Calculating The Result - Micromeritics FlowSorb III 2305 Operator's Manual

FlowSorb III

Calculating the Result

Appendix A gives the basic theory and pertinent equation of the multipoint calcu-
lation. Table 3.3 formalizes the procedure beginning on the left and proceeding to
the right using the experimental data in Table 3.2.
Experimental Data
Gas
Composition
4.999
9.997
14.993
22.006
(*) (%N
A plot of the sixth versus the third column is given by Figure 3.2. The slope of
the plotted line is 0.0560 and the intercept is 0.0008. From equation 10 of Appen-
dix A, the sample specific surface area (S) is thus calculated as
Mar 2012
Table 3.3. Example Bet Calculation
(*) P/Po
Specific Gas
Volume (V)
15.16 0.0490
17.39 0.0980
19.16 0.1471
21.46 0.2158
/100) x 760/775 = (%N
2
4.353
S =
0.0560 + 0.0008
Performing a Multipoint Surface Area Measurement
1-(P/Po) V[1-(P/Po)]
0.9510 14.42
0.9020 15.69
0.8529 16.34
0.7842 16.83
/100) x 0.981 = %N x 0.00981
2 2
2
= 76.6 m /g
(P/Po)/V[1-(P/Po)]
0.00340
0.00625
0.00900
0.01282
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