Lowest molecular

Fig. XI-5. Adsorption isotherm from Ref. 61 for polystyrene on chrome in cyclohexane at the polymer theta condition. The polymer molecular weights x 10 are (-0) 11, (O) 67, (( )) 242, (( )) 762, and (O) 1340. Note that all the isotherms have a high-affinity form except for the two lowest molecular weights.

Di(hydroxyall l) Peroxides. The lowest molecular weight member of this group (2, X = Y = OH), di(hydroxymethyl) peroxide (R = R = OH) is a dangerously explosive soHd. With increasing molecular weight, di(hydroxyalkyl) peroxides become Hquids and eventually soHds of... 

Polyethers prepared from propylene oxide are soluble in most organic solvents. The products with the highest hydroxyl number (lowest molecular weight) are soluble in water, not in nonpolar solvents such as hexane. The solubihty of 3000 molecular weight triols is high enough in solvents such as toluene, hexane, and methylene chloride that the triols can be purified by a solvent extraction process. 

Each class of UF products contains certain amounts of unreacted urea. MDU/DMTU compositions, the lowest molecular-weight distribution, contain the highest amount of unreacted urea nitrogen, and ureaform contain the least amount. 

Whereas oxaziridine and diaziridine were partial subjects of comprehensive theoretical studies on cyclic compounds (73MI50800), diazirine and some of its simple derivatives were the special target of quantum chemical investigations. Since diazirine, the lowest molecular weight heterocycle, has only five atoms and is of high symmetry, there was a chance for ab initio calculations, which followed some semiempirical studies. 

Esters — These are not very reactive. Only the lowest molecular weight esters have appreciable solubility in water (e.g., ethyl acetate, 8%). Methyl and ethyl esters are more volatile than the corresponding unesterified acids. Most common esters are flammable. Esters are often easily recognizable due to their sweet to pungent odors. 

From the data in Table 5 it can be seen that the CMC depends on the type of surfactant and, within a series of similar or homologous compounds, on the chain length, i.e., molecular weight of the compound. For the three AOS compounds it is seen that the CMC of the lowest molecular weight product is about twice the value of the other two products. The CMC values of the commer-... 

An interesting observation was made in regard to the polymeriza-bility of N-acylhydroxyproline derivatives The monomers with the smallest protecting groups such as N-acetyl and N-pivaloylhydroxy-proline gave rise to the polymers with the lowest molecular weights (Table 1). When these monomers were polymerized, the initially... 

Fractional extraction occasionally is employed. The polymers of lowest molecular weight are extracted first from the sample, which is... 

These opposing tendencies may defeat the purpose of the fractional precipitation process. The fractional precipitation of crystalline polymers such as nitrocellulose, cellulose acetate, high-melting polyamides, and polyvinylidene chloride consequently is notoriously inefficient, unless conditions are so chosen as to avoid the separation of the polymer in semicrystalline form. Intermediate fractions removed in the course of fractional precipitation may even exceed in molecular weight those removed earlier. Separation by fractional extraction should be more appropriate for crystalline polymers inasmuch as both equilibrium solubility and rate of solution favor dissolution of the components of lowest molecular weight remaining in the sample. 

The lowest molecular weight observed for all polymers prepared in this study was for copolymer 16, a copolymer prepared using 75 mole % cyclohexyl methyl and 25 mole % phenyl methyl silane. The low molecular weight observed for this copolymer may be due to the two bulky side groups of the monomers (phenyl and cyclohexyl) sterically interfering with propagation during the polymerization. 

The basic refining tool is the common distillation unit. It is usually the first process in refining crude oils. Crude oil normally begins to vaporize at a temperature somewhat less than what is required to boil water. Hydrocarbons with the lowest molecular weight vaporize at the lowest temperatures, whereas successively higher temperatures are applied to separate or distill the larger molecules. 

You can rule out choice B, hydrogen peroxide, and choice C, water, because the very strong hydrogen bonds between their molecules lower the vapor pressure (the ease at which the liquid evaporates). Although answer A, carbon tetrachloride, the only nonpolar molecule in the list, has only dispersion forces present between molecules, choice D, dichloromethane, has the lowest molecular weight and consequently the lowest amount of dispersion forces. 

It is important to realize that this is a theoretical concept and no such gas actually exists. Hydrogen comes the closest to being a perfect gas as it has the lowest molecular weight. In practice, most commonly used anaesthetic gases obey the gas laws reasonably well. 

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