Concentrated solutions defined

The only clearly defined crystalline compositions are three forms of phosphoric acid and hemihydrate, pyrophosphoric acid, and crystalline P O q. The phosphoric acids obtained in highly concentrated solutions or by mixing phosphoric acid with phosphoms pentoxide are members of a continuous series of amorphous (excluding [Y OO]) condensed phosphoric acid mixtures. Mixtures having more than 86% P2O5 contain some cyclic metaphosphoric... 

Camphene forms a well-defined nitrite, and a nitroso-nitrite, when treated in the following manner A well-cooled solution of camphene in petroleum ether is mixed with a saturated solution of sodium nitrite, and dilute acetic acid is added. The mixture is well stirred, being kept cool all the time. Camphene nitrosonitrite, CuHi NjOj, separates and on recrystallisation forms crystals which decompose at about 149°. The petroleum ether solution, which has been filtered off from this compound, is shaken with a concentrated solution of pK)tassium hydroxide, which removes camphene nitrosite, CjQHigNjOj, in the form of its potassium salt. When this is decomposed with acids it yields the free nitrosite. This compound is a greenish oil, with a pleasant odour, easily decomposing when heated to 50°. 

Molal boiling point constant, 269,270t Molal freezing point constant, 269,270t Molality (m) A concentration unit defined as the number of moles of solute per kilogram of solvent, 259,261-262 Molar mass The mass of one mole of a substance, 55,68-68q alcohol, 591 alkane, 591... 

When a solute is added to an acidic solvent it may become protonated by the solvent. If the solvent is water and the concentration of solute is not very great, then the pH of the solution is a good measure of the proton-donating ability of the solvent. Unfortunately, this is no longer true in concentrated solutions because activity coefficients are no longer unity. A measurement of solvent acidity is needed that works in concentrated solutions and applies to mixed solvents as well. The Hammett acidity function is a measurement that is used for acidic solvents of high dielectric constant. For any solvent, including mixtures of solvents (but the proportions of the mixture must be specified), a value Hq is defined as... 

Because hydronium concentrations usually involve negative powers of ten, chemists use a negative log scale in expressing these concentrations. Equation defines the pH scale of acid concentration pH = - log [H3 O ] The pH of a solution is obtained by taking the logarithm of the hydronium ion concentration and then changing the sign. For example, the pH of pure water is pH = - log [H3 O ] = - log (1.0 X 10 ) — -(-7.00) — 7.00 The reverse conversion from pH to [H3 O ] uses powers of 10. For example, lemon juice has a pH of about 2.0 ... 

Note that the solution is in terms of amounts Xp rather than observed plasma concentrations Cp. The conversion from amounts to concentrations is defined by means of ... 

In homogeneous reactions, the upper limits of concentration are determined by the (limited) solubility of the salts of periodic acid and by the low pH values produced by periodic acid itself. Apart from these considerations, the concentration conditions to be selected are governed by the type of information desired. A very dilute solution having a high oxidant substrate ratio is used in the exploratory or preliminary phase defined earlier (see p. 13), but a more concentrated solution, in which the oxidant is only slightly in excess of the theoretical, is recommended for the preparative phase. 

Activity concentration is defined as the amount of radioactivity per unit volume (mCi/mL) of a sample. A 10 mL solution containing 42 mCi radioactivity will have a concentration of 4.2 mCi/mL. The majority of radiopharmaceuticals are liquids, and, therefore, the amount of radioactivity per volume (or... 

In a typical experiment, the sample is a solution (e.g., in benzene) of both the ferf-butoxyl radical precursor (di-tert-butylperoxide) and the substrate (phenol). The phenol concentration is defined by the time constraint referred to before. The net reaction must be complete much faster than the intrinsic response of the microphone. Because reaction 13.23 is, in practical terms, instantaneous, that requirement will fall only on reaction 13.24. The time scale of this reaction can be quantified by its lifetime rr, which is related to its pseudo-first-order rate constant k [PhOH] and can be set by choosing an adequate concentration of phenol, according to equation 13.25 ... 

The main equations used to extract thermochemical data from rate constants of reactions in solution were presented in section 3.2. Here, we illustrate the application of those equations with several examples quoted from the literature. First, however, recall that the rate constant for any elementary reaction in solution, defined in terms of concentrations, is related to the activation parameters through equations 15.1 or 15.2. 

For concentrated solutions, the activity coefficient of an electrolyte is conveniently defined as though it were a nonelectrolyte. This is a practical definition for the description of phase equilibria involving electrolytes. This new activity coefficient f. can be related to the mean ionic activity coefficient by equating expressions for the liquid-phase fugacity written in terms of each of the activity coefficients. For any 1-1 electrolyte, the relation is ... 

In Table 4, an overview is presented of the different experimental parameters of the CE analyses that are included in the analytical instructions part of the specific monographs mentioned above. Notice that the first 13 parameters (from capillary dimensions up to system suitability tests ) are those described in the FDA draft guidance for industry described in paragraph II From this overview it can be concluded that most experimental parameters required by the draft guidance are included in the specific monographs, currently published in the Ph.Eur. and USP. In the monograph for erythropoietin concentrated solution the injection parameters are not included. Only the injection mode (pressure or vacuum) is defined. Instead,... 

Consider a dilute ideal solution of the solute B (which could be gaseous, liquid, or solid at the temperature in question) in the solvent A. Suppose that more concentrated solutions do not behave ideally and, in particular, the state of pure liquid B cannot be attained by going to more and more concentrated solutions (e.g., by removing A by volatilization). It is possible to define a standard chemical potential pertaining to a hypothetical standard state of the ideal infinitely dilute solution as the limit ... 

The activity of an electrolyte or ion is defined for use in determining true (actual as opposed to theoretical) equihbrium constants. By definition, the activities are equal to the concentrations in very dilute solutions, and the difference between activities and concentration in more concentrated solutions depends on interaction between all the components of the solution, causing the ions to behave differently than they would at a high degree of dilution. 

After the addition of the seed crystals the relative solution concentration was periodically measured. In Figure 3 the changes of L-threonine concentration in the solution were compared for four experimental runs with different initial supersaturations. Here the relative concentration is defined as the ratio of L-threonine to the total enantiomers. For the case of lower initial supersaturations... 

The sensitivity of the detector (Xd) (or minimum detectable concentration) is defined as that concentration of solute that will provide a signal equivalent to twice the noise level. Now the concentration of solute at the peak maximum is approximately twice the average concentration of the solute in the peak, volume. Thus, the minimum detectable mass will be that mass (m) that, when dissolved in a volume of mobile phase equivalent to the peak volume, will produce a concentration of Xp/2. 

The octanol-water partition coefficient of a solute, defined as its concentration in the octanol-rich phase over its concentration in the water-rich phase at infinite dilution, is one interesting example of a liquid-liquid equilibrium coefficient. 

The FDA defines maltodextrin (C5Hi2O5)n 0 (CAS. Reg. No. 9050-36-6) as nonsweet, nutritive saccharide polymers that consist of D-glucose units linked primarily by alpha-1-4 bonds and that have dextrose equivalence (DE) less than 20. They are prepared as white powders or concentrated solutions by partial hydrolysis of corn starch with safe and suitable acids and/or enzymes (48FR51911, Nov. 15, 1983). 

From the stationary state approximation, d[A ]/dt <= 0 and d[A ]/dt = 0, the expressions for the steady state concentration of [A ] and [A ] can be set up. We can further define, 6m, and as quantum efficiencies of emission from dilute solution, from concentrated solution with quenching, and of excimer emission, respectively ... 

Concentrated solutions (c > ca. 0.25 gm/ml) show similar behavior, although with characteristic molecular weights that increase with concentration. In many systems the transition remains fairly well defined and, within the accuracy of the data, conforms to... 

Figure Seven (7) depicts a general schematic for membrane processes. In these technologies the implication of increasing the dewatering process is described by the term "recovery", which is defined as the purified water volume divided by the incoming stream volume in other words, percentage of the feed flow which is pumped through the membrane. Typically, for effluent treatment applications, the recovery figure is at least 90%. As recovery is increased (to decrease concentrated solute volume), the concentration of solute and suspended solids in the concentrate stream increases.

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