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Water, determination Waters, concentrated

Bearing in mind, from the discussion above, that °Brix really only allows estimation of relative water content in a series of related systems, this measure is used sufficiently frequently to require that the procedures be outlined. The sections below describe the use of the refrac-tometer and the hydrometer for determining water concentration. These instruments are readily available from a number of sources including Brannan and ERTCO Precision (for... [Pg.29]

Vapor Pressure Measurements. Total vapor pressures were measured at 30°C with a Texas Instruments quartz spiral gauge. The procedure used was similar to that given previously (5). The concentration of water after the experiment was checked by Karl Fischer titration, while that of ether was found by weighing the cell before and after the vapor pressure determination the loss of weight was that of ether. Since Sb( V) interferes with the Karl Fischer titration of water, the water concentration in the HSbClG solutions was also obtained from the loss of weight of the cell. [Pg.152]

Two Baker solutions are described. The first contains liquid phenol USP 5 cm, distilled water 4 cm, croton oil 3 drops and septisol 5 drops. The second contains liquid phenol USP 3 cm, distilled water 2 cm, croton oil 3 drops and septisol 8 drops. The water determines the concentration, which is variable. Baker s solution has to be stirred constantly, as it is not stable and separates into layers if left to rest. [Pg.196]

Most solutes are present at fairly low concentrations (< 0.1 M) and water is present at high concentration (55.6 M for pure water) the water concentration is thus assumed to be constant. If water enters into a reaction, it is incorporated into K q, if K q is determined at pH 7.0, it is indicated by K. ... [Pg.70]

Karl Fischer Titration -ASTM D6304 The Karl Fischer titration, KFT, method determines water concentration by titrating a measured amount of sample and Karl Fischer reagent. The reagent reacts with the OH molecules present in the moisture, and present in other compounds, and depolarizes an electrode. The corresponding potentiometric change is used to determine the titration end point and calculates the concentration value for water. KFT reagents include iodine, methanol and chloroform and thus require a separate waste stream due to the chloroform. [Pg.486]

Benzylpenicillin is an older antibiotic effective against pneumococcal and meningoccal infections, anthrax, and Lyme disease. As part of a purification process. 200 mg of benzyipenicillin is mixed with 25 mL of n-octmol and 25 mL of water. After equilibrium is established, there is a water-rich phase that contains essentially no /t-octanol and ati octanol-rich phase that contains 74. mol % n-octanol and 26 mol % water. Determine the concentrations of benzyipenicillin in each of these phases. [Pg.643]

Water containing 2 oz of pollutant/gal flows through a treatment tank at a rate of 500gal/min [7]. hi the tank, the treatment removes 2% of the pollutant per min and the water is thoroughly stirred. The tank holds 10,000 gal of water. On the day the treatment plant opens, the tank is filled with pure water. Determine the concentration profile of the tank effluent. [Pg.35]

Q6 11 mg of sulfuric acid are added to 2 kg of water. Determine the concentration of sulfuric acid in ppm. [2]... [Pg.51]

The small molecule literature has some precedent for hydrolysis reactions under pH neutral conditions to be second order in water [18-21]. The hydrolysis mechanism requires some catalytic species either to polarize the carbonyl group or to aid in moving a proton from one oxygen to another. In the absence of added catalyst, as would be the case for a clean polymer, another molecule of water serves this purpose. We can think of condensation polymer hydrolysis as a water-catalyzed hydrolysis. Since two molecnles of water are required in the rate-determining step (one as the reactant and one as the catalyst), the kinetics are second order in water. The water concentration in the polymer is proportional to the RH, so the kinetics are second order in RH. [Pg.48]

The hydrolysis by alkali is illustrated by the following experimental details for benzamido. Place 3 g. of benzamide and 50 ml. of 10 per cent, sodium hydroxide solution in a 150 ml. conical or round-bottomed flask equipped with a reflux condenser. Boil the mixture gently for 30 minutes ammonia is freely evolved. Detach the condenser and continue the boiling in the open flask for 3-4 minutes to expel the residual ammonia. Cool the solution in ice, and add concentrated hydrochloric acid until the mixture is strongly acidic benzoic acid separates immediately. Leave the mixture in ice until cold, filter at the pump, wash with a little cold water and drain well. RecrystaUise the benzoic acid from hot water. Determine the m.p., and confirm its identity by a mixed m.p. test. [Pg.799]

Suppose you are asked to develop a way to determine the concentration of lead in drinking water. How would you approach this problem To answer this question it helps to distinguish among four levels of analytical methodology techniques, methods, procedures, and protocols. ... [Pg.36]

Analysis of water from a drinking fountain gives areas of f.56 X i0 5.f3 X i0 f.49 X fOk and f.76 X fO- for GHGI3, GHGl2Br, GHGlBr2, and GHBr3, respectively. Determine the concentration of each of the trihalomethanes in the sample of water. [Pg.616]

Determine the concentration of each ion in the sample of rain water, (c) The detection of HC03 actually gives the total concentration of carbonate in solution ([C03 ]... [Pg.618]

Transport and Transformation. Once emitted into the atmosphere, the fate of a particular poUutant depends upon the stabihty of the atmosphere, which determines the concentration of the species, the stabihty of the poUutant in the atmosphere, which determines the persistence of the substance. Transport depends upon the stabUity of the atmosphere which, in turn, depends upon the ventilation. The stabUity of a poUutant depends on the presence or absence of clouds, fog, or precipitation the poUutant s solubUity in water and reactivity with other atmospheric constituents (which may be a function of temperature) the concentrations of other atmospheric constituents the poUutant s stabUity in the presence of sunlight and the deposition velocity of the poUutant. [Pg.367]

As httle as lO " g of ATP can be detected with carefiiUy purified luciferase. Commercial luciferase contains enough residual ATP to cause background emission and increase the detection limit to 10 g (294). The method has been used to determine bacterial concentrations in water. As few as lO" cells/mL of Lscherichia coli, which contains as Httle as 10 g of ATP per cell, can be detected (294). Numerous species of bacteria have been studied using this technique (293—295). [Pg.275]

The identification of benzene is most easily carried out by gas chromatography (83). Gas chromatographic analysis of benzene is the method of choice for determining benzene concentrations in many diverse media such as petroleum products or reformate, water, sod, air, or blood. Benzene in air can be measured by injection of a sample obtained from a syringe directiy into a gas chromatograph (84). [Pg.46]

Therefore, the amount of water present determines the concentration of N02 and hence the extent of nitration. The degree of cellulose nitration is designated by the nitrogen content. The maximum commercial DS is 2.9, which corresponds to 13.8% N. Products over 14% N have been obtained by special processes (51—54). [Pg.265]

DETERMINATION OF CONCENTRATION OF ORGANOCHLORINE INSECTICIDES IN DRINKING WATER OF SERBIA... [Pg.227]

IQ. To determine the concentration of chloride ion, - a 5-mL aliquot of the methyl lithium solution is cautiously added to 25 ml of water and the resulting solution is acidified with concentrated sulfuric acid and then treated with 2-3 ml of ferric ammonium sulfate [Fe(NH4)( 04)2 12 H2O] indicator solution and 2-3 ml of benzyl alcohol. The resulting mixture is treated with 10.0 mL of standard aqueous 0.100 M silver nitrate solution and then titrated with standard aqueous 0.100 H potassium thiocyanate solution to a brownish-red endpoint. [Pg.106]

Mass concentration units for ambient measurements are mass (/xg) per unit volume (m ). Size classification involves the use of specially designed inlet configurations, e.g., PMjq sampling. To determine mass concentration, all the particles are removed from a known volume of air and their total mass is measured. This removal is accomplished by two techniques, filtration and impaction, described in Chapter 13. Mass measurements are made by pre-and postweighing of filters or impaction surfaces. To account for the absorption of water vapor, the filters are generally equilibrated at standard conditions T = 20°C and 50% relative humidity). [Pg.204]

The relative importance of the potential catalytic mechanisms depends on pH, which also determines the concentration of the other participating species such as water, hydronium ion, and hydroxide ion. At low pH, the general acid catalysis mechanism dominates, and comparison with analogous systems in which the intramolecular proton transfer is not available suggests that the intramolecular catalysis results in a 25- to 100-fold rate enhancement At neutral pH, the intramolecular general base catalysis mechanism begins to operate. It is estimated that the catalytic effect for this mechanism is a factor of about 10. Although the nucleophilic catalysis mechanism was not observed in the parent compound, it occurred in certain substituted derivatives. [Pg.492]

The facility wastewater monitoring program does not determine the concentration of lead and lead compounds in the scrubber discharge water, and releases to the surface impoundment (releases to land) must be calculated using mate-riai balance information. These releases to land are determined from the amount of lead removed by the scrubber (using the efficiency data provided by the scrubber manufacturer). The volume of the scrubber blowdown Is found to be 1,500 pounds per year. Enter the estimate of the amount of lead and lead compounds released to surface Impoundments in the space provided in Part III, Section 5.5.3 of the form. Because releases of lead to the surface Impoundment are greater than 999 pounds per year, you must enter the actual calculated amount in column A.2 of Section 5.5.1. The basis for the estimate of releases to the surface impoundment, entered in column B of Section 5, is mass balance calculations (code C). [Pg.84]

The efficiency of water separation varies considerably from boiler to boiler. The purity of the steam supplied to a steam turbine should be checked. On the basis of the results, the maximum allowable salt concentration in the boiler water can be determined. This concentration may be much lower than the values given in the table. [Pg.159]

Gas velocity is measured over an aperture in the heated zone of the sampling train, at a temperature of 110 °C, to remove the moisture by heating. Determine the gas velocity at the sampling nozzle if the measured velocity is 28 m s for the sampling diameter used. The water concentration determined from the condensate is 75 g m" (n). [Pg.1284]

CENGAGENOW Acid-base reactions in water solution are commonly used to determine the concentration of... [Pg.84]

The reverse of Example 16.4 involves finding Rq, of a compound given its solubility. The solubilities of many ionic compounds are determined experimentally and tabulated in chemical handbooks. Most solubility values are given in grams of solute dissolved in 100 grams of water. To obtain the molar solubility in moles/L, we have to assume that the density of the solution is equal to that of water. Then the number of grams of solute per 100 g water is equal to the number of grams of solute per 100 mL of solution. This assumption is valid because the mass of the compound in solution is small. To solve for IQp, find the molar solubility of the solute and determine the concentration of its component ions. Substitute into the IQp expression. [Pg.436]


See other pages where Water, determination Waters, concentrated is mentioned: [Pg.42]    [Pg.277]    [Pg.36]    [Pg.38]    [Pg.45]    [Pg.156]    [Pg.368]    [Pg.396]    [Pg.431]    [Pg.441]    [Pg.457]    [Pg.362]    [Pg.440]    [Pg.176]    [Pg.6]    [Pg.288]    [Pg.1164]    [Pg.153]    [Pg.174]    [Pg.141]    [Pg.133]    [Pg.19]    [Pg.856]    [Pg.402]   


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