G determination

Each of the f2 samples had a nominal weight of O.f g. Determine the approximate value for fQ, and the mass of sample needed to achieve a percent relative standard deviation of 2%. 

Markow, P. G. Determining the Lead Content of Paint Chips, /. Chem. Educ. 1996, 73, 178-179. 

Source Values taken from Bates, R. G. Determination of pH Theory and Practice, 2nd ed. Wiley New York, 1973. Concentrations are given in molality (moles solute per kilograms solvent). 

Stannett and Szwarc have argued that the permeability is a product of a factor F determined by the nature of the polymer, a factor G determined by the nature of gas and an interaction factor H (considered to be of little significance and assumed to be unity). 

Phenylurea herbicides (urons). Dinocap, Dinoseb, Benomyl, Carbendazim and Metamitron in Waters [e.g. determination of phenylurea herbicides by reverse phase HPLC, phenylurea herbicides by dichloromethane extraction, determination by GC/NPD, phenylurea herbicides by thermospray LC-MS, Dinocap by HPLC, Dinoseb water by HPLC, Carbendazim and Benomyl (as Carbendazim) by HPLC], 1994... 

UV spectra are, however, very useful for the determination of acid-base and ion pair formation equilibria, and for photochemical investigations (e. g., determination of quantum yield in photolytic dediazoniation, Tsunoda and Yamaoka, 1966 fluorescence and phosphorescence at low temperature, Sukigahara and Kikuchi, 1967a). 

Other physical methods were also applied to the elucidation of the isomerism of diazocyanides, e. g., determination of diamagnetic susceptibility, the Faraday effect (optical rotation in a magnetic field), and electronic and infrared spectra. Hantzsch and Schulze measured ultraviolet spectra at a remarkably early date (1895 a). Unfortunately, their results and later work (Le Fevre and Wilson, 1949 Freeman and Le Fevre, 1950) did not allow unambiguous conclusions, except perhaps the observation that the molar extinction coefficients of the band at lowest frequency are consistently larger in all types of (i -compounds Ar — N2 - X than in the corresponding (Z)-iso-mers (Zollinger, 1961, p. 62). 

For the temperature dependency of Pu(g), Battles et al. (15) combined the partial pressure of Pu(g) determined at 2219 K and an assumed partial enthalpy of vaporization value of 118 kcal/mol, leading to the expression... 

To cold diionyl chloride (1.31 g, 11 mmol) in an ice-water bath, pyridine (10 mL) is added slowly for 10 min to keep the reaction temperature low. The reaction medium is stirred for 30 min. Then, a mixture of isophdialic acid (0.41 g, 2.5 mmol) and terephdialic acid (0.41 g, 2.5 mmol) in pyridine (10 mL) is added slowly for 10-20 min to control the reaction temperature. The cooling badi is then removed and the reaction mixture is stirred at room temperature for 20 min. 2,2-Bis(4-hydroxyphenyl)propane (bisphenol-A, 1.14 g, 5 mmol) in pyridine (10 mL) is added all at once to the mixture, and the whole solution is heated to 80°C (bath temperature) for 4 h. The resulting viscous solution is diluted with pyridine and poured into methanol to precipitate the polymer, which is washed in boiling methanol and dried. The inherent viscosity of polymer is 2.2 dL/g (determined in 60/40 phenol-1.1.2.2-tetrachloroethane at 30°C)... 

Note Kricheldorf et al.268 synthesized the same polyester by a similar procedure using Ti(OPr)4 as polymerization catalyst. The characteristics of the resulting polymer were inherent viscosity 0.22 dL/g (determined at 20°C in 4/1 CH2C12-trifluoroacetic acid at a concentration of 0.2 g/dL). DSC Tg = 164°C. Degree of branching (DB) 0.48 (determined by H NMR). 

C03-0150. A sample of a component of petroleum was subjected to combustion analysis. An empty vial of mass 2.7534 g was filled with the sample, after which vial plus sample had a mass of 2.8954 g. The sample was burned in a combustion train whose CO2 trap had a mass of 54.4375 g and whose H2 O trap had a mass of 47.8845 g. At the end of the analysis, the CO2 trap had a new mass of 54.9140 g and the H2O trap had a new mass of 47.9961 g. Determine the empirical formula of this component of petroleum. 

Chlorine trifluoride is used to recover uranium from nuclear fuel rods in a high-temperature reaction that produces gaseous uranium hexafluoride 2 ClF3(g)+U( ) UF(5(g)-I-Cl2(g) Determine the Lewis... 

C14-0094. One possible source of acid rain is the reaction between NO2, a pollutant from automobile exhausts, and water 3 N02(g) + H2 0(/) 2 HN03(g) + NO(g) Determine whether this is... 

Mangos, T.J. and Berger, R.G., Determination of major chlorophyll degradation products, Z. Lebensm. Unters. Forsh. A, 204, 345, 1997. 

Longo, L. and Vasapollo, G., Determination of anthocyanins in Ruscus aculeatus L. berries, J. Agric. Food Chem., 53, 475, 2005. 

Takacs-Novak, K., Avdeef, A., Box, K. J., Podanyi, B., Szasz, G. Determination of protonation macro- and microconstants and octanol/water partition coefficient of the antiinflammatory drug niflumic add. J. Pharm. Biomed. Anal. 1994, 12, 1369-1377. 

Metallic ores can vary widely in grade (% metal content). The grade of the ore, G, determines the number of tons of the ore, T, that must be processed to recover one ton of the metal. If the recovery (% metal recovered) during processing is represented by R, the terms G, T, and R are related as follows ... 

Thurl, S., Offermanns, J., Muller-Werner, B., and Sawatzki, G., Determination of neutral oligosaccharide fractions from human milk by gel permeation chromatography, /. Chromatogr., 568, 291, 1991. 

Frega, N., Bocci, F., Lercker, G., Determination of Robusta in commercial blends with Arabica coffee, Ind. Aliment. (Pinerolo, Italy), 34(339), 705, 1995. (CA123 337687u)... 

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