Nitrogen and argon

The survey in the present section shows quite clearly that it is not possible to assign a fixed value of a to a given adsorptive, which will remain valid for its adsorption on ail adsorbents. As demonstrated in Section 2.7, nitrogen and argon would seem to provide the best approximation to a constant effective molecular area, with = 16-2 A and a, (Ar) = 16-6 A. ... 

In view of the widespread use of nitrogen and argon in surface area and porosity studies, data for the construction of the standard a,-curves for these adsorbates on hydroxylated silica, are given in Table 2.14 (p. 93) for nitrogen and in Table 2.15 for argon. From the arguments of Section 2.12, these should be adequate for other oxides such as alumina, if high accuracy is not called for. 

SmitJisonian Tables, Table 269. For a detailed discussion of mercury data, see Cook, Biit. J. Appl. Fhys., 7,285 (1956). For data on nitrogen and argon, see Johnson (ed.), WADD-TR-60-56, 1960. 

Flue gas rate (dry basis) is calculated from the dry air rate using nitrogen and argon as tie elements. 

FIG. 12. Measured Paschen law for silane, hydrogen, nitrogen, and argon. (Redrawn from K. M. H. Maessen, Ph.D. Thesis. Universileit Utrecht. Utrecht, the Netherlands. 1988. with permission.)... 

Elastomers function as a barrier to either moisture or atmospheric gases (oxygen, nitrogen, and argon). This property is important in maintaining product integrity for lyophilized or liquid products subject to decomposition by water vapor or oxygen. 

As the molar masses of oxygen, nitrogen and argon are so similar, we can approximate the mole fractions of the gases to their percentage compositions. 

J. P. Perchard and Z. Mielke, Anharmonicity and hydrogen bonding I. A near infrared study of methanol trapped in nitrogen and argon matrices. Chem. Phys. 264, 221 234 (2001). 

Marty B, Humbert F (1997) Nitrogen and argon isotopes in oceanic basalts. Earth Planet Sd Lett 152 101-112... 

FIG. 9.5 A log-log plot of d versus p for xenon, krypton, and argon on zirconium and nitrogen and argon on Pyrex. (Redrawn with permission from J. P. Hobson, Physical Adsorption at Extremely Low Pressures. In The Solid-Gas Interface, Vol. 1 (E. A. Flood, Ed.), Marcel Dekker, New York, 1967.)... 

The following data give the volume at STP of nitrogen and argon adsorbed on the same nonporous silica at -196°C t... 

Fig. 3.38. Absorption of N2-Ar in the fundamental band of N2 [111]. Nitrogen and argon densities were both 19 amagat room temperature measurement ( ) the solid line represents a fit based on the stick spectrum and a J-independent quadrupole transition moment. In pure nitrogen, an almost identical spectrum was obtained.

Equation 5 is analogous to Eq. 2 discussed above. As illustrated in Figure 4b, the mesopore size distributions determined from nitrogen and argon adsorption data were essentially the same, when calculations were carried out for adsorption branches of isotherms using the corresponding KJS-calibrated relations (Eqs. 2 and 5) [18]. 

Fig. 4. Minimum requirements for a gas chromatographic system include (I) a column which contains the substrate or stationary phase. 12) a supply nt inert carrier gas (moving phase) which is continually passed through the columns. (3) a means lor maintaining pressure and flow constant. (4) a means of admitting or injecting the sample into die carrier gas stream. (5) a detector which senses the sample components as they elute, and >) a display (recorder). The carrier gas may be any gas that does not react with the sample nr adversely artect the detector. Helium, hydrogen, nitrogen, and argon are often used...

---