Moles, term explained

The pressure behavior shown in Figure 4-3 is readily explained in terms of the kinetic theory of gases. There is so much space between the molecules that each behaves independently, contributing its share to the total pressure through its occasional collisions with the container walls. The water molecules in the third bulb are seldom close to each other or to molecules provided by the air. Consequently, they contribute to the pressure exactly the same amount they do in the second bulb—the pressure they would exert if the air were not present. The 0.0011 mole of water vapor contributes 20 mm of pressure whether the air is there or not. The 0.0050 mole of air contributes 93 mm of pressure whether the water vapor is there or not. Together, the two partial pressures, 20 mm and 93 mm, determine the measured total pressure. 

The same result can be obtained from an application of Euler s theorem, explained in more detail in Appendix 1. The thermodynamic quantities, Z, are homogeneous functions of degree one with respect to mole numbers.c At constant T and p, one can use Euler s theorem to write an expression for Z in terms of the mole numbers and the derivatives of Z with respect to the mole numbers. The result isd... 

C14-0057. Using tabulated values of °, calculate the standard entropy per mole of atoms for Ar, O2, O3, and C2 Hg. Explain the trend that you find in terms of what bond formation does to atomic constraints. 

Rat oncomodulin, a parvalbumin-1 ike tumor protein that has two tyrosine residues but no tryptophan, exhibits fluorescence emission at 301 and 345 nm.(135) Upon binding two moles of Ca2+ per mole of oncomodulin, the 301-nm intensity increases while the 345-nm band decreases. These results were explained in terms of acidic side chains involved in either binding Ca2+ or accepting a proton on excited-state generation of tyrosinate. The cloned... 

Better fits were obtained for n = 1 which gave linear reduced rate-conversion plots up to 20-30 % conversion, followed by a downward curvature. The apparent preexponential factors and activation energies associated with Kt and K2 were A, = 6.53 x 10s s-1, E, = 80.4kJ/mole, A2 = 3.01 x 10s s 1, and E2 = 71.3 kJ/mole. These kinetics can be explained in terms of a bimolecular rate-determining step between hydroxylic catalyst species and either amine or a rapidly-formed amine-epoxide adduct. An analysis similar to that of Horie et al. yields the kinetic Eq. 

Explain what a mole is in terms of the number involved. 

In many solutions strong interactions may occur between like molecules to form polymeric species, or between unlike molecules to form new compounds or complexes. Such new species are formed in solution or are present in the pure substance and usually cannot be separated from the solution. Basically, thermodynamics is not concerned with detailed knowledge of the species present in a system indeed, it is sufficient as well as necessary to define the state of a system in terms of the mole numbers of the components and the two other required variables. We can make use of the expressions for the chemical potentials in terms of the components. In so doing all deviations from ideal behavior, whether the deviations are caused by the formation of new species or by the intermolecular forces operating between the molecules, are included in the excess chemical potentials. However, additional information concerning the formation of new species and the equilibrium constants involved may be obtained on the basis of certain assumptions when the experimental data are treated in terms of species. The fact that the data may be explained thermodynamically in terms of species is no proof of their existence. Extra-thermodynamic studies are required for the proof. 

An alloy named 45 Permalloy contains 54.7% Fe, 45% Ni, and 0.3% Mn by mass, (a) Express the content of a 0.685-g sample in terms of moles each metal, (b) If the source of the information had expressed the percentage composition of Permalloy in moles, rather than mass, would the 45 (percent nickel) in the name still be correct Explain. 

However, reaction of the 4-aryl-1,3-dithiolylium salts (48) with 2 moles of potassium O-ethyl dithiocarbonate in acetone produces the thioether (49) instead of the expected adduct, a result which has been explained in terms of the different solvation effect of the nucleophile in acetone and acetonitrile (77JOC1543). The reaction is reversed by treatment of (49) with perchloric acid. 

When we determine values of 7 for benzene rings attached to polymers, we find that they are much shorter than for benzene itself they are in fact at the lower limit of usefulness of the direct method. We have found (3) that for the phenyl resonance of a low molecular weight polystyrene in carbon disulfide 7 is only about 0.4 0.1 sec. at 25°. For the backbone protons, 7 is even shorter and cannot be measured by the direct method. For the phenyl groups of poly-y-benzylglutamate in trifluoroacetic acid, 7 is 0.7 0.1 sec. Recently, more reliable values have been obtained for polystyrene by the spin echo method (72). For a polymer of molecular weight 63000 in tetrachloroethylene, three 7 X values could be resolved. At 25°, these were 0.033 sec. for the aliphatic protons, 0.076 sec. for the ortho protons and 0.20 sec. for the meta-para protons. The temperature coefficients for all three Tt values correspond to a heat of activation of about 3 kcal/mole. The differences in the absolute Tx values at the aromatic positions can be explained in terms of of differences in the sums of r e in equation (56). The shorter aliphatic Tj value probably reflects also a longer correlation time for backbone... 

In this same vein, the synthesis of 25m and 2621) has been attempted by initial formation of the cyclic sulfides, then extrusion of sulfur by irradiation in the presence of triethylphosphite. In both cases the limited sample size precluded formation of the desired cyclophanes (25 and 26) by this photolytic procedure. Variable temperature H NMR studies have been performed on 27 and 28 27 has a barrier to conformational inversion of 12.5 kcal/mole, while 28 has a corresponding barrier of 10.4 kcal/mole. Phane 28 exhibits a shift of the aromatic protons to higher field as compared to 29 the most dramatic shift is observed for H-3, which absorbs at 7.72 ppm for 28 and at 8.37 ppm for 29. This shift has been explained in terms of an approximately syn orientation of the pyridine rings in 28. 

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