Laboratory solutions

This reaction accounts for the fact that laboratory solutions of KMn04 slowly decompose, producing a brownish solid (Mn02) and gas bubbles (02). 

As a rule laboratory solutions of the indicators contain 0.5-1 g of indicator per litre of solvent. If the substance is soluble in water, e.g. a sodium salt, water is the solvent in most other cases 70-90 per cent ethanol is employed. 

Observations of the ratio of oxidized plutonium to reduced plutonium may provide some insight to the observations of erratic formation and lack of equilibration in laboratory solutions at ORNL versus fairly consistent and predictable behavior in oligo-trophic lakes and marine systems. In coastal water and the relatively shallow Lake Michigan, Pu(V) is about 90 percent of the soluble plutonium, but in the upper waters of the open ocean, where it does not interact with the seafloor due to the depths,... 

As we have already seen, base concentrations around 10 M are common. This concentration is a bit lower but still in the range that we would expect for laboratory solutions. 

In the laboratory, solutions of analytes that fluoresce are tested by measuring the intensity of the light emitted. The instrument for measuring fluorescence intensity is called a fluorometer. Inexpensive instruments used for routine work utilize absorption filters similar to what was described previously for absorption spectrophotometers (see Figure 8.2 and accompanying discussion) and are called filter fluorometers. Two such filters are needed—one to isolate the wavelength from the source to be absorbed, the wavelength... 

Eh-pH diagrams are sometimes used to predict or describe the major dissolved species and precipitates that should exist at equilibrium in aqueous solutions, including groundwaters, surface waters, laboratory solutions, and porewaters from soils, sediments, or rocks. However, as previously described, many natural aqueous systems are not at equilibrium and they often contain metastable species that are not predicted by Eh-pH diagrams. Metastable species refer to compounds, other substances, or ions that are present under redox, pH, pressure, temperature, or other conditions where chemical equilibrium indicates that they should be unstable and absent. Many metastable species (such as As(III) in oxygenated seawater) result from biological activity. 

Walker, Schreiber and Rimstidt (2006) list the oxidation rate of arsenopyrite in water as io 1014 0 03 mol m-2 s-1 at 25 °C, pH 6.3-6.7, and dissolved 02 concentrations of 0.3-17 mgL-1. Unexpectedly, the dissolved 02 concentrations had essentially no effect on the oxidation rate. However, in laboratory solutions simulating acid mine drainage (pH = 1.8), the oxidation rate of arsenopyrite was found to increase with increasing temperature (15-45 °C) and concentrations of chloride or Fe(III) sulfate (Fe2(S04)3) (Yu, Zhu and Gao, 2004). The oxidation of arsenopyrite primarily released As(III). The oxidation of As(III) to As(V) was slow, but also increased with increasing temperature and chloride or Fe(III) sulfate concentrations (Yu, Zhu and Gao, 2004). 

Carbon (granular activated with Laboratory solutions 25 1 4.70 As(V)... 

Drinking water treatment residuals (iron rich) Laboratory solutions 23 2 6.0 0.3 As(lll)... 

FIBAN-As (Ion-exchange polymeric fibers impregnated with iron [oxy][hydr] oxides) Laboratory solutions 20 2 9 As(lll)... 

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