is opened, the pressure falls to an intermediate value, P
Substituting from equations (1) and (2) into (3):
or
then
Adding and subtracting P
Dividing by (P - P ) in both the numerator and denominator
a 2
or
E - 2
in the denominator and rearranging gives
a
, and mass balance yields:
2
AccuPyc II 1345 Operator Manual
134-42851-01 (Rev -) — Not Released
(3)
(4)
(5)
(6)
(7)
(8)
(9)