Color in solution

If we assume that the indicator s color in solution changes from that of Inox to that of In ed when the ratio [Inred]/[Inox] changes from 0.1 to 10, then the end point occurs when the solution s electrochemical potential is within the range... 

A number of reaction products have been isolated from the (Tj -C H )2TiCl —N2—reductant system, where n = 1, 2, all of which assume an intense blue color in solution. Spectroscopic absorption occurs at a maximum, of ca 600 nm. The relationship among these products is unclear (185,186), but the labihty of the ring maybe an important complicating factor. When (Tj -C R 2TiCl2 [11136-36-0] R = CH3, is used, two distinct interconvertible... 

Theaflavins. One of the more well-defined groups of flavonoid polymers that forms duriag black tea manufacturiag is that of the theaflavins (14). Exhibiting a bright orange-red color in solution, these are important contributors of brightness, a desirable visual attribute used by professional tasters to describe the appearance of tea infusions. 

The earliest use of gold complexes in medicine primarily involved gold thiolates, which being yellow or even gold-colored in solution, led to their designation as chrysotherapy (chrysos is Greek for gold). 

The product of chemical reactions, namely precipitations (their appearance, color, and crystal shape), colors in solution, gases (their appearance, bubbles, and color), and sublimates... 

Many distibines and dibismuthines have lighter colors in solutions or melts than in the solid state. Crystals of these thermochromic distibines or dibismuthines consist of linear chains of the dimetal compounds with short intermolecular metal-metal contacts. Delocalization of electrons along the chains is possibly responsible for the bathochromic shift between fluid and solid phases. Usually, the /raor-conformation is adopted by the tetraorganodimetal compounds in the solid state. (CF3)4As2 shows the /ra r-conformation also in the gas phase. Photoelectrospectroscopic measurements on Me4Sb2 revealed the presence of gauche- (12%) and trans- (88%) conformed in the gas phase.52... 

According to Hokslev, alkaline chromate of potassa produces a green color in solutions of sugar, easily detected in a few drops., ... 

The 8X12 library was simply irradiated with a hand-held UV lamp (365 nm) to discriminate easily fluorescent and nonfluorescent polymers and to visualize the corresponding emission color in solution. Then, with a spectrofluorimeter able to read 96-well plates for several excitation and emission wavelength combinations, the different excitation wavelengths were evaluated. By this procedure, new polymers showing green (39a,b, excitation at 460 nm, emission detection at 530 nm) or blue (39c-e, excitation at 360 nm, emission detection at 460 nm) emitting fluorescence were rapidly discovered (Fig. 5.13). 

Calculation Determine the color in solution by the following formula ... 

Lakes are insoluble forms of the dyes and are obtained by combining the color with aluminum or calcium hydroxide. The dyes provide color in solution, and the lakes serve as insoluble pigments. 

For acid-base titrations, organic compounds that exhibit different colors in solutions of different acidities used to determine the point at which reaction between two solutes is complete. 

The pH of solutions may be measured experimentally with an electronic pH meter (highly accurate pH meters can measure to 0.001 pH units) or by using acid base indicators, chemicals that change color in solutions of different pH. A crude but common test for pH involves the use of Hydrion paper strips (litmus paper) that undergo changes similar to those found in indicator solutions. For example, red litmus paper turns blue in a basic solution. 

Certain dyes, known as indicators, turn different colors in solutions of different pH. The pH paper pictured in Figure 12 contains a variety of indicators and can develop a rainbow of colors, each of which corresponds to a particular pH value. 

Ascorbic acid will destroy many of the FD C azo colors in solution, so stable colorants must be chosen. 

Acepromazine is a water-soluble agent that appears yellow in color in solution. It is available as a 10 mg/ml solution or as 10 mg or 25 mg tablets... 

A number of inorganic species also absorb. We have noted that many ions of the transition metals are colored in solution and can thus be determined by spectrophotometric measurement. In addition, a number of other species show characteristic absorption peaks, including nitrite, nitrate, and chromate ions, the oxides of nitrogen, the elemental halogens, and ozone. 

The pH of a solution can be determined using a pH meter (Figure 18-1) or by the indicator method. Acid-base indicators are intensely colored complex organic compounds that have different colors in solutions of different pH (Section 19-4). Many are weak acids or weak bases that are useful over rather narrow ranges of pH values. Universal indicators are mixtures of several indicators they show several color changes over a wide range of pH values. 

Indicator An organic compound that exhibits different colors in solutions of different acidities. 

Metallo-dependent acid phosphatases (a.k.a. purple acid phosphatases) contain a binuclear ion center [18, 19] in the active site which confers a characteristic purple color in solution. The color is... 

Transients causing a yellow color in solutions of Cr(CO) 6, Mo(CO) a, and W(CO)a in ether-isopentane appear not to be pentacarbonyls 14a> but ether complexes of these species 136). 

Both research projects require each of her triumvirate making, measuring, and modeling. Murphy has to make—synthesize her nanorods, a multi-step process that will remind non-chemist readers ofundergraduate chemistry labs carefully controlling temperature, pH, solution concentrations, reaction times, etc. The synthesized rods have to be measured— characterized —and here Murphy leans heavily on USC s Electron Microscopy Lab. Now she has rods of known aspect ratios, she knows how various properties—such as color in solution depend on index ratios. But why Here models for how the index ratio of the rods affects the absorption of radiation are necessary. 

Figure 2.32 Absorption spectra of some higher fullerenes. The pure compounds also show very characteristic color In solution. The spectra of and C were obtained after enriching by HPLC the respective substances from a mixed fraction containing both ( JCS 1991).

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