Phosphorus critical values

An example of phosphorus-loading influence on adsorption characteristics is shown in Figure 9.23. The critical value of EPCq increases with phosphorus loading, suggesting that the soil does not have enough buffering capacity to maintain low phosphorus concentration in the soil pore water or the soil solid phase has been saturated with added phosphorus therefore, phosphorus concentration in solution increases. In general, wetland soils that are heavily loaded function as net source of phosphorus, especially when these soils come in contact with low-phosphorus water (rainwater). 

A. Smits and S. C. Bokhorst calculated the value of the constant b of J. D. van der Waals equation. This when taken to represent the size of the molecule becomes 0-00539, at the critical temp. the corresponding value calculated for the phosphorus atom in phosphine is 0-00124 so that there are 0-00539/0-00124=4-33 atoms in the molecule. This is taken to indicate a slight association of the P4-mols. J. J. van Laar calculated for b of J. D. van der Waals equation, 6=0-00140 for a, Va=0-066 and for the valency attraction A, VA—33. M. Trautz calculated 20xl0 8 cm. for the molecular diameter of phosphorus. 

D. MacCrae and C. C. van Voorhis represented their measurements between 44-1° and 150° by log, p=7-9542—2757-5Z1-1 mm. L. Troost and P. Hautefeuille measured the vap. press, of liquid yellow phosphorus between 360° and 510°, and found that above 510°, the liquid was transformed so rapidly into red phosphorus that its vap. press, could not be measured. They also measured the vap. press, of red phosphorus between 360° and 577°. E. Riecke represented their values for solid red phosphorus by log10y=—45-01-f-16-28 log10 T—832jP-1 atm. and for liquid phosphorus, log10 p=—2-450+2-064 log10 T—1530 T 1 atm. P- Jolibois also measured the vap. press, of red and yellow phosphorus. A. Smits and S. C. Bokhorst gave for solid and liquid violet phosphorus from 308-5° to the critical temp., 695° ... 

Fig. 10, where the speed of the reaction, zero at 700 mm., increases rapidly as the press, falls, and then varies within narrow limits over press, ranging from about 500 mm. to about 100 mm., and finally decreases rapidly to zero, in vacuo. J. Chariton and Z. Walta found that there is a relation between the vap. press, of the phosphorus and the critical press, of the oxygen below which no oxidation occurs. The critical press, is lowered if argon be present. If the press, of the oxygen be below a critical pressure, no rapid reaction occurs. The value of the critical press, is greater the greater the press, of the phosphorus vap. Above the critical press., the reaction is extremely... 

The value of b for phosphorus in combination is obtained additively from the critical data of phosphine. For the compound b is 0-00233, and for three hydrogen atoms 3b is 0-001086, whence b for combined phosphorus (1 atom) is 0-001244. The ratio of this to b for the free element gives the atomicity, 4-33, of the latter. 

Prout did not consider himself a proficient experimentalist nonetheless, he designed and carried out experiments to determine the weights of such atoms as iodine, phosphorus, sodium, iron, zinc, potassium, and beryllium. For other elements he accepted the atomic weights that had been measured by scientists he considered trustworthy. Of critical importance was the atomic weight accepted for hydrogen itself and for this Prout used the value measured by Davy. With these data in hand, Prout pro-... 

The positive p values of these correlations for reactions of substituted phenyl phosphates may indicate a common feature in these reactions where a nucleophilic attack on phosphorus is a critical step. The magnitudes of the p values of Equations 13 and 14 are very close to each other but significantly larger than that of Equation 12. Thus, the electronic effect of the substituents on the insect mortality can be related mostly to an effect on the enzyme inhibition and plays only a minor role in the... 

A plasma PSG film was analyzed. The results, which reveal only two peaks, are shown in Figure 7. However, according to Crutchfield et al. (6), when analyzing oxoaclds of phosphorus by NMR, the pH is critical (see Figure 8). Since the original NMR solution had a pH of 3, the sample was analyzed in a basic solution. Again only two peaks were obtained whose values were Identical to those found for known solutions of phosphate and phosphite. 

This triple point is the point of intersection of the three univariant systems solid— vapour (curve FD), liquid— vapour (curve DE), solid— liquid (curve DI). The values of the vapour pressures of solid and of liquid violet phosphorus are given in the tables on pp. 60 and 61. The curve DE will end abruptly at the critical point of liquid phosphorus. The critical temperature was found by W. A. Wahl to lie at 695° C. and from the course of the vapour-pressure curve, Smits and Bokhorst have calculated that at this temperature the pressure (critical pressure) would be 82 2 atm. According to Marckwald and Helmholz, the critical temperature is 720 6 . 

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