Ammonium solutions, concentration

Sulfates. Indium metal and its oxides dissolve in warm sulfuric acid to give a solution of the trisulfate [13464-82-9], In2(S0 2- It is a white, crystalline, deUquescent soHd, readily soluble in water that forms double salts with alkaLi sulfates and some organic substituted ammonium bases. Concentration of the acidified trisulfate solution produces indium acid sulfate crystal [57344-73-7], In(HS0 2> other reaction conditions give basic sulfates. 

The normal salt, CH COONH, is a white, deUquescent, crystalline soHd, formula wt 77.08, having a specific gravity of 1.073. It is quite soluble in water or ethanol 148 g dissolve in 100 g of water at 4°C. The salt s solubiUty in water increases only slightly as temperature increases up to about 25 °C. The specific gravity of aqueous neutral ammonium acetate ranges from 1.022 to 1.092 as solution concentration increases from 10 to 50 wt % (4). The normal salt melts at 114°C, but decomposes before reaching its boiling point. 

Both batch and continuous processes employ excess sulfur and operate at 85—110°C. Trace amounts of polysulftdes produce a yellow color which iadicates that all the ammonium sulfite has been consumed. Ammonium bisulfite is added to convert the last polysulfide to thiosulfate and the excess ammonia to ammonium sulfite. Concentrations of at least 70% (NH 2S2 3 obtained without evaporation. Excess sulfur is removed by filtration and color is improved with activated carbon treatment or sodium siUcate (66). Upon cooling the aqueous concentrated solution, ammonium thiosulfate crystallines. 

Using aqueous ammonium chloride solution, elution was performed by passing through the column 20 liters of eluent in which the concentration of ammonium chloride was continually increased from 0.05 to 1. OM. The unreacted bleomycinic acid was found in the effluent at the ammonium chloride concentration of about 0.05M and NK631 at the ammonium chloride concentration of about 0.45 M. Both fractions, which showed UV absorption at 292 m/u, were separately collected. 

The reaction occurs in two steps ammonium carbamate is formed first, followed by a decomposition step of the carbamate to urea and water. The first reaction is exothermic, and the equilibrium is favored at lower temperatures and higher pressures. Higher operating pressures are also desirable for the separation absorption step that results in a higher carbamate solution concentration. A higher ammonia ratio than stoichiometric is used to compensate for the ammonia that dissolves in the melt. The reactor temperature ranges between 170-220°C at a pressure of about 200 atmospheres. 

Nitrogen compounds These also arise from both natural and synthetic sources. Thus ammonia is formed in the atmosphere during electrical storms, but increases in the ammonium ion concentration in rainfall over Europe in recent years are attributed to increased use of artiflcial fertilisers. Ammonium compounds in solution may increase the wettability of a metaland the action of ammonia and its compounds in causing season cracking , a type of stress-corrosion cracking of cold-worked brass, is well documented. 

An initial solution was prepared by the hydrofluoride method, i.e. melting of a mixture of ammonium hydrofluoride and tantalite, followed by the digestion of soluble components with water and separation of the solution by filtration. The prepared initial solution contained no free HF or any other acid, and had a pH 3. In order to obtain an optimal acidity level, sulfuric acid was added to the solution. Concentrations of Ta2Os (50-60 g/1) and Nb205 ( 30 g/1) were kept approximately constant during the preparation of the solutions. Extraction was performed using a polypropylene beaker and a magnetic stirrer. 

The interaction described in Equation (148), in which C02 separates from the solution and ammonia hydroxide is formed, reduces the acidity of the solution causing precipitation of tantalum or niobium hydroxide. The hydroxide powder precipitated using ammonium carbonate is usually coarser and has better filtering properties. Changing the ammonium carbonate concentration and temperature of the solution allows some control over the particle size and filtering properties of the precipitated hydroxides. 

Buffer solution, concentrated. Dissolve 27.5 g ammonium acetate and 11.0 g hydrated sodium acetate in 100 mL water add 1.0 mL glacial acetic (ethanoic) acid and mix well. 

During the lifetime of a root, considerable depletion of the available mineral nutrients (MN) in the rhizosphere is to be expected. This, in turn, will affect the equilibrium between available and unavailable forms of MN. For example, dissolution of insoluble calcium or iron phosphates may occur, clay-fixed ammonium or potassium may be released, and nonlabile forms of P associated with clay and sesquioxide surfaces may enter soil solution (10). Any or all of these conversions to available forms will act to buffer the soil solution concentrations and reduce the intensity of the depletion curves around the root. However, because they occur relatively slowly (e.g., over hours, days, or weeks), they cannot be accounted for in the buffer capacity term and have to be included as separate source (dCldl) terms in Eq. (8). Such source terms are likely to be highly soil specific and difficult to measure (11). Many rhizosphere modelers have chosen to ignore them altogether, either by dealing with soils in which they are of limited importance or by growing plants for relatively short periods of time, where their contribution is small. Where such terms have been included, it is common to find first-order kinetic equations being used to describe the rate of interconversion (12). 

The effect of ammonium nitrate concentration on the peak height of a 60ng Atrazine standard solution is shown in Fig. 9.8, the optimum response being at a concentration of approximately 4pg pL-1. 

Ion chromatography is a convenient method for simultaneous determination of alkali, alkaline earth and ammonium ion concentrations in solution. The identity of the analytes is set by the retention times and quantation is carried out by a detector. Conductivity is frequently used, after chemical suppression of the eluate, by which chloride counterions were exchanged by hydroxide. UVV spectrophotometric measurement of hydroxide ions at 200 nm was proposed as an alternative method to suppressed conductivity. Both methods... 

Reactions with organic acids such as formic, acetic, benzoic, oxalic, and salicylic acids produce their corresponding ammonium salts concentrated ammonia solution in excess forms ammonium stearate, CH3 (CH2)i6 COONH4 with stearic acid. 

At water vapor concentrations above the deliquescence point, the equilibrium is that between the reactant gases and aqueous ammonium nitrate. As treated in detail by Mozurkewich, the equilibrium constant, K 4-54, then depends on the solution concentrations or activities ... 

Ammonia is used in the production of several chemicals to make nylon adipic acid, hexa-methylene diamine, and caprolactam. It is used to treat metals in annealing, nitriding, and descaling. Ammonia is an excellent fungicide that is used to treat citric fruit. It is also used to increase the nitrogen content of crops used as feed for livestock. Ammonia dissolves readily in water to produce aqueous ammonia or ammonium hydroxide NH + 2 < > NH4+(a(i) + OH (ahydroxide ions shows that ammonia acts as a base in aqueous solution. Concentrated aqueous solutions contain 35% ammonia. Household ammonia cleaners contain between 5% and 10% ammonia. 

Cobalt and Nickel Ammines. First add a little, and then an excess of a concentrated ammonia solution to solutions of cobalt(II) and nickel(II) salts. What do you observe Boil the ammonium solution of the cobalt salt while shaking the test tube (for what purpose ). Explain the changes in its colour. Write the equations of the reactions. 

Figure 3-4 Hypothetical behavior of a solution containing three proteins, A, B, and C, upon ammonium sulfate fractionation. The concentration of protein remaining in the solution is plotted against ammonium sulfate concentration (usually expressed as % saturation). Addition of ammonium sulfate to concentration c, will precipitate largely protein B, which can he removed by centrifugation. Addition of additional salt to c2 will precipitate largely protein C, while A remains in solution.

The acid and base analogs of ammonia as a solvent is specified by this equilibrium as NH41 and NH inns. All substances which undergo ammonolysis and hence bring about an increase in the ammonium ion concentration yield acitl solutions Thus P S, dissolves in liquid ammonia to give an acid solution as follows. 

Samples, even at moderate concentrations, injected into the HPLC column may precipitate in the mobile phase or at the column frit. In addition, the presence of other compounds (e.g., lipids) in the injection sample may drive the carotenoids out of solution or precipitate themselves in the mobile phase, trapping carotenoids. It is best to dissolve the sample in the mobile phase or a slightly weaker solvent to avoid these problems. Centrifugation or filtration of the samples prior to injection will prevent the introduction of particles that may block the frit, fouling the column and resulting in elevated column pressure. In addition to precipitation, other sources of on-column losses of carotenoids include nonspecific adsorption and oxidation. These can be minimized by incorporating modifiers into the mobile phase (Epler et al., 1993). Triethylamine or diisopropyl ethylamine at 0.1% (v/v) and ammonium acetate at 5 to 50 mM has been successful for this purpose. Since ammonium acetate is poorly soluble in acetonitrile, it should be dissolved in the alcoholic component of the mobile phase prior to mixing with other components. The ammonium acetate concentration in mobile phases composed primarily of acetonitrile must be mixed at lower concentration to avoid precipitation. In some cases, stainless steel frits have been reported to cause oxidative losses of carotenoids (Epler et al., 1992). When available, columns should be obtained with biocompatible frits such as titanium, Hastolloy C, or PEEK. 

The majority of the immunoglobulins in serum will precipitate at ammonium sulphate concentrations equivalent to 50% saturation. This concentration of ammonium sulphate can be achieved either by adding the required weight of ammonium sulphate or by adding an equal volume of a saturated solution of the salt. The former procedure can be quicker in that the prior preparation of a saturated... 

To a solution of 22.7 g of quinone monoguanylhydrazone nitrate in 250 ml water is added dropwise hot aqueous solution of 9.1 g thiosemicarbazide, then is added slowly a solution of 5 ml concentrated nitric acid in 10 ml of water. The mixture is stirred at 60°C for 1 hour. The product is dissolved in 1-1.2 L of water at 100°C. The solution is filtered and added to an aqueous ammonium solution. Blue residue of p-benzoquinone amidinohydrazone thiosemicarbazone is filtered and dried, melting point 188°C (decomp.). 

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