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This is evidenced by the 2007 pet food incident and the 2008 Chinese milk powder scandal, when melamine, a nitrogen-rich chemical, was added to raw materials to fake high protein contents. Also, different correction factors are needed for different proteins to account for different amino acid sequences.
Sulfate-reducing microorganisms are responsible for the sulfurous odors of salt marshes and mud flats. Much of the hydrogen sulfide will react with metal ions in the water to produce metal sulfides. These metal sulfides, such as ferrous sulfide (FeS), are insoluble and often black or brown, leading to the dark color of sludge. [2]
Sodium sulfate is a typical electrostatically bonded ionic sulfate. The existence of free sulfate ions in solution is indicated by the easy formation of insoluble sulfates when these solutions are treated with Ba 2+ or Pb 2+ salts: Na 2 SO 4 + BaCl 2 → 2 NaCl + BaSO 4. Sodium sulfate is unreactive toward most oxidizing or reducing agents.
This is a common laboratory test to determine if sulfate anions are present. The sulfate ion can act as a ligand attaching either by one oxygen (monodentate) or by two oxygens as either a chelate or a bridge. [7] An example is the complex Co 2 (SO 4)] + Br − [7] or the neutral metal complex PtSO 4 (PPh 3) 2] where the sulfate ion is acting as ...
Reactions of oxidation of sulfide to sulfate and elemental sulfur (incorrectly balanced). The electrons (e −) liberated from these oxidation reactions, which release chemical energy, are then used to fix carbon into organic molecules. The elements that become oxidized are shown in pink, those that become reduced in blue, and the electrons in ...
Gravimetric analysis describes a set of methods used in analytical chemistry for the quantitative determination of an analyte (the ion being analyzed) based on its mass. The principle of this type of analysis is that once an ion's mass has been determined as a unique compound, that known measurement can then be used to determine the same analyte's mass in a mixture, as long as the relative ...
A simple nitrite test can be performed by adding 4 M sulfuric acid to the sample until acidic, and then adding 0.1 M iron(II) sulfate to the solution. A positive test for nitrite is indicated by a dark brown solution, arising from the iron-nitric oxide complex ion.
Benedict's reagent (often called Benedict's qualitative solution or Benedict's solution) is a chemical reagent and complex mixture of sodium carbonate, sodium citrate, and copper(II) sulfate pentahydrate. [1] It is often used in place of Fehling's solution to detect the presence of reducing sugars and other reducing substances. [2]