Micromeritics 1305 Operator's Manual page 52

Appendix A
When the valve is opened, the pressure will fall to an intermediate value, P2, and
the mass balance equation becomes
Substituting from equations (1) and (2) into (3):
or
then
Adding and subtracting P
Dividing by (P
or
Since P
sures and equation (9) is arranged so that P
before use, new P
A-2
P (V - V + V
2 CELL SAMP
P (V - V + V
n CELL SAMP
(P - P )(V - V
2 1 CELL SAMP
− P
P
a
− V =
V
CELL − P
SAMP
P
2
in the denominator and rearranging gives
a
− V = −V +
( P
SAMP CELL
- P ) in both the numerator and denominator
a 2
= V −
V
SAMP CELL
−1 −
V
= V −
V
 − P
SAMP CELL
P
1

− P
P

2
, P , and P are expressed in equations (1) through (9) as absolute pres-
1 2 a
and P may be redefined as gauge pressures
1g 2g
Model 1305 MultiVolume Pycnometer
) = n RT + n RT
EXP C a E a
) = P (V - V
EXP 1 CELL SAMP
) = (P - P )V
a 2 EXP
2
V
EXP
1
(P − P ) V
a 2 EXP
− P ) − (P − P )
2
a 1 a
V
EXP
 − P 
P
1 a
 
− P
P
 
a 2
EXP

a − 1


a
is subtracted from both P
a
(3)
) + P V (4)
a EXP
(5)
(6)
(7)
(8)
(9)
and P
1 2
Jun 99