Micromeritics FlowSorb III 2305 Operator's Manual page 75

FlowSorb III
The result for a 30% N
when room temperature is 22
expression

S = V

 Rm.Temp.  
= V x
where S is the surface area in square meters.
For calibration purposes, this means that a syringe injection of V = 1.00 cm
nitrogen at 22 °C and 760 mmHg should produce an indicated surface area of
2
2.84 m
The value of S from equation 7 changes when ambient conditions differ signifi-
cantly from 22 °C and 760 mmHg, pressure changes having relatively more ef-
fect than temperature. Another value should then be calculated. For example,
suppose the gas were 29.33% N
sure were 710 mmHg, and the saturation pressure were measured to be 735
mmHg, the value, instead of being 2.84, should be 2.67.
Aug 00
/70% He mixture adsorbed at liquid nitrogen temperature
2
o
C and atmospheric pressure is 760 mmHg is the
 Atm.Press.  6.023x10 x16.2x10
273.2
 
 
760
 
23
273.2 760 6.023x10 x16.2x10
x x
760
295.2
22.414x10
.
 
−20
23
1 −
 
3  
22.414x10
−20
0.3x760
x 1 −
3
775
, the laboratory were at 25 °C, atmospheric pres-
2
Appendix A
(%N ⁄ 100)xAtm.Press. 
2


Sat.Press.
=
2.84 V (7)
3
of
A-3